1 /* ------------------------------------------------------------------ */ 2 /* Decimal Number arithmetic module */ 3 /* ------------------------------------------------------------------ */ 4 /* Copyright (c) IBM Corporation, 2000-2010. All rights reserved. */ 5 /* */ 6 /* This software is made available under the terms of the */ 7 /* ICU License -- ICU 1.8.1 and later. */ 8 /* */ 9 /* The description and User's Guide ("The decNumber C Library") for */ 10 /* this software is called decNumber.pdf. This document is */ 11 /* available, together with arithmetic and format specifications, */ 12 /* testcases, and Web links, on the General Decimal Arithmetic page. */ 13 /* */ 14 /* Please send comments, suggestions, and corrections to the author: */ 15 /* mfc (at) uk.ibm.com */ 16 /* Mike Cowlishaw, IBM Fellow */ 17 /* IBM UK, PO Box 31, Birmingham Road, Warwick CV34 5JL, UK */ 18 /* ------------------------------------------------------------------ */ 19 20 /* Modified version, for use from within ICU. 21 * Renamed public functions, to avoid an unwanted export of the 22 * standard names from the ICU library. 23 * 24 * Use ICU's uprv_malloc() and uprv_free() 25 * 26 * Revert comment syntax to plain C 27 * 28 * Remove a few compiler warnings. 29 */ 30 31 /* This module comprises the routines for arbitrary-precision General */ 32 /* Decimal Arithmetic as defined in the specification which may be */ 33 /* found on the General Decimal Arithmetic pages. It implements both */ 34 /* the full ('extended') arithmetic and the simpler ('subset') */ 35 /* arithmetic. */ 36 /* */ 37 /* Usage notes: */ 38 /* */ 39 /* 1. This code is ANSI C89 except: */ 40 /* */ 41 /* a) C99 line comments (double forward slash) are used. (Most C */ 42 /* compilers accept these. If yours does not, a simple script */ 43 /* can be used to convert them to ANSI C comments.) */ 44 /* */ 45 /* b) Types from C99 stdint.h are used. If you do not have this */ 46 /* header file, see the User's Guide section of the decNumber */ 47 /* documentation; this lists the necessary definitions. */ 48 /* */ 49 /* c) If DECDPUN>4 or DECUSE64=1, the C99 64-bit int64_t and */ 50 /* uint64_t types may be used. To avoid these, set DECUSE64=0 */ 51 /* and DECDPUN<=4 (see documentation). */ 52 /* */ 53 /* The code also conforms to C99 restrictions; in particular, */ 54 /* strict aliasing rules are observed. */ 55 /* */ 56 /* 2. The decNumber format which this library uses is optimized for */ 57 /* efficient processing of relatively short numbers; in particular */ 58 /* it allows the use of fixed sized structures and minimizes copy */ 59 /* and move operations. It does, however, support arbitrary */ 60 /* precision (up to 999,999,999 digits) and arbitrary exponent */ 61 /* range (Emax in the range 0 through 999,999,999 and Emin in the */ 62 /* range -999,999,999 through 0). Mathematical functions (for */ 63 /* example decNumberExp) as identified below are restricted more */ 64 /* tightly: digits, emax, and -emin in the context must be <= */ 65 /* DEC_MAX_MATH (999999), and their operand(s) must be within */ 66 /* these bounds. */ 67 /* */ 68 /* 3. Logical functions are further restricted; their operands must */ 69 /* be finite, positive, have an exponent of zero, and all digits */ 70 /* must be either 0 or 1. The result will only contain digits */ 71 /* which are 0 or 1 (and will have exponent=0 and a sign of 0). */ 72 /* */ 73 /* 4. Operands to operator functions are never modified unless they */ 74 /* are also specified to be the result number (which is always */ 75 /* permitted). Other than that case, operands must not overlap. */ 76 /* */ 77 /* 5. Error handling: the type of the error is ORed into the status */ 78 /* flags in the current context (decContext structure). The */ 79 /* SIGFPE signal is then raised if the corresponding trap-enabler */ 80 /* flag in the decContext is set (is 1). */ 81 /* */ 82 /* It is the responsibility of the caller to clear the status */ 83 /* flags as required. */ 84 /* */ 85 /* The result of any routine which returns a number will always */ 86 /* be a valid number (which may be a special value, such as an */ 87 /* Infinity or NaN). */ 88 /* */ 89 /* 6. The decNumber format is not an exchangeable concrete */ 90 /* representation as it comprises fields which may be machine- */ 91 /* dependent (packed or unpacked, or special length, for example). */ 92 /* Canonical conversions to and from strings are provided; other */ 93 /* conversions are available in separate modules. */ 94 /* */ 95 /* 7. Normally, input operands are assumed to be valid. Set DECCHECK */ 96 /* to 1 for extended operand checking (including NULL operands). */ 97 /* Results are undefined if a badly-formed structure (or a NULL */ 98 /* pointer to a structure) is provided, though with DECCHECK */ 99 /* enabled the operator routines are protected against exceptions. */ 100 /* (Except if the result pointer is NULL, which is unrecoverable.) */ 101 /* */ 102 /* However, the routines will never cause exceptions if they are */ 103 /* given well-formed operands, even if the value of the operands */ 104 /* is inappropriate for the operation and DECCHECK is not set. */ 105 /* (Except for SIGFPE, as and where documented.) */ 106 /* */ 107 /* 8. Subset arithmetic is available only if DECSUBSET is set to 1. */ 108 /* ------------------------------------------------------------------ */ 109 /* Implementation notes for maintenance of this module: */ 110 /* */ 111 /* 1. Storage leak protection: Routines which use malloc are not */ 112 /* permitted to use return for fastpath or error exits (i.e., */ 113 /* they follow strict structured programming conventions). */ 114 /* Instead they have a do{}while(0); construct surrounding the */ 115 /* code which is protected -- break may be used to exit this. */ 116 /* Other routines can safely use the return statement inline. */ 117 /* */ 118 /* Storage leak accounting can be enabled using DECALLOC. */ 119 /* */ 120 /* 2. All loops use the for(;;) construct. Any do construct does */ 121 /* not loop; it is for allocation protection as just described. */ 122 /* */ 123 /* 3. Setting status in the context must always be the very last */ 124 /* action in a routine, as non-0 status may raise a trap and hence */ 125 /* the call to set status may not return (if the handler uses long */ 126 /* jump). Therefore all cleanup must be done first. In general, */ 127 /* to achieve this status is accumulated and is only applied just */ 128 /* before return by calling decContextSetStatus (via decStatus). */ 129 /* */ 130 /* Routines which allocate storage cannot, in general, use the */ 131 /* 'top level' routines which could cause a non-returning */ 132 /* transfer of control. The decXxxxOp routines are safe (do not */ 133 /* call decStatus even if traps are set in the context) and should */ 134 /* be used instead (they are also a little faster). */ 135 /* */ 136 /* 4. Exponent checking is minimized by allowing the exponent to */ 137 /* grow outside its limits during calculations, provided that */ 138 /* the decFinalize function is called later. Multiplication and */ 139 /* division, and intermediate calculations in exponentiation, */ 140 /* require more careful checks because of the risk of 31-bit */ 141 /* overflow (the most negative valid exponent is -1999999997, for */ 142 /* a 999999999-digit number with adjusted exponent of -999999999). */ 143 /* */ 144 /* 5. Rounding is deferred until finalization of results, with any */ 145 /* 'off to the right' data being represented as a single digit */ 146 /* residue (in the range -1 through 9). This avoids any double- */ 147 /* rounding when more than one shortening takes place (for */ 148 /* example, when a result is subnormal). */ 149 /* */ 150 /* 6. The digits count is allowed to rise to a multiple of DECDPUN */ 151 /* during many operations, so whole Units are handled and exact */ 152 /* accounting of digits is not needed. The correct digits value */ 153 /* is found by decGetDigits, which accounts for leading zeros. */ 154 /* This must be called before any rounding if the number of digits */ 155 /* is not known exactly. */ 156 /* */ 157 /* 7. The multiply-by-reciprocal 'trick' is used for partitioning */ 158 /* numbers up to four digits, using appropriate constants. This */ 159 /* is not useful for longer numbers because overflow of 32 bits */ 160 /* would lead to 4 multiplies, which is almost as expensive as */ 161 /* a divide (unless a floating-point or 64-bit multiply is */ 162 /* assumed to be available). */ 163 /* */ 164 /* 8. Unusual abbreviations that may be used in the commentary: */ 165 /* lhs -- left hand side (operand, of an operation) */ 166 /* lsd -- least significant digit (of coefficient) */ 167 /* lsu -- least significant Unit (of coefficient) */ 168 /* msd -- most significant digit (of coefficient) */ 169 /* msi -- most significant item (in an array) */ 170 /* msu -- most significant Unit (of coefficient) */ 171 /* rhs -- right hand side (operand, of an operation) */ 172 /* +ve -- positive */ 173 /* -ve -- negative */ 174 /* ** -- raise to the power */ 175 /* ------------------------------------------------------------------ */ 176 177 #include <stdlib.h> /* for malloc, free, etc. */ 178 /* #include <stdio.h> */ /* for printf [if needed] */ 179 #include <string.h> /* for strcpy */ 180 #include <ctype.h> /* for lower */ 181 #include "cmemory.h" /* for uprv_malloc, etc., in ICU */ 182 #include "decNumber.h" /* base number library */ 183 #include "decNumberLocal.h" /* decNumber local types, etc. */ 184 185 /* Constants */ 186 /* Public lookup table used by the D2U macro */ 187 const uByte d2utable[DECMAXD2U+1]=D2UTABLE; 188 189 #define DECVERB 1 /* set to 1 for verbose DECCHECK */ 190 #define powers DECPOWERS /* old internal name */ 191 192 /* Local constants */ 193 #define DIVIDE 0x80 /* Divide operators */ 194 #define REMAINDER 0x40 /* .. */ 195 #define DIVIDEINT 0x20 /* .. */ 196 #define REMNEAR 0x10 /* .. */ 197 #define COMPARE 0x01 /* Compare operators */ 198 #define COMPMAX 0x02 /* .. */ 199 #define COMPMIN 0x03 /* .. */ 200 #define COMPTOTAL 0x04 /* .. */ 201 #define COMPNAN 0x05 /* .. [NaN processing] */ 202 #define COMPSIG 0x06 /* .. [signaling COMPARE] */ 203 #define COMPMAXMAG 0x07 /* .. */ 204 #define COMPMINMAG 0x08 /* .. */ 205 206 #define DEC_sNaN 0x40000000 /* local status: sNaN signal */ 207 #define BADINT (Int)0x80000000 /* most-negative Int; error indicator */ 208 /* Next two indicate an integer >= 10**6, and its parity (bottom bit) */ 209 #define BIGEVEN (Int)0x80000002 210 #define BIGODD (Int)0x80000003 211 212 static Unit uarrone[1]={1}; /* Unit array of 1, used for incrementing */ 213 214 /* Granularity-dependent code */ 215 #if DECDPUN<=4 216 #define eInt Int /* extended integer */ 217 #define ueInt uInt /* unsigned extended integer */ 218 /* Constant multipliers for divide-by-power-of five using reciprocal */ 219 /* multiply, after removing powers of 2 by shifting, and final shift */ 220 /* of 17 [we only need up to **4] */ 221 static const uInt multies[]={131073, 26215, 5243, 1049, 210}; 222 /* QUOT10 -- macro to return the quotient of unit u divided by 10**n */ 223 #define QUOT10(u, n) ((((uInt)(u)>>(n))*multies[n])>>17) 224 #else 225 /* For DECDPUN>4 non-ANSI-89 64-bit types are needed. */ 226 #if !DECUSE64 227 #error decNumber.c: DECUSE64 must be 1 when DECDPUN>4 228 #endif 229 #define eInt Long /* extended integer */ 230 #define ueInt uLong /* unsigned extended integer */ 231 #endif 232 233 /* Local routines */ 234 static decNumber * decAddOp(decNumber *, const decNumber *, const decNumber *, 235 decContext *, uByte, uInt *); 236 static Flag decBiStr(const char *, const char *, const char *); 237 static uInt decCheckMath(const decNumber *, decContext *, uInt *); 238 static void decApplyRound(decNumber *, decContext *, Int, uInt *); 239 static Int decCompare(const decNumber *lhs, const decNumber *rhs, Flag); 240 static decNumber * decCompareOp(decNumber *, const decNumber *, 241 const decNumber *, decContext *, 242 Flag, uInt *); 243 static void decCopyFit(decNumber *, const decNumber *, decContext *, 244 Int *, uInt *); 245 static decNumber * decDecap(decNumber *, Int); 246 static decNumber * decDivideOp(decNumber *, const decNumber *, 247 const decNumber *, decContext *, Flag, uInt *); 248 static decNumber * decExpOp(decNumber *, const decNumber *, 249 decContext *, uInt *); 250 static void decFinalize(decNumber *, decContext *, Int *, uInt *); 251 static Int decGetDigits(Unit *, Int); 252 static Int decGetInt(const decNumber *); 253 static decNumber * decLnOp(decNumber *, const decNumber *, 254 decContext *, uInt *); 255 static decNumber * decMultiplyOp(decNumber *, const decNumber *, 256 const decNumber *, decContext *, 257 uInt *); 258 static decNumber * decNaNs(decNumber *, const decNumber *, 259 const decNumber *, decContext *, uInt *); 260 static decNumber * decQuantizeOp(decNumber *, const decNumber *, 261 const decNumber *, decContext *, Flag, 262 uInt *); 263 static void decReverse(Unit *, Unit *); 264 static void decSetCoeff(decNumber *, decContext *, const Unit *, 265 Int, Int *, uInt *); 266 static void decSetMaxValue(decNumber *, decContext *); 267 static void decSetOverflow(decNumber *, decContext *, uInt *); 268 static void decSetSubnormal(decNumber *, decContext *, Int *, uInt *); 269 static Int decShiftToLeast(Unit *, Int, Int); 270 static Int decShiftToMost(Unit *, Int, Int); 271 static void decStatus(decNumber *, uInt, decContext *); 272 static void decToString(const decNumber *, char[], Flag); 273 static decNumber * decTrim(decNumber *, decContext *, Flag, Flag, Int *); 274 static Int decUnitAddSub(const Unit *, Int, const Unit *, Int, Int, 275 Unit *, Int); 276 static Int decUnitCompare(const Unit *, Int, const Unit *, Int, Int); 277 278 #if !DECSUBSET 279 /* decFinish == decFinalize when no subset arithmetic needed */ 280 #define decFinish(a,b,c,d) decFinalize(a,b,c,d) 281 #else 282 static void decFinish(decNumber *, decContext *, Int *, uInt *); 283 static decNumber * decRoundOperand(const decNumber *, decContext *, uInt *); 284 #endif 285 286 /* Local macros */ 287 /* masked special-values bits */ 288 #define SPECIALARG (rhs->bits & DECSPECIAL) 289 #define SPECIALARGS ((lhs->bits | rhs->bits) & DECSPECIAL) 290 291 /* For use in ICU */ 292 #define malloc(a) uprv_malloc(a) 293 #define free(a) uprv_free(a) 294 295 /* Diagnostic macros, etc. */ 296 #if DECALLOC 297 /* Handle malloc/free accounting. If enabled, our accountable routines */ 298 /* are used; otherwise the code just goes straight to the system malloc */ 299 /* and free routines. */ 300 #define malloc(a) decMalloc(a) 301 #define free(a) decFree(a) 302 #define DECFENCE 0x5a /* corruption detector */ 303 /* 'Our' malloc and free: */ 304 static void *decMalloc(size_t); 305 static void decFree(void *); 306 uInt decAllocBytes=0; /* count of bytes allocated */ 307 /* Note that DECALLOC code only checks for storage buffer overflow. */ 308 /* To check for memory leaks, the decAllocBytes variable must be */ 309 /* checked to be 0 at appropriate times (e.g., after the test */ 310 /* harness completes a set of tests). This checking may be unreliable */ 311 /* if the testing is done in a multi-thread environment. */ 312 #endif 313 314 #if DECCHECK 315 /* Optional checking routines. Enabling these means that decNumber */ 316 /* and decContext operands to operator routines are checked for */ 317 /* correctness. This roughly doubles the execution time of the */ 318 /* fastest routines (and adds 600+ bytes), so should not normally be */ 319 /* used in 'production'. */ 320 /* decCheckInexact is used to check that inexact results have a full */ 321 /* complement of digits (where appropriate -- this is not the case */ 322 /* for Quantize, for example) */ 323 #define DECUNRESU ((decNumber *)(void *)0xffffffff) 324 #define DECUNUSED ((const decNumber *)(void *)0xffffffff) 325 #define DECUNCONT ((decContext *)(void *)(0xffffffff)) 326 static Flag decCheckOperands(decNumber *, const decNumber *, 327 const decNumber *, decContext *); 328 static Flag decCheckNumber(const decNumber *); 329 static void decCheckInexact(const decNumber *, decContext *); 330 #endif 331 332 #if DECTRACE || DECCHECK 333 /* Optional trace/debugging routines (may or may not be used) */ 334 void decNumberShow(const decNumber *); /* displays the components of a number */ 335 static void decDumpAr(char, const Unit *, Int); 336 #endif 337 338 /* ================================================================== */ 339 /* Conversions */ 340 /* ================================================================== */ 341 342 /* ------------------------------------------------------------------ */ 343 /* from-int32 -- conversion from Int or uInt */ 344 /* */ 345 /* dn is the decNumber to receive the integer */ 346 /* in or uin is the integer to be converted */ 347 /* returns dn */ 348 /* */ 349 /* No error is possible. */ 350 /* ------------------------------------------------------------------ */ 351 U_CAPI decNumber * U_EXPORT2 uprv_decNumberFromInt32(decNumber *dn, Int in) { 352 uInt unsig; 353 if (in>=0) unsig=in; 354 else { /* negative (possibly BADINT) */ 355 if (in==BADINT) unsig=(uInt)1073741824*2; /* special case */ 356 else unsig=-in; /* invert */ 357 } 358 /* in is now positive */ 359 uprv_decNumberFromUInt32(dn, unsig); 360 if (in<0) dn->bits=DECNEG; /* sign needed */ 361 return dn; 362 } /* decNumberFromInt32 */ 363 364 U_CAPI decNumber * U_EXPORT2 uprv_decNumberFromUInt32(decNumber *dn, uInt uin) { 365 Unit *up; /* work pointer */ 366 uprv_decNumberZero(dn); /* clean */ 367 if (uin==0) return dn; /* [or decGetDigits bad call] */ 368 for (up=dn->lsu; uin>0; up++) { 369 *up=(Unit)(uin%(DECDPUNMAX+1)); 370 uin=uin/(DECDPUNMAX+1); 371 } 372 dn->digits=decGetDigits(dn->lsu, up-dn->lsu); 373 return dn; 374 } /* decNumberFromUInt32 */ 375 376 /* ------------------------------------------------------------------ */ 377 /* to-int32 -- conversion to Int or uInt */ 378 /* */ 379 /* dn is the decNumber to convert */ 380 /* set is the context for reporting errors */ 381 /* returns the converted decNumber, or 0 if Invalid is set */ 382 /* */ 383 /* Invalid is set if the decNumber does not have exponent==0 or if */ 384 /* it is a NaN, Infinite, or out-of-range. */ 385 /* ------------------------------------------------------------------ */ 386 U_CAPI Int U_EXPORT2 uprv_decNumberToInt32(const decNumber *dn, decContext *set) { 387 #if DECCHECK 388 if (decCheckOperands(DECUNRESU, DECUNUSED, dn, set)) return 0; 389 #endif 390 391 /* special or too many digits, or bad exponent */ 392 if (dn->bits&DECSPECIAL || dn->digits>10 || dn->exponent!=0) ; /* bad */ 393 else { /* is a finite integer with 10 or fewer digits */ 394 Int d; /* work */ 395 const Unit *up; /* .. */ 396 uInt hi=0, lo; /* .. */ 397 up=dn->lsu; /* -> lsu */ 398 lo=*up; /* get 1 to 9 digits */ 399 #if DECDPUN>1 /* split to higher */ 400 hi=lo/10; 401 lo=lo%10; 402 #endif 403 up++; 404 /* collect remaining Units, if any, into hi */ 405 for (d=DECDPUN; d<dn->digits; up++, d+=DECDPUN) hi+=*up*powers[d-1]; 406 /* now low has the lsd, hi the remainder */ 407 if (hi>214748364 || (hi==214748364 && lo>7)) { /* out of range? */ 408 /* most-negative is a reprieve */ 409 if (dn->bits&DECNEG && hi==214748364 && lo==8) return 0x80000000; 410 /* bad -- drop through */ 411 } 412 else { /* in-range always */ 413 Int i=X10(hi)+lo; 414 if (dn->bits&DECNEG) return -i; 415 return i; 416 } 417 } /* integer */ 418 uprv_decContextSetStatus(set, DEC_Invalid_operation); /* [may not return] */ 419 return 0; 420 } /* decNumberToInt32 */ 421 422 U_CAPI uInt U_EXPORT2 uprv_decNumberToUInt32(const decNumber *dn, decContext *set) { 423 #if DECCHECK 424 if (decCheckOperands(DECUNRESU, DECUNUSED, dn, set)) return 0; 425 #endif 426 /* special or too many digits, or bad exponent, or negative (<0) */ 427 if (dn->bits&DECSPECIAL || dn->digits>10 || dn->exponent!=0 428 || (dn->bits&DECNEG && !ISZERO(dn))); /* bad */ 429 else { /* is a finite integer with 10 or fewer digits */ 430 Int d; /* work */ 431 const Unit *up; /* .. */ 432 uInt hi=0, lo; /* .. */ 433 up=dn->lsu; /* -> lsu */ 434 lo=*up; /* get 1 to 9 digits */ 435 #if DECDPUN>1 /* split to higher */ 436 hi=lo/10; 437 lo=lo%10; 438 #endif 439 up++; 440 /* collect remaining Units, if any, into hi */ 441 for (d=DECDPUN; d<dn->digits; up++, d+=DECDPUN) hi+=*up*powers[d-1]; 442 443 /* now low has the lsd, hi the remainder */ 444 if (hi>429496729 || (hi==429496729 && lo>5)) ; /* no reprieve possible */ 445 else return X10(hi)+lo; 446 } /* integer */ 447 uprv_decContextSetStatus(set, DEC_Invalid_operation); /* [may not return] */ 448 return 0; 449 } /* decNumberToUInt32 */ 450 451 /* ------------------------------------------------------------------ */ 452 /* to-scientific-string -- conversion to numeric string */ 453 /* to-engineering-string -- conversion to numeric string */ 454 /* */ 455 /* decNumberToString(dn, string); */ 456 /* decNumberToEngString(dn, string); */ 457 /* */ 458 /* dn is the decNumber to convert */ 459 /* string is the string where the result will be laid out */ 460 /* */ 461 /* string must be at least dn->digits+14 characters long */ 462 /* */ 463 /* No error is possible, and no status can be set. */ 464 /* ------------------------------------------------------------------ */ 465 U_CAPI char * U_EXPORT2 uprv_decNumberToString(const decNumber *dn, char *string){ 466 decToString(dn, string, 0); 467 return string; 468 } /* DecNumberToString */ 469 470 U_CAPI char * U_EXPORT2 uprv_decNumberToEngString(const decNumber *dn, char *string){ 471 decToString(dn, string, 1); 472 return string; 473 } /* DecNumberToEngString */ 474 475 /* ------------------------------------------------------------------ */ 476 /* to-number -- conversion from numeric string */ 477 /* */ 478 /* decNumberFromString -- convert string to decNumber */ 479 /* dn -- the number structure to fill */ 480 /* chars[] -- the string to convert ('\0' terminated) */ 481 /* set -- the context used for processing any error, */ 482 /* determining the maximum precision available */ 483 /* (set.digits), determining the maximum and minimum */ 484 /* exponent (set.emax and set.emin), determining if */ 485 /* extended values are allowed, and checking the */ 486 /* rounding mode if overflow occurs or rounding is */ 487 /* needed. */ 488 /* */ 489 /* The length of the coefficient and the size of the exponent are */ 490 /* checked by this routine, so the correct error (Underflow or */ 491 /* Overflow) can be reported or rounding applied, as necessary. */ 492 /* */ 493 /* If bad syntax is detected, the result will be a quiet NaN. */ 494 /* ------------------------------------------------------------------ */ 495 U_CAPI decNumber * U_EXPORT2 uprv_decNumberFromString(decNumber *dn, const char chars[], 496 decContext *set) { 497 Int exponent=0; /* working exponent [assume 0] */ 498 uByte bits=0; /* working flags [assume +ve] */ 499 Unit *res; /* where result will be built */ 500 Unit resbuff[SD2U(DECBUFFER+9)];/* local buffer in case need temporary */ 501 /* [+9 allows for ln() constants] */ 502 Unit *allocres=NULL; /* -> allocated result, iff allocated */ 503 Int d=0; /* count of digits found in decimal part */ 504 const char *dotchar=NULL; /* where dot was found */ 505 const char *cfirst=chars; /* -> first character of decimal part */ 506 const char *last=NULL; /* -> last digit of decimal part */ 507 const char *c; /* work */ 508 Unit *up; /* .. */ 509 #if DECDPUN>1 510 Int cut, out; /* .. */ 511 #endif 512 Int residue; /* rounding residue */ 513 uInt status=0; /* error code */ 514 515 #if DECCHECK 516 if (decCheckOperands(DECUNRESU, DECUNUSED, DECUNUSED, set)) 517 return uprv_decNumberZero(dn); 518 #endif 519 520 do { /* status & malloc protection */ 521 for (c=chars;; c++) { /* -> input character */ 522 if (*c>='0' && *c<='9') { /* test for Arabic digit */ 523 last=c; 524 d++; /* count of real digits */ 525 continue; /* still in decimal part */ 526 } 527 if (*c=='.' && dotchar==NULL) { /* first '.' */ 528 dotchar=c; /* record offset into decimal part */ 529 if (c==cfirst) cfirst++; /* first digit must follow */ 530 continue;} 531 if (c==chars) { /* first in string... */ 532 if (*c=='-') { /* valid - sign */ 533 cfirst++; 534 bits=DECNEG; 535 continue;} 536 if (*c=='+') { /* valid + sign */ 537 cfirst++; 538 continue;} 539 } 540 /* *c is not a digit, or a valid +, -, or '.' */ 541 break; 542 } /* c */ 543 544 if (last==NULL) { /* no digits yet */ 545 status=DEC_Conversion_syntax;/* assume the worst */ 546 if (*c=='\0') break; /* and no more to come... */ 547 #if DECSUBSET 548 /* if subset then infinities and NaNs are not allowed */ 549 if (!set->extended) break; /* hopeless */ 550 #endif 551 /* Infinities and NaNs are possible, here */ 552 if (dotchar!=NULL) break; /* .. unless had a dot */ 553 uprv_decNumberZero(dn); /* be optimistic */ 554 if (decBiStr(c, "infinity", "INFINITY") 555 || decBiStr(c, "inf", "INF")) { 556 dn->bits=bits | DECINF; 557 status=0; /* is OK */ 558 break; /* all done */ 559 } 560 /* a NaN expected */ 561 /* 2003.09.10 NaNs are now permitted to have a sign */ 562 dn->bits=bits | DECNAN; /* assume simple NaN */ 563 if (*c=='s' || *c=='S') { /* looks like an sNaN */ 564 c++; 565 dn->bits=bits | DECSNAN; 566 } 567 if (*c!='n' && *c!='N') break; /* check caseless "NaN" */ 568 c++; 569 if (*c!='a' && *c!='A') break; /* .. */ 570 c++; 571 if (*c!='n' && *c!='N') break; /* .. */ 572 c++; 573 /* now either nothing, or nnnn payload, expected */ 574 /* -> start of integer and skip leading 0s [including plain 0] */ 575 for (cfirst=c; *cfirst=='0';) cfirst++; 576 if (*cfirst=='\0') { /* "NaN" or "sNaN", maybe with all 0s */ 577 status=0; /* it's good */ 578 break; /* .. */ 579 } 580 /* something other than 0s; setup last and d as usual [no dots] */ 581 for (c=cfirst;; c++, d++) { 582 if (*c<'0' || *c>'9') break; /* test for Arabic digit */ 583 last=c; 584 } 585 if (*c!='\0') break; /* not all digits */ 586 if (d>set->digits-1) { 587 /* [NB: payload in a decNumber can be full length unless */ 588 /* clamped, in which case can only be digits-1] */ 589 if (set->clamp) break; 590 if (d>set->digits) break; 591 } /* too many digits? */ 592 /* good; drop through to convert the integer to coefficient */ 593 status=0; /* syntax is OK */ 594 bits=dn->bits; /* for copy-back */ 595 } /* last==NULL */ 596 597 else if (*c!='\0') { /* more to process... */ 598 /* had some digits; exponent is only valid sequence now */ 599 Flag nege; /* 1=negative exponent */ 600 const char *firstexp; /* -> first significant exponent digit */ 601 status=DEC_Conversion_syntax;/* assume the worst */ 602 if (*c!='e' && *c!='E') break; 603 /* Found 'e' or 'E' -- now process explicit exponent */ 604 /* 1998.07.11: sign no longer required */ 605 nege=0; 606 c++; /* to (possible) sign */ 607 if (*c=='-') {nege=1; c++;} 608 else if (*c=='+') c++; 609 if (*c=='\0') break; 610 611 for (; *c=='0' && *(c+1)!='\0';) c++; /* strip insignificant zeros */ 612 firstexp=c; /* save exponent digit place */ 613 for (; ;c++) { 614 if (*c<'0' || *c>'9') break; /* not a digit */ 615 exponent=X10(exponent)+(Int)*c-(Int)'0'; 616 } /* c */ 617 /* if not now on a '\0', *c must not be a digit */ 618 if (*c!='\0') break; 619 620 /* (this next test must be after the syntax checks) */ 621 /* if it was too long the exponent may have wrapped, so check */ 622 /* carefully and set it to a certain overflow if wrap possible */ 623 if (c>=firstexp+9+1) { 624 if (c>firstexp+9+1 || *firstexp>'1') exponent=DECNUMMAXE*2; 625 /* [up to 1999999999 is OK, for example 1E-1000000998] */ 626 } 627 if (nege) exponent=-exponent; /* was negative */ 628 status=0; /* is OK */ 629 } /* stuff after digits */ 630 631 /* Here when whole string has been inspected; syntax is good */ 632 /* cfirst->first digit (never dot), last->last digit (ditto) */ 633 634 /* strip leading zeros/dot [leave final 0 if all 0's] */ 635 if (*cfirst=='0') { /* [cfirst has stepped over .] */ 636 for (c=cfirst; c<last; c++, cfirst++) { 637 if (*c=='.') continue; /* ignore dots */ 638 if (*c!='0') break; /* non-zero found */ 639 d--; /* 0 stripped */ 640 } /* c */ 641 #if DECSUBSET 642 /* make a rapid exit for easy zeros if !extended */ 643 if (*cfirst=='0' && !set->extended) { 644 uprv_decNumberZero(dn); /* clean result */ 645 break; /* [could be return] */ 646 } 647 #endif 648 } /* at least one leading 0 */ 649 650 /* Handle decimal point... */ 651 if (dotchar!=NULL && dotchar<last) /* non-trailing '.' found? */ 652 exponent-=(last-dotchar); /* adjust exponent */ 653 /* [we can now ignore the .] */ 654 655 /* OK, the digits string is good. Assemble in the decNumber, or in */ 656 /* a temporary units array if rounding is needed */ 657 if (d<=set->digits) res=dn->lsu; /* fits into supplied decNumber */ 658 else { /* rounding needed */ 659 Int needbytes=D2U(d)*sizeof(Unit);/* bytes needed */ 660 res=resbuff; /* assume use local buffer */ 661 if (needbytes>(Int)sizeof(resbuff)) { /* too big for local */ 662 allocres=(Unit *)malloc(needbytes); 663 if (allocres==NULL) {status|=DEC_Insufficient_storage; break;} 664 res=allocres; 665 } 666 } 667 /* res now -> number lsu, buffer, or allocated storage for Unit array */ 668 669 /* Place the coefficient into the selected Unit array */ 670 /* [this is often 70% of the cost of this function when DECDPUN>1] */ 671 #if DECDPUN>1 672 out=0; /* accumulator */ 673 up=res+D2U(d)-1; /* -> msu */ 674 cut=d-(up-res)*DECDPUN; /* digits in top unit */ 675 for (c=cfirst;; c++) { /* along the digits */ 676 if (*c=='.') continue; /* ignore '.' [don't decrement cut] */ 677 out=X10(out)+(Int)*c-(Int)'0'; 678 if (c==last) break; /* done [never get to trailing '.'] */ 679 cut--; 680 if (cut>0) continue; /* more for this unit */ 681 *up=(Unit)out; /* write unit */ 682 up--; /* prepare for unit below.. */ 683 cut=DECDPUN; /* .. */ 684 out=0; /* .. */ 685 } /* c */ 686 *up=(Unit)out; /* write lsu */ 687 688 #else 689 /* DECDPUN==1 */ 690 up=res; /* -> lsu */ 691 for (c=last; c>=cfirst; c--) { /* over each character, from least */ 692 if (*c=='.') continue; /* ignore . [don't step up] */ 693 *up=(Unit)((Int)*c-(Int)'0'); 694 up++; 695 } /* c */ 696 #endif 697 698 dn->bits=bits; 699 dn->exponent=exponent; 700 dn->digits=d; 701 702 /* if not in number (too long) shorten into the number */ 703 if (d>set->digits) { 704 residue=0; 705 decSetCoeff(dn, set, res, d, &residue, &status); 706 /* always check for overflow or subnormal and round as needed */ 707 decFinalize(dn, set, &residue, &status); 708 } 709 else { /* no rounding, but may still have overflow or subnormal */ 710 /* [these tests are just for performance; finalize repeats them] */ 711 if ((dn->exponent-1<set->emin-dn->digits) 712 || (dn->exponent-1>set->emax-set->digits)) { 713 residue=0; 714 decFinalize(dn, set, &residue, &status); 715 } 716 } 717 /* decNumberShow(dn); */ 718 } while(0); /* [for break] */ 719 720 if (allocres!=NULL) free(allocres); /* drop any storage used */ 721 if (status!=0) decStatus(dn, status, set); 722 return dn; 723 } /* decNumberFromString */ 724 725 /* ================================================================== */ 726 /* Operators */ 727 /* ================================================================== */ 728 729 /* ------------------------------------------------------------------ */ 730 /* decNumberAbs -- absolute value operator */ 731 /* */ 732 /* This computes C = abs(A) */ 733 /* */ 734 /* res is C, the result. C may be A */ 735 /* rhs is A */ 736 /* set is the context */ 737 /* */ 738 /* See also decNumberCopyAbs for a quiet bitwise version of this. */ 739 /* C must have space for set->digits digits. */ 740 /* ------------------------------------------------------------------ */ 741 /* This has the same effect as decNumberPlus unless A is negative, */ 742 /* in which case it has the same effect as decNumberMinus. */ 743 /* ------------------------------------------------------------------ */ 744 U_CAPI decNumber * U_EXPORT2 uprv_decNumberAbs(decNumber *res, const decNumber *rhs, 745 decContext *set) { 746 decNumber dzero; /* for 0 */ 747 uInt status=0; /* accumulator */ 748 749 #if DECCHECK 750 if (decCheckOperands(res, DECUNUSED, rhs, set)) return res; 751 #endif 752 753 uprv_decNumberZero(&dzero); /* set 0 */ 754 dzero.exponent=rhs->exponent; /* [no coefficient expansion] */ 755 decAddOp(res, &dzero, rhs, set, (uByte)(rhs->bits & DECNEG), &status); 756 if (status!=0) decStatus(res, status, set); 757 #if DECCHECK 758 decCheckInexact(res, set); 759 #endif 760 return res; 761 } /* decNumberAbs */ 762 763 /* ------------------------------------------------------------------ */ 764 /* decNumberAdd -- add two Numbers */ 765 /* */ 766 /* This computes C = A + B */ 767 /* */ 768 /* res is C, the result. C may be A and/or B (e.g., X=X+X) */ 769 /* lhs is A */ 770 /* rhs is B */ 771 /* set is the context */ 772 /* */ 773 /* C must have space for set->digits digits. */ 774 /* ------------------------------------------------------------------ */ 775 /* This just calls the routine shared with Subtract */ 776 U_CAPI decNumber * U_EXPORT2 uprv_decNumberAdd(decNumber *res, const decNumber *lhs, 777 const decNumber *rhs, decContext *set) { 778 uInt status=0; /* accumulator */ 779 decAddOp(res, lhs, rhs, set, 0, &status); 780 if (status!=0) decStatus(res, status, set); 781 #if DECCHECK 782 decCheckInexact(res, set); 783 #endif 784 return res; 785 } /* decNumberAdd */ 786 787 /* ------------------------------------------------------------------ */ 788 /* decNumberAnd -- AND two Numbers, digitwise */ 789 /* */ 790 /* This computes C = A & B */ 791 /* */ 792 /* res is C, the result. C may be A and/or B (e.g., X=X&X) */ 793 /* lhs is A */ 794 /* rhs is B */ 795 /* set is the context (used for result length and error report) */ 796 /* */ 797 /* C must have space for set->digits digits. */ 798 /* */ 799 /* Logical function restrictions apply (see above); a NaN is */ 800 /* returned with Invalid_operation if a restriction is violated. */ 801 /* ------------------------------------------------------------------ */ 802 U_CAPI decNumber * U_EXPORT2 uprv_decNumberAnd(decNumber *res, const decNumber *lhs, 803 const decNumber *rhs, decContext *set) { 804 const Unit *ua, *ub; /* -> operands */ 805 const Unit *msua, *msub; /* -> operand msus */ 806 Unit *uc, *msuc; /* -> result and its msu */ 807 Int msudigs; /* digits in res msu */ 808 #if DECCHECK 809 if (decCheckOperands(res, lhs, rhs, set)) return res; 810 #endif 811 812 if (lhs->exponent!=0 || decNumberIsSpecial(lhs) || decNumberIsNegative(lhs) 813 || rhs->exponent!=0 || decNumberIsSpecial(rhs) || decNumberIsNegative(rhs)) { 814 decStatus(res, DEC_Invalid_operation, set); 815 return res; 816 } 817 818 /* operands are valid */ 819 ua=lhs->lsu; /* bottom-up */ 820 ub=rhs->lsu; /* .. */ 821 uc=res->lsu; /* .. */ 822 msua=ua+D2U(lhs->digits)-1; /* -> msu of lhs */ 823 msub=ub+D2U(rhs->digits)-1; /* -> msu of rhs */ 824 msuc=uc+D2U(set->digits)-1; /* -> msu of result */ 825 msudigs=MSUDIGITS(set->digits); /* [faster than remainder] */ 826 for (; uc<=msuc; ua++, ub++, uc++) { /* Unit loop */ 827 Unit a, b; /* extract units */ 828 if (ua>msua) a=0; 829 else a=*ua; 830 if (ub>msub) b=0; 831 else b=*ub; 832 *uc=0; /* can now write back */ 833 if (a|b) { /* maybe 1 bits to examine */ 834 Int i, j; 835 *uc=0; /* can now write back */ 836 /* This loop could be unrolled and/or use BIN2BCD tables */ 837 for (i=0; i<DECDPUN; i++) { 838 if (a&b&1) *uc=*uc+(Unit)powers[i]; /* effect AND */ 839 j=a%10; 840 a=a/10; 841 j|=b%10; 842 b=b/10; 843 if (j>1) { 844 decStatus(res, DEC_Invalid_operation, set); 845 return res; 846 } 847 if (uc==msuc && i==msudigs-1) break; /* just did final digit */ 848 } /* each digit */ 849 } /* both OK */ 850 } /* each unit */ 851 /* [here uc-1 is the msu of the result] */ 852 res->digits=decGetDigits(res->lsu, uc-res->lsu); 853 res->exponent=0; /* integer */ 854 res->bits=0; /* sign=0 */ 855 return res; /* [no status to set] */ 856 } /* decNumberAnd */ 857 858 /* ------------------------------------------------------------------ */ 859 /* decNumberCompare -- compare two Numbers */ 860 /* */ 861 /* This computes C = A ? B */ 862 /* */ 863 /* res is C, the result. C may be A and/or B (e.g., X=X?X) */ 864 /* lhs is A */ 865 /* rhs is B */ 866 /* set is the context */ 867 /* */ 868 /* C must have space for one digit (or NaN). */ 869 /* ------------------------------------------------------------------ */ 870 U_CAPI decNumber * U_EXPORT2 uprv_decNumberCompare(decNumber *res, const decNumber *lhs, 871 const decNumber *rhs, decContext *set) { 872 uInt status=0; /* accumulator */ 873 decCompareOp(res, lhs, rhs, set, COMPARE, &status); 874 if (status!=0) decStatus(res, status, set); 875 return res; 876 } /* decNumberCompare */ 877 878 /* ------------------------------------------------------------------ */ 879 /* decNumberCompareSignal -- compare, signalling on all NaNs */ 880 /* */ 881 /* This computes C = A ? B */ 882 /* */ 883 /* res is C, the result. C may be A and/or B (e.g., X=X?X) */ 884 /* lhs is A */ 885 /* rhs is B */ 886 /* set is the context */ 887 /* */ 888 /* C must have space for one digit (or NaN). */ 889 /* ------------------------------------------------------------------ */ 890 U_CAPI decNumber * U_EXPORT2 uprv_decNumberCompareSignal(decNumber *res, const decNumber *lhs, 891 const decNumber *rhs, decContext *set) { 892 uInt status=0; /* accumulator */ 893 decCompareOp(res, lhs, rhs, set, COMPSIG, &status); 894 if (status!=0) decStatus(res, status, set); 895 return res; 896 } /* decNumberCompareSignal */ 897 898 /* ------------------------------------------------------------------ */ 899 /* decNumberCompareTotal -- compare two Numbers, using total ordering */ 900 /* */ 901 /* This computes C = A ? B, under total ordering */ 902 /* */ 903 /* res is C, the result. C may be A and/or B (e.g., X=X?X) */ 904 /* lhs is A */ 905 /* rhs is B */ 906 /* set is the context */ 907 /* */ 908 /* C must have space for one digit; the result will always be one of */ 909 /* -1, 0, or 1. */ 910 /* ------------------------------------------------------------------ */ 911 U_CAPI decNumber * U_EXPORT2 uprv_decNumberCompareTotal(decNumber *res, const decNumber *lhs, 912 const decNumber *rhs, decContext *set) { 913 uInt status=0; /* accumulator */ 914 decCompareOp(res, lhs, rhs, set, COMPTOTAL, &status); 915 if (status!=0) decStatus(res, status, set); 916 return res; 917 } /* decNumberCompareTotal */ 918 919 /* ------------------------------------------------------------------ */ 920 /* decNumberCompareTotalMag -- compare, total ordering of magnitudes */ 921 /* */ 922 /* This computes C = |A| ? |B|, under total ordering */ 923 /* */ 924 /* res is C, the result. C may be A and/or B (e.g., X=X?X) */ 925 /* lhs is A */ 926 /* rhs is B */ 927 /* set is the context */ 928 /* */ 929 /* C must have space for one digit; the result will always be one of */ 930 /* -1, 0, or 1. */ 931 /* ------------------------------------------------------------------ */ 932 U_CAPI decNumber * U_EXPORT2 uprv_decNumberCompareTotalMag(decNumber *res, const decNumber *lhs, 933 const decNumber *rhs, decContext *set) { 934 uInt status=0; /* accumulator */ 935 uInt needbytes; /* for space calculations */ 936 decNumber bufa[D2N(DECBUFFER+1)];/* +1 in case DECBUFFER=0 */ 937 decNumber *allocbufa=NULL; /* -> allocated bufa, iff allocated */ 938 decNumber bufb[D2N(DECBUFFER+1)]; 939 decNumber *allocbufb=NULL; /* -> allocated bufb, iff allocated */ 940 decNumber *a, *b; /* temporary pointers */ 941 942 #if DECCHECK 943 if (decCheckOperands(res, lhs, rhs, set)) return res; 944 #endif 945 946 do { /* protect allocated storage */ 947 /* if either is negative, take a copy and absolute */ 948 if (decNumberIsNegative(lhs)) { /* lhs<0 */ 949 a=bufa; 950 needbytes=sizeof(decNumber)+(D2U(lhs->digits)-1)*sizeof(Unit); 951 if (needbytes>sizeof(bufa)) { /* need malloc space */ 952 allocbufa=(decNumber *)malloc(needbytes); 953 if (allocbufa==NULL) { /* hopeless -- abandon */ 954 status|=DEC_Insufficient_storage; 955 break;} 956 a=allocbufa; /* use the allocated space */ 957 } 958 uprv_decNumberCopy(a, lhs); /* copy content */ 959 a->bits&=~DECNEG; /* .. and clear the sign */ 960 lhs=a; /* use copy from here on */ 961 } 962 if (decNumberIsNegative(rhs)) { /* rhs<0 */ 963 b=bufb; 964 needbytes=sizeof(decNumber)+(D2U(rhs->digits)-1)*sizeof(Unit); 965 if (needbytes>sizeof(bufb)) { /* need malloc space */ 966 allocbufb=(decNumber *)malloc(needbytes); 967 if (allocbufb==NULL) { /* hopeless -- abandon */ 968 status|=DEC_Insufficient_storage; 969 break;} 970 b=allocbufb; /* use the allocated space */ 971 } 972 uprv_decNumberCopy(b, rhs); /* copy content */ 973 b->bits&=~DECNEG; /* .. and clear the sign */ 974 rhs=b; /* use copy from here on */ 975 } 976 decCompareOp(res, lhs, rhs, set, COMPTOTAL, &status); 977 } while(0); /* end protected */ 978 979 if (allocbufa!=NULL) free(allocbufa); /* drop any storage used */ 980 if (allocbufb!=NULL) free(allocbufb); /* .. */ 981 if (status!=0) decStatus(res, status, set); 982 return res; 983 } /* decNumberCompareTotalMag */ 984 985 /* ------------------------------------------------------------------ */ 986 /* decNumberDivide -- divide one number by another */ 987 /* */ 988 /* This computes C = A / B */ 989 /* */ 990 /* res is C, the result. C may be A and/or B (e.g., X=X/X) */ 991 /* lhs is A */ 992 /* rhs is B */ 993 /* set is the context */ 994 /* */ 995 /* C must have space for set->digits digits. */ 996 /* ------------------------------------------------------------------ */ 997 U_CAPI decNumber * U_EXPORT2 uprv_decNumberDivide(decNumber *res, const decNumber *lhs, 998 const decNumber *rhs, decContext *set) { 999 uInt status=0; /* accumulator */ 1000 decDivideOp(res, lhs, rhs, set, DIVIDE, &status); 1001 if (status!=0) decStatus(res, status, set); 1002 #if DECCHECK 1003 decCheckInexact(res, set); 1004 #endif 1005 return res; 1006 } /* decNumberDivide */ 1007 1008 /* ------------------------------------------------------------------ */ 1009 /* decNumberDivideInteger -- divide and return integer quotient */ 1010 /* */ 1011 /* This computes C = A # B, where # is the integer divide operator */ 1012 /* */ 1013 /* res is C, the result. C may be A and/or B (e.g., X=X#X) */ 1014 /* lhs is A */ 1015 /* rhs is B */ 1016 /* set is the context */ 1017 /* */ 1018 /* C must have space for set->digits digits. */ 1019 /* ------------------------------------------------------------------ */ 1020 U_CAPI decNumber * U_EXPORT2 uprv_decNumberDivideInteger(decNumber *res, const decNumber *lhs, 1021 const decNumber *rhs, decContext *set) { 1022 uInt status=0; /* accumulator */ 1023 decDivideOp(res, lhs, rhs, set, DIVIDEINT, &status); 1024 if (status!=0) decStatus(res, status, set); 1025 return res; 1026 } /* decNumberDivideInteger */ 1027 1028 /* ------------------------------------------------------------------ */ 1029 /* decNumberExp -- exponentiation */ 1030 /* */ 1031 /* This computes C = exp(A) */ 1032 /* */ 1033 /* res is C, the result. C may be A */ 1034 /* rhs is A */ 1035 /* set is the context; note that rounding mode has no effect */ 1036 /* */ 1037 /* C must have space for set->digits digits. */ 1038 /* */ 1039 /* Mathematical function restrictions apply (see above); a NaN is */ 1040 /* returned with Invalid_operation if a restriction is violated. */ 1041 /* */ 1042 /* Finite results will always be full precision and Inexact, except */ 1043 /* when A is a zero or -Infinity (giving 1 or 0 respectively). */ 1044 /* */ 1045 /* An Inexact result is rounded using DEC_ROUND_HALF_EVEN; it will */ 1046 /* almost always be correctly rounded, but may be up to 1 ulp in */ 1047 /* error in rare cases. */ 1048 /* ------------------------------------------------------------------ */ 1049 /* This is a wrapper for decExpOp which can handle the slightly wider */ 1050 /* (double) range needed by Ln (which has to be able to calculate */ 1051 /* exp(-a) where a can be the tiniest number (Ntiny). */ 1052 /* ------------------------------------------------------------------ */ 1053 U_CAPI decNumber * U_EXPORT2 uprv_decNumberExp(decNumber *res, const decNumber *rhs, 1054 decContext *set) { 1055 uInt status=0; /* accumulator */ 1056 #if DECSUBSET 1057 decNumber *allocrhs=NULL; /* non-NULL if rounded rhs allocated */ 1058 #endif 1059 1060 #if DECCHECK 1061 if (decCheckOperands(res, DECUNUSED, rhs, set)) return res; 1062 #endif 1063 1064 /* Check restrictions; these restrictions ensure that if h=8 (see */ 1065 /* decExpOp) then the result will either overflow or underflow to 0. */ 1066 /* Other math functions restrict the input range, too, for inverses. */ 1067 /* If not violated then carry out the operation. */ 1068 if (!decCheckMath(rhs, set, &status)) do { /* protect allocation */ 1069 #if DECSUBSET 1070 if (!set->extended) { 1071 /* reduce operand and set lostDigits status, as needed */ 1072 if (rhs->digits>set->digits) { 1073 allocrhs=decRoundOperand(rhs, set, &status); 1074 if (allocrhs==NULL) break; 1075 rhs=allocrhs; 1076 } 1077 } 1078 #endif 1079 decExpOp(res, rhs, set, &status); 1080 } while(0); /* end protected */ 1081 1082 #if DECSUBSET 1083 if (allocrhs !=NULL) free(allocrhs); /* drop any storage used */ 1084 #endif 1085 /* apply significant status */ 1086 if (status!=0) decStatus(res, status, set); 1087 #if DECCHECK 1088 decCheckInexact(res, set); 1089 #endif 1090 return res; 1091 } /* decNumberExp */ 1092 1093 /* ------------------------------------------------------------------ */ 1094 /* decNumberFMA -- fused multiply add */ 1095 /* */ 1096 /* This computes D = (A * B) + C with only one rounding */ 1097 /* */ 1098 /* res is D, the result. D may be A or B or C (e.g., X=FMA(X,X,X)) */ 1099 /* lhs is A */ 1100 /* rhs is B */ 1101 /* fhs is C [far hand side] */ 1102 /* set is the context */ 1103 /* */ 1104 /* Mathematical function restrictions apply (see above); a NaN is */ 1105 /* returned with Invalid_operation if a restriction is violated. */ 1106 /* */ 1107 /* C must have space for set->digits digits. */ 1108 /* ------------------------------------------------------------------ */ 1109 U_CAPI decNumber * U_EXPORT2 uprv_decNumberFMA(decNumber *res, const decNumber *lhs, 1110 const decNumber *rhs, const decNumber *fhs, 1111 decContext *set) { 1112 uInt status=0; /* accumulator */ 1113 decContext dcmul; /* context for the multiplication */ 1114 uInt needbytes; /* for space calculations */ 1115 decNumber bufa[D2N(DECBUFFER*2+1)]; 1116 decNumber *allocbufa=NULL; /* -> allocated bufa, iff allocated */ 1117 decNumber *acc; /* accumulator pointer */ 1118 decNumber dzero; /* work */ 1119 1120 #if DECCHECK 1121 if (decCheckOperands(res, lhs, rhs, set)) return res; 1122 if (decCheckOperands(res, fhs, DECUNUSED, set)) return res; 1123 #endif 1124 1125 do { /* protect allocated storage */ 1126 #if DECSUBSET 1127 if (!set->extended) { /* [undefined if subset] */ 1128 status|=DEC_Invalid_operation; 1129 break;} 1130 #endif 1131 /* Check math restrictions [these ensure no overflow or underflow] */ 1132 if ((!decNumberIsSpecial(lhs) && decCheckMath(lhs, set, &status)) 1133 || (!decNumberIsSpecial(rhs) && decCheckMath(rhs, set, &status)) 1134 || (!decNumberIsSpecial(fhs) && decCheckMath(fhs, set, &status))) break; 1135 /* set up context for multiply */ 1136 dcmul=*set; 1137 dcmul.digits=lhs->digits+rhs->digits; /* just enough */ 1138 /* [The above may be an over-estimate for subset arithmetic, but that's OK] */ 1139 dcmul.emax=DEC_MAX_EMAX; /* effectively unbounded .. */ 1140 dcmul.emin=DEC_MIN_EMIN; /* [thanks to Math restrictions] */ 1141 /* set up decNumber space to receive the result of the multiply */ 1142 acc=bufa; /* may fit */ 1143 needbytes=sizeof(decNumber)+(D2U(dcmul.digits)-1)*sizeof(Unit); 1144 if (needbytes>sizeof(bufa)) { /* need malloc space */ 1145 allocbufa=(decNumber *)malloc(needbytes); 1146 if (allocbufa==NULL) { /* hopeless -- abandon */ 1147 status|=DEC_Insufficient_storage; 1148 break;} 1149 acc=allocbufa; /* use the allocated space */ 1150 } 1151 /* multiply with extended range and necessary precision */ 1152 /*printf("emin=%ld\n", dcmul.emin); */ 1153 decMultiplyOp(acc, lhs, rhs, &dcmul, &status); 1154 /* Only Invalid operation (from sNaN or Inf * 0) is possible in */ 1155 /* status; if either is seen than ignore fhs (in case it is */ 1156 /* another sNaN) and set acc to NaN unless we had an sNaN */ 1157 /* [decMultiplyOp leaves that to caller] */ 1158 /* Note sNaN has to go through addOp to shorten payload if */ 1159 /* necessary */ 1160 if ((status&DEC_Invalid_operation)!=0) { 1161 if (!(status&DEC_sNaN)) { /* but be true invalid */ 1162 uprv_decNumberZero(res); /* acc not yet set */ 1163 res->bits=DECNAN; 1164 break; 1165 } 1166 uprv_decNumberZero(&dzero); /* make 0 (any non-NaN would do) */ 1167 fhs=&dzero; /* use that */ 1168 } 1169 #if DECCHECK 1170 else { /* multiply was OK */ 1171 if (status!=0) printf("Status=%08lx after FMA multiply\n", (LI)status); 1172 } 1173 #endif 1174 /* add the third operand and result -> res, and all is done */ 1175 decAddOp(res, acc, fhs, set, 0, &status); 1176 } while(0); /* end protected */ 1177 1178 if (allocbufa!=NULL) free(allocbufa); /* drop any storage used */ 1179 if (status!=0) decStatus(res, status, set); 1180 #if DECCHECK 1181 decCheckInexact(res, set); 1182 #endif 1183 return res; 1184 } /* decNumberFMA */ 1185 1186 /* ------------------------------------------------------------------ */ 1187 /* decNumberInvert -- invert a Number, digitwise */ 1188 /* */ 1189 /* This computes C = ~A */ 1190 /* */ 1191 /* res is C, the result. C may be A (e.g., X=~X) */ 1192 /* rhs is A */ 1193 /* set is the context (used for result length and error report) */ 1194 /* */ 1195 /* C must have space for set->digits digits. */ 1196 /* */ 1197 /* Logical function restrictions apply (see above); a NaN is */ 1198 /* returned with Invalid_operation if a restriction is violated. */ 1199 /* ------------------------------------------------------------------ */ 1200 U_CAPI decNumber * U_EXPORT2 uprv_decNumberInvert(decNumber *res, const decNumber *rhs, 1201 decContext *set) { 1202 const Unit *ua, *msua; /* -> operand and its msu */ 1203 Unit *uc, *msuc; /* -> result and its msu */ 1204 Int msudigs; /* digits in res msu */ 1205 #if DECCHECK 1206 if (decCheckOperands(res, DECUNUSED, rhs, set)) return res; 1207 #endif 1208 1209 if (rhs->exponent!=0 || decNumberIsSpecial(rhs) || decNumberIsNegative(rhs)) { 1210 decStatus(res, DEC_Invalid_operation, set); 1211 return res; 1212 } 1213 /* operand is valid */ 1214 ua=rhs->lsu; /* bottom-up */ 1215 uc=res->lsu; /* .. */ 1216 msua=ua+D2U(rhs->digits)-1; /* -> msu of rhs */ 1217 msuc=uc+D2U(set->digits)-1; /* -> msu of result */ 1218 msudigs=MSUDIGITS(set->digits); /* [faster than remainder] */ 1219 for (; uc<=msuc; ua++, uc++) { /* Unit loop */ 1220 Unit a; /* extract unit */ 1221 Int i, j; /* work */ 1222 if (ua>msua) a=0; 1223 else a=*ua; 1224 *uc=0; /* can now write back */ 1225 /* always need to examine all bits in rhs */ 1226 /* This loop could be unrolled and/or use BIN2BCD tables */ 1227 for (i=0; i<DECDPUN; i++) { 1228 if ((~a)&1) *uc=*uc+(Unit)powers[i]; /* effect INVERT */ 1229 j=a%10; 1230 a=a/10; 1231 if (j>1) { 1232 decStatus(res, DEC_Invalid_operation, set); 1233 return res; 1234 } 1235 if (uc==msuc && i==msudigs-1) break; /* just did final digit */ 1236 } /* each digit */ 1237 } /* each unit */ 1238 /* [here uc-1 is the msu of the result] */ 1239 res->digits=decGetDigits(res->lsu, uc-res->lsu); 1240 res->exponent=0; /* integer */ 1241 res->bits=0; /* sign=0 */ 1242 return res; /* [no status to set] */ 1243 } /* decNumberInvert */ 1244 1245 /* ------------------------------------------------------------------ */ 1246 /* decNumberLn -- natural logarithm */ 1247 /* */ 1248 /* This computes C = ln(A) */ 1249 /* */ 1250 /* res is C, the result. C may be A */ 1251 /* rhs is A */ 1252 /* set is the context; note that rounding mode has no effect */ 1253 /* */ 1254 /* C must have space for set->digits digits. */ 1255 /* */ 1256 /* Notable cases: */ 1257 /* A<0 -> Invalid */ 1258 /* A=0 -> -Infinity (Exact) */ 1259 /* A=+Infinity -> +Infinity (Exact) */ 1260 /* A=1 exactly -> 0 (Exact) */ 1261 /* */ 1262 /* Mathematical function restrictions apply (see above); a NaN is */ 1263 /* returned with Invalid_operation if a restriction is violated. */ 1264 /* */ 1265 /* An Inexact result is rounded using DEC_ROUND_HALF_EVEN; it will */ 1266 /* almost always be correctly rounded, but may be up to 1 ulp in */ 1267 /* error in rare cases. */ 1268 /* ------------------------------------------------------------------ */ 1269 /* This is a wrapper for decLnOp which can handle the slightly wider */ 1270 /* (+11) range needed by Ln, Log10, etc. (which may have to be able */ 1271 /* to calculate at p+e+2). */ 1272 /* ------------------------------------------------------------------ */ 1273 U_CAPI decNumber * U_EXPORT2 uprv_decNumberLn(decNumber *res, const decNumber *rhs, 1274 decContext *set) { 1275 uInt status=0; /* accumulator */ 1276 #if DECSUBSET 1277 decNumber *allocrhs=NULL; /* non-NULL if rounded rhs allocated */ 1278 #endif 1279 1280 #if DECCHECK 1281 if (decCheckOperands(res, DECUNUSED, rhs, set)) return res; 1282 #endif 1283 1284 /* Check restrictions; this is a math function; if not violated */ 1285 /* then carry out the operation. */ 1286 if (!decCheckMath(rhs, set, &status)) do { /* protect allocation */ 1287 #if DECSUBSET 1288 if (!set->extended) { 1289 /* reduce operand and set lostDigits status, as needed */ 1290 if (rhs->digits>set->digits) { 1291 allocrhs=decRoundOperand(rhs, set, &status); 1292 if (allocrhs==NULL) break; 1293 rhs=allocrhs; 1294 } 1295 /* special check in subset for rhs=0 */ 1296 if (ISZERO(rhs)) { /* +/- zeros -> error */ 1297 status|=DEC_Invalid_operation; 1298 break;} 1299 } /* extended=0 */ 1300 #endif 1301 decLnOp(res, rhs, set, &status); 1302 } while(0); /* end protected */ 1303 1304 #if DECSUBSET 1305 if (allocrhs !=NULL) free(allocrhs); /* drop any storage used */ 1306 #endif 1307 /* apply significant status */ 1308 if (status!=0) decStatus(res, status, set); 1309 #if DECCHECK 1310 decCheckInexact(res, set); 1311 #endif 1312 return res; 1313 } /* decNumberLn */ 1314 1315 /* ------------------------------------------------------------------ */ 1316 /* decNumberLogB - get adjusted exponent, by 754 rules */ 1317 /* */ 1318 /* This computes C = adjustedexponent(A) */ 1319 /* */ 1320 /* res is C, the result. C may be A */ 1321 /* rhs is A */ 1322 /* set is the context, used only for digits and status */ 1323 /* */ 1324 /* C must have space for 10 digits (A might have 10**9 digits and */ 1325 /* an exponent of +999999999, or one digit and an exponent of */ 1326 /* -1999999999). */ 1327 /* */ 1328 /* This returns the adjusted exponent of A after (in theory) padding */ 1329 /* with zeros on the right to set->digits digits while keeping the */ 1330 /* same value. The exponent is not limited by emin/emax. */ 1331 /* */ 1332 /* Notable cases: */ 1333 /* A<0 -> Use |A| */ 1334 /* A=0 -> -Infinity (Division by zero) */ 1335 /* A=Infinite -> +Infinity (Exact) */ 1336 /* A=1 exactly -> 0 (Exact) */ 1337 /* NaNs are propagated as usual */ 1338 /* ------------------------------------------------------------------ */ 1339 U_CAPI decNumber * U_EXPORT2 uprv_decNumberLogB(decNumber *res, const decNumber *rhs, 1340 decContext *set) { 1341 uInt status=0; /* accumulator */ 1342 1343 #if DECCHECK 1344 if (decCheckOperands(res, DECUNUSED, rhs, set)) return res; 1345 #endif 1346 1347 /* NaNs as usual; Infinities return +Infinity; 0->oops */ 1348 if (decNumberIsNaN(rhs)) decNaNs(res, rhs, NULL, set, &status); 1349 else if (decNumberIsInfinite(rhs)) uprv_decNumberCopyAbs(res, rhs); 1350 else if (decNumberIsZero(rhs)) { 1351 uprv_decNumberZero(res); /* prepare for Infinity */ 1352 res->bits=DECNEG|DECINF; /* -Infinity */ 1353 status|=DEC_Division_by_zero; /* as per 754 */ 1354 } 1355 else { /* finite non-zero */ 1356 Int ae=rhs->exponent+rhs->digits-1; /* adjusted exponent */ 1357 uprv_decNumberFromInt32(res, ae); /* lay it out */ 1358 } 1359 1360 if (status!=0) decStatus(res, status, set); 1361 return res; 1362 } /* decNumberLogB */ 1363 1364 /* ------------------------------------------------------------------ */ 1365 /* decNumberLog10 -- logarithm in base 10 */ 1366 /* */ 1367 /* This computes C = log10(A) */ 1368 /* */ 1369 /* res is C, the result. C may be A */ 1370 /* rhs is A */ 1371 /* set is the context; note that rounding mode has no effect */ 1372 /* */ 1373 /* C must have space for set->digits digits. */ 1374 /* */ 1375 /* Notable cases: */ 1376 /* A<0 -> Invalid */ 1377 /* A=0 -> -Infinity (Exact) */ 1378 /* A=+Infinity -> +Infinity (Exact) */ 1379 /* A=10**n (if n is an integer) -> n (Exact) */ 1380 /* */ 1381 /* Mathematical function restrictions apply (see above); a NaN is */ 1382 /* returned with Invalid_operation if a restriction is violated. */ 1383 /* */ 1384 /* An Inexact result is rounded using DEC_ROUND_HALF_EVEN; it will */ 1385 /* almost always be correctly rounded, but may be up to 1 ulp in */ 1386 /* error in rare cases. */ 1387 /* ------------------------------------------------------------------ */ 1388 /* This calculates ln(A)/ln(10) using appropriate precision. For */ 1389 /* ln(A) this is the max(p, rhs->digits + t) + 3, where p is the */ 1390 /* requested digits and t is the number of digits in the exponent */ 1391 /* (maximum 6). For ln(10) it is p + 3; this is often handled by the */ 1392 /* fastpath in decLnOp. The final division is done to the requested */ 1393 /* precision. */ 1394 /* ------------------------------------------------------------------ */ 1395 U_CAPI decNumber * U_EXPORT2 uprv_decNumberLog10(decNumber *res, const decNumber *rhs, 1396 decContext *set) { 1397 uInt status=0, ignore=0; /* status accumulators */ 1398 uInt needbytes; /* for space calculations */ 1399 Int p; /* working precision */ 1400 Int t; /* digits in exponent of A */ 1401 1402 /* buffers for a and b working decimals */ 1403 /* (adjustment calculator, same size) */ 1404 decNumber bufa[D2N(DECBUFFER+2)]; 1405 decNumber *allocbufa=NULL; /* -> allocated bufa, iff allocated */ 1406 decNumber *a=bufa; /* temporary a */ 1407 decNumber bufb[D2N(DECBUFFER+2)]; 1408 decNumber *allocbufb=NULL; /* -> allocated bufb, iff allocated */ 1409 decNumber *b=bufb; /* temporary b */ 1410 decNumber bufw[D2N(10)]; /* working 2-10 digit number */ 1411 decNumber *w=bufw; /* .. */ 1412 #if DECSUBSET 1413 decNumber *allocrhs=NULL; /* non-NULL if rounded rhs allocated */ 1414 #endif 1415 1416 decContext aset; /* working context */ 1417 1418 #if DECCHECK 1419 if (decCheckOperands(res, DECUNUSED, rhs, set)) return res; 1420 #endif 1421 1422 /* Check restrictions; this is a math function; if not violated */ 1423 /* then carry out the operation. */ 1424 if (!decCheckMath(rhs, set, &status)) do { /* protect malloc */ 1425 #if DECSUBSET 1426 if (!set->extended) { 1427 /* reduce operand and set lostDigits status, as needed */ 1428 if (rhs->digits>set->digits) { 1429 allocrhs=decRoundOperand(rhs, set, &status); 1430 if (allocrhs==NULL) break; 1431 rhs=allocrhs; 1432 } 1433 /* special check in subset for rhs=0 */ 1434 if (ISZERO(rhs)) { /* +/- zeros -> error */ 1435 status|=DEC_Invalid_operation; 1436 break;} 1437 } /* extended=0 */ 1438 #endif 1439 1440 uprv_decContextDefault(&aset, DEC_INIT_DECIMAL64); /* clean context */ 1441 1442 /* handle exact powers of 10; only check if +ve finite */ 1443 if (!(rhs->bits&(DECNEG|DECSPECIAL)) && !ISZERO(rhs)) { 1444 Int residue=0; /* (no residue) */ 1445 uInt copystat=0; /* clean status */ 1446 1447 /* round to a single digit... */ 1448 aset.digits=1; 1449 decCopyFit(w, rhs, &aset, &residue, ©stat); /* copy & shorten */ 1450 /* if exact and the digit is 1, rhs is a power of 10 */ 1451 if (!(copystat&DEC_Inexact) && w->lsu[0]==1) { 1452 /* the exponent, conveniently, is the power of 10; making */ 1453 /* this the result needs a little care as it might not fit, */ 1454 /* so first convert it into the working number, and then move */ 1455 /* to res */ 1456 uprv_decNumberFromInt32(w, w->exponent); 1457 residue=0; 1458 decCopyFit(res, w, set, &residue, &status); /* copy & round */ 1459 decFinish(res, set, &residue, &status); /* cleanup/set flags */ 1460 break; 1461 } /* not a power of 10 */ 1462 } /* not a candidate for exact */ 1463 1464 /* simplify the information-content calculation to use 'total */ 1465 /* number of digits in a, including exponent' as compared to the */ 1466 /* requested digits, as increasing this will only rarely cost an */ 1467 /* iteration in ln(a) anyway */ 1468 t=6; /* it can never be >6 */ 1469 1470 /* allocate space when needed... */ 1471 p=(rhs->digits+t>set->digits?rhs->digits+t:set->digits)+3; 1472 needbytes=sizeof(decNumber)+(D2U(p)-1)*sizeof(Unit); 1473 if (needbytes>sizeof(bufa)) { /* need malloc space */ 1474 allocbufa=(decNumber *)malloc(needbytes); 1475 if (allocbufa==NULL) { /* hopeless -- abandon */ 1476 status|=DEC_Insufficient_storage; 1477 break;} 1478 a=allocbufa; /* use the allocated space */ 1479 } 1480 aset.digits=p; /* as calculated */ 1481 aset.emax=DEC_MAX_MATH; /* usual bounds */ 1482 aset.emin=-DEC_MAX_MATH; /* .. */ 1483 aset.clamp=0; /* and no concrete format */ 1484 decLnOp(a, rhs, &aset, &status); /* a=ln(rhs) */ 1485 1486 /* skip the division if the result so far is infinite, NaN, or */ 1487 /* zero, or there was an error; note NaN from sNaN needs copy */ 1488 if (status&DEC_NaNs && !(status&DEC_sNaN)) break; 1489 if (a->bits&DECSPECIAL || ISZERO(a)) { 1490 uprv_decNumberCopy(res, a); /* [will fit] */ 1491 break;} 1492 1493 /* for ln(10) an extra 3 digits of precision are needed */ 1494 p=set->digits+3; 1495 needbytes=sizeof(decNumber)+(D2U(p)-1)*sizeof(Unit); 1496 if (needbytes>sizeof(bufb)) { /* need malloc space */ 1497 allocbufb=(decNumber *)malloc(needbytes); 1498 if (allocbufb==NULL) { /* hopeless -- abandon */ 1499 status|=DEC_Insufficient_storage; 1500 break;} 1501 b=allocbufb; /* use the allocated space */ 1502 } 1503 uprv_decNumberZero(w); /* set up 10... */ 1504 #if DECDPUN==1 1505 w->lsu[1]=1; w->lsu[0]=0; /* .. */ 1506 #else 1507 w->lsu[0]=10; /* .. */ 1508 #endif 1509 w->digits=2; /* .. */ 1510 1511 aset.digits=p; 1512 decLnOp(b, w, &aset, &ignore); /* b=ln(10) */ 1513 1514 aset.digits=set->digits; /* for final divide */ 1515 decDivideOp(res, a, b, &aset, DIVIDE, &status); /* into result */ 1516 } while(0); /* [for break] */ 1517 1518 if (allocbufa!=NULL) free(allocbufa); /* drop any storage used */ 1519 if (allocbufb!=NULL) free(allocbufb); /* .. */ 1520 #if DECSUBSET 1521 if (allocrhs !=NULL) free(allocrhs); /* .. */ 1522 #endif 1523 /* apply significant status */ 1524 if (status!=0) decStatus(res, status, set); 1525 #if DECCHECK 1526 decCheckInexact(res, set); 1527 #endif 1528 return res; 1529 } /* decNumberLog10 */ 1530 1531 /* ------------------------------------------------------------------ */ 1532 /* decNumberMax -- compare two Numbers and return the maximum */ 1533 /* */ 1534 /* This computes C = A ? B, returning the maximum by 754 rules */ 1535 /* */ 1536 /* res is C, the result. C may be A and/or B (e.g., X=X?X) */ 1537 /* lhs is A */ 1538 /* rhs is B */ 1539 /* set is the context */ 1540 /* */ 1541 /* C must have space for set->digits digits. */ 1542 /* ------------------------------------------------------------------ */ 1543 U_CAPI decNumber * U_EXPORT2 uprv_decNumberMax(decNumber *res, const decNumber *lhs, 1544 const decNumber *rhs, decContext *set) { 1545 uInt status=0; /* accumulator */ 1546 decCompareOp(res, lhs, rhs, set, COMPMAX, &status); 1547 if (status!=0) decStatus(res, status, set); 1548 #if DECCHECK 1549 decCheckInexact(res, set); 1550 #endif 1551 return res; 1552 } /* decNumberMax */ 1553 1554 /* ------------------------------------------------------------------ */ 1555 /* decNumberMaxMag -- compare and return the maximum by magnitude */ 1556 /* */ 1557 /* This computes C = A ? B, returning the maximum by 754 rules */ 1558 /* */ 1559 /* res is C, the result. C may be A and/or B (e.g., X=X?X) */ 1560 /* lhs is A */ 1561 /* rhs is B */ 1562 /* set is the context */ 1563 /* */ 1564 /* C must have space for set->digits digits. */ 1565 /* ------------------------------------------------------------------ */ 1566 U_CAPI decNumber * U_EXPORT2 uprv_decNumberMaxMag(decNumber *res, const decNumber *lhs, 1567 const decNumber *rhs, decContext *set) { 1568 uInt status=0; /* accumulator */ 1569 decCompareOp(res, lhs, rhs, set, COMPMAXMAG, &status); 1570 if (status!=0) decStatus(res, status, set); 1571 #if DECCHECK 1572 decCheckInexact(res, set); 1573 #endif 1574 return res; 1575 } /* decNumberMaxMag */ 1576 1577 /* ------------------------------------------------------------------ */ 1578 /* decNumberMin -- compare two Numbers and return the minimum */ 1579 /* */ 1580 /* This computes C = A ? B, returning the minimum by 754 rules */ 1581 /* */ 1582 /* res is C, the result. C may be A and/or B (e.g., X=X?X) */ 1583 /* lhs is A */ 1584 /* rhs is B */ 1585 /* set is the context */ 1586 /* */ 1587 /* C must have space for set->digits digits. */ 1588 /* ------------------------------------------------------------------ */ 1589 U_CAPI decNumber * U_EXPORT2 uprv_decNumberMin(decNumber *res, const decNumber *lhs, 1590 const decNumber *rhs, decContext *set) { 1591 uInt status=0; /* accumulator */ 1592 decCompareOp(res, lhs, rhs, set, COMPMIN, &status); 1593 if (status!=0) decStatus(res, status, set); 1594 #if DECCHECK 1595 decCheckInexact(res, set); 1596 #endif 1597 return res; 1598 } /* decNumberMin */ 1599 1600 /* ------------------------------------------------------------------ */ 1601 /* decNumberMinMag -- compare and return the minimum by magnitude */ 1602 /* */ 1603 /* This computes C = A ? B, returning the minimum by 754 rules */ 1604 /* */ 1605 /* res is C, the result. C may be A and/or B (e.g., X=X?X) */ 1606 /* lhs is A */ 1607 /* rhs is B */ 1608 /* set is the context */ 1609 /* */ 1610 /* C must have space for set->digits digits. */ 1611 /* ------------------------------------------------------------------ */ 1612 U_CAPI decNumber * U_EXPORT2 uprv_decNumberMinMag(decNumber *res, const decNumber *lhs, 1613 const decNumber *rhs, decContext *set) { 1614 uInt status=0; /* accumulator */ 1615 decCompareOp(res, lhs, rhs, set, COMPMINMAG, &status); 1616 if (status!=0) decStatus(res, status, set); 1617 #if DECCHECK 1618 decCheckInexact(res, set); 1619 #endif 1620 return res; 1621 } /* decNumberMinMag */ 1622 1623 /* ------------------------------------------------------------------ */ 1624 /* decNumberMinus -- prefix minus operator */ 1625 /* */ 1626 /* This computes C = 0 - A */ 1627 /* */ 1628 /* res is C, the result. C may be A */ 1629 /* rhs is A */ 1630 /* set is the context */ 1631 /* */ 1632 /* See also decNumberCopyNegate for a quiet bitwise version of this. */ 1633 /* C must have space for set->digits digits. */ 1634 /* ------------------------------------------------------------------ */ 1635 /* Simply use AddOp for the subtract, which will do the necessary. */ 1636 /* ------------------------------------------------------------------ */ 1637 U_CAPI decNumber * U_EXPORT2 uprv_decNumberMinus(decNumber *res, const decNumber *rhs, 1638 decContext *set) { 1639 decNumber dzero; 1640 uInt status=0; /* accumulator */ 1641 1642 #if DECCHECK 1643 if (decCheckOperands(res, DECUNUSED, rhs, set)) return res; 1644 #endif 1645 1646 uprv_decNumberZero(&dzero); /* make 0 */ 1647 dzero.exponent=rhs->exponent; /* [no coefficient expansion] */ 1648 decAddOp(res, &dzero, rhs, set, DECNEG, &status); 1649 if (status!=0) decStatus(res, status, set); 1650 #if DECCHECK 1651 decCheckInexact(res, set); 1652 #endif 1653 return res; 1654 } /* decNumberMinus */ 1655 1656 /* ------------------------------------------------------------------ */ 1657 /* decNumberNextMinus -- next towards -Infinity */ 1658 /* */ 1659 /* This computes C = A - infinitesimal, rounded towards -Infinity */ 1660 /* */ 1661 /* res is C, the result. C may be A */ 1662 /* rhs is A */ 1663 /* set is the context */ 1664 /* */ 1665 /* This is a generalization of 754 NextDown. */ 1666 /* ------------------------------------------------------------------ */ 1667 U_CAPI decNumber * U_EXPORT2 uprv_decNumberNextMinus(decNumber *res, const decNumber *rhs, 1668 decContext *set) { 1669 decNumber dtiny; /* constant */ 1670 decContext workset=*set; /* work */ 1671 uInt status=0; /* accumulator */ 1672 #if DECCHECK 1673 if (decCheckOperands(res, DECUNUSED, rhs, set)) return res; 1674 #endif 1675 1676 /* +Infinity is the special case */ 1677 if ((rhs->bits&(DECINF|DECNEG))==DECINF) { 1678 decSetMaxValue(res, set); /* is +ve */ 1679 /* there is no status to set */ 1680 return res; 1681 } 1682 uprv_decNumberZero(&dtiny); /* start with 0 */ 1683 dtiny.lsu[0]=1; /* make number that is .. */ 1684 dtiny.exponent=DEC_MIN_EMIN-1; /* .. smaller than tiniest */ 1685 workset.round=DEC_ROUND_FLOOR; 1686 decAddOp(res, rhs, &dtiny, &workset, DECNEG, &status); 1687 status&=DEC_Invalid_operation|DEC_sNaN; /* only sNaN Invalid please */ 1688 if (status!=0) decStatus(res, status, set); 1689 return res; 1690 } /* decNumberNextMinus */ 1691 1692 /* ------------------------------------------------------------------ */ 1693 /* decNumberNextPlus -- next towards +Infinity */ 1694 /* */ 1695 /* This computes C = A + infinitesimal, rounded towards +Infinity */ 1696 /* */ 1697 /* res is C, the result. C may be A */ 1698 /* rhs is A */ 1699 /* set is the context */ 1700 /* */ 1701 /* This is a generalization of 754 NextUp. */ 1702 /* ------------------------------------------------------------------ */ 1703 U_CAPI decNumber * U_EXPORT2 uprv_decNumberNextPlus(decNumber *res, const decNumber *rhs, 1704 decContext *set) { 1705 decNumber dtiny; /* constant */ 1706 decContext workset=*set; /* work */ 1707 uInt status=0; /* accumulator */ 1708 #if DECCHECK 1709 if (decCheckOperands(res, DECUNUSED, rhs, set)) return res; 1710 #endif 1711 1712 /* -Infinity is the special case */ 1713 if ((rhs->bits&(DECINF|DECNEG))==(DECINF|DECNEG)) { 1714 decSetMaxValue(res, set); 1715 res->bits=DECNEG; /* negative */ 1716 /* there is no status to set */ 1717 return res; 1718 } 1719 uprv_decNumberZero(&dtiny); /* start with 0 */ 1720 dtiny.lsu[0]=1; /* make number that is .. */ 1721 dtiny.exponent=DEC_MIN_EMIN-1; /* .. smaller than tiniest */ 1722 workset.round=DEC_ROUND_CEILING; 1723 decAddOp(res, rhs, &dtiny, &workset, 0, &status); 1724 status&=DEC_Invalid_operation|DEC_sNaN; /* only sNaN Invalid please */ 1725 if (status!=0) decStatus(res, status, set); 1726 return res; 1727 } /* decNumberNextPlus */ 1728 1729 /* ------------------------------------------------------------------ */ 1730 /* decNumberNextToward -- next towards rhs */ 1731 /* */ 1732 /* This computes C = A +/- infinitesimal, rounded towards */ 1733 /* +/-Infinity in the direction of B, as per 754-1985 nextafter */ 1734 /* modified during revision but dropped from 754-2008. */ 1735 /* */ 1736 /* res is C, the result. C may be A or B. */ 1737 /* lhs is A */ 1738 /* rhs is B */ 1739 /* set is the context */ 1740 /* */ 1741 /* This is a generalization of 754-1985 NextAfter. */ 1742 /* ------------------------------------------------------------------ */ 1743 U_CAPI decNumber * U_EXPORT2 uprv_decNumberNextToward(decNumber *res, const decNumber *lhs, 1744 const decNumber *rhs, decContext *set) { 1745 decNumber dtiny; /* constant */ 1746 decContext workset=*set; /* work */ 1747 Int result; /* .. */ 1748 uInt status=0; /* accumulator */ 1749 #if DECCHECK 1750 if (decCheckOperands(res, lhs, rhs, set)) return res; 1751 #endif 1752 1753 if (decNumberIsNaN(lhs) || decNumberIsNaN(rhs)) { 1754 decNaNs(res, lhs, rhs, set, &status); 1755 } 1756 else { /* Is numeric, so no chance of sNaN Invalid, etc. */ 1757 result=decCompare(lhs, rhs, 0); /* sign matters */ 1758 if (result==BADINT) status|=DEC_Insufficient_storage; /* rare */ 1759 else { /* valid compare */ 1760 if (result==0) uprv_decNumberCopySign(res, lhs, rhs); /* easy */ 1761 else { /* differ: need NextPlus or NextMinus */ 1762 uByte sub; /* add or subtract */ 1763 if (result<0) { /* lhs<rhs, do nextplus */ 1764 /* -Infinity is the special case */ 1765 if ((lhs->bits&(DECINF|DECNEG))==(DECINF|DECNEG)) { 1766 decSetMaxValue(res, set); 1767 res->bits=DECNEG; /* negative */ 1768 return res; /* there is no status to set */ 1769 } 1770 workset.round=DEC_ROUND_CEILING; 1771 sub=0; /* add, please */ 1772 } /* plus */ 1773 else { /* lhs>rhs, do nextminus */ 1774 /* +Infinity is the special case */ 1775 if ((lhs->bits&(DECINF|DECNEG))==DECINF) { 1776 decSetMaxValue(res, set); 1777 return res; /* there is no status to set */ 1778 } 1779 workset.round=DEC_ROUND_FLOOR; 1780 sub=DECNEG; /* subtract, please */ 1781 } /* minus */ 1782 uprv_decNumberZero(&dtiny); /* start with 0 */ 1783 dtiny.lsu[0]=1; /* make number that is .. */ 1784 dtiny.exponent=DEC_MIN_EMIN-1; /* .. smaller than tiniest */ 1785 decAddOp(res, lhs, &dtiny, &workset, sub, &status); /* + or - */ 1786 /* turn off exceptions if the result is a normal number */ 1787 /* (including Nmin), otherwise let all status through */ 1788 if (uprv_decNumberIsNormal(res, set)) status=0; 1789 } /* unequal */ 1790 } /* compare OK */ 1791 } /* numeric */ 1792 if (status!=0) decStatus(res, status, set); 1793 return res; 1794 } /* decNumberNextToward */ 1795 1796 /* ------------------------------------------------------------------ */ 1797 /* decNumberOr -- OR two Numbers, digitwise */ 1798 /* */ 1799 /* This computes C = A | B */ 1800 /* */ 1801 /* res is C, the result. C may be A and/or B (e.g., X=X|X) */ 1802 /* lhs is A */ 1803 /* rhs is B */ 1804 /* set is the context (used for result length and error report) */ 1805 /* */ 1806 /* C must have space for set->digits digits. */ 1807 /* */ 1808 /* Logical function restrictions apply (see above); a NaN is */ 1809 /* returned with Invalid_operation if a restriction is violated. */ 1810 /* ------------------------------------------------------------------ */ 1811 U_CAPI decNumber * U_EXPORT2 uprv_decNumberOr(decNumber *res, const decNumber *lhs, 1812 const decNumber *rhs, decContext *set) { 1813 const Unit *ua, *ub; /* -> operands */ 1814 const Unit *msua, *msub; /* -> operand msus */ 1815 Unit *uc, *msuc; /* -> result and its msu */ 1816 Int msudigs; /* digits in res msu */ 1817 #if DECCHECK 1818 if (decCheckOperands(res, lhs, rhs, set)) return res; 1819 #endif 1820 1821 if (lhs->exponent!=0 || decNumberIsSpecial(lhs) || decNumberIsNegative(lhs) 1822 || rhs->exponent!=0 || decNumberIsSpecial(rhs) || decNumberIsNegative(rhs)) { 1823 decStatus(res, DEC_Invalid_operation, set); 1824 return res; 1825 } 1826 /* operands are valid */ 1827 ua=lhs->lsu; /* bottom-up */ 1828 ub=rhs->lsu; /* .. */ 1829 uc=res->lsu; /* .. */ 1830 msua=ua+D2U(lhs->digits)-1; /* -> msu of lhs */ 1831 msub=ub+D2U(rhs->digits)-1; /* -> msu of rhs */ 1832 msuc=uc+D2U(set->digits)-1; /* -> msu of result */ 1833 msudigs=MSUDIGITS(set->digits); /* [faster than remainder] */ 1834 for (; uc<=msuc; ua++, ub++, uc++) { /* Unit loop */ 1835 Unit a, b; /* extract units */ 1836 if (ua>msua) a=0; 1837 else a=*ua; 1838 if (ub>msub) b=0; 1839 else b=*ub; 1840 *uc=0; /* can now write back */ 1841 if (a|b) { /* maybe 1 bits to examine */ 1842 Int i, j; 1843 /* This loop could be unrolled and/or use BIN2BCD tables */ 1844 for (i=0; i<DECDPUN; i++) { 1845 if ((a|b)&1) *uc=*uc+(Unit)powers[i]; /* effect OR */ 1846 j=a%10; 1847 a=a/10; 1848 j|=b%10; 1849 b=b/10; 1850 if (j>1) { 1851 decStatus(res, DEC_Invalid_operation, set); 1852 return res; 1853 } 1854 if (uc==msuc && i==msudigs-1) break; /* just did final digit */ 1855 } /* each digit */ 1856 } /* non-zero */ 1857 } /* each unit */ 1858 /* [here uc-1 is the msu of the result] */ 1859 res->digits=decGetDigits(res->lsu, uc-res->lsu); 1860 res->exponent=0; /* integer */ 1861 res->bits=0; /* sign=0 */ 1862 return res; /* [no status to set] */ 1863 } /* decNumberOr */ 1864 1865 /* ------------------------------------------------------------------ */ 1866 /* decNumberPlus -- prefix plus operator */ 1867 /* */ 1868 /* This computes C = 0 + A */ 1869 /* */ 1870 /* res is C, the result. C may be A */ 1871 /* rhs is A */ 1872 /* set is the context */ 1873 /* */ 1874 /* See also decNumberCopy for a quiet bitwise version of this. */ 1875 /* C must have space for set->digits digits. */ 1876 /* ------------------------------------------------------------------ */ 1877 /* This simply uses AddOp; Add will take fast path after preparing A. */ 1878 /* Performance is a concern here, as this routine is often used to */ 1879 /* check operands and apply rounding and overflow/underflow testing. */ 1880 /* ------------------------------------------------------------------ */ 1881 U_CAPI decNumber * U_EXPORT2 uprv_decNumberPlus(decNumber *res, const decNumber *rhs, 1882 decContext *set) { 1883 decNumber dzero; 1884 uInt status=0; /* accumulator */ 1885 #if DECCHECK 1886 if (decCheckOperands(res, DECUNUSED, rhs, set)) return res; 1887 #endif 1888 1889 uprv_decNumberZero(&dzero); /* make 0 */ 1890 dzero.exponent=rhs->exponent; /* [no coefficient expansion] */ 1891 decAddOp(res, &dzero, rhs, set, 0, &status); 1892 if (status!=0) decStatus(res, status, set); 1893 #if DECCHECK 1894 decCheckInexact(res, set); 1895 #endif 1896 return res; 1897 } /* decNumberPlus */ 1898 1899 /* ------------------------------------------------------------------ */ 1900 /* decNumberMultiply -- multiply two Numbers */ 1901 /* */ 1902 /* This computes C = A x B */ 1903 /* */ 1904 /* res is C, the result. C may be A and/or B (e.g., X=X+X) */ 1905 /* lhs is A */ 1906 /* rhs is B */ 1907 /* set is the context */ 1908 /* */ 1909 /* C must have space for set->digits digits. */ 1910 /* ------------------------------------------------------------------ */ 1911 U_CAPI decNumber * U_EXPORT2 uprv_decNumberMultiply(decNumber *res, const decNumber *lhs, 1912 const decNumber *rhs, decContext *set) { 1913 uInt status=0; /* accumulator */ 1914 decMultiplyOp(res, lhs, rhs, set, &status); 1915 if (status!=0) decStatus(res, status, set); 1916 #if DECCHECK 1917 decCheckInexact(res, set); 1918 #endif 1919 return res; 1920 } /* decNumberMultiply */ 1921 1922 /* ------------------------------------------------------------------ */ 1923 /* decNumberPower -- raise a number to a power */ 1924 /* */ 1925 /* This computes C = A ** B */ 1926 /* */ 1927 /* res is C, the result. C may be A and/or B (e.g., X=X**X) */ 1928 /* lhs is A */ 1929 /* rhs is B */ 1930 /* set is the context */ 1931 /* */ 1932 /* C must have space for set->digits digits. */ 1933 /* */ 1934 /* Mathematical function restrictions apply (see above); a NaN is */ 1935 /* returned with Invalid_operation if a restriction is violated. */ 1936 /* */ 1937 /* However, if 1999999997<=B<=999999999 and B is an integer then the */ 1938 /* restrictions on A and the context are relaxed to the usual bounds, */ 1939 /* for compatibility with the earlier (integer power only) version */ 1940 /* of this function. */ 1941 /* */ 1942 /* When B is an integer, the result may be exact, even if rounded. */ 1943 /* */ 1944 /* The final result is rounded according to the context; it will */ 1945 /* almost always be correctly rounded, but may be up to 1 ulp in */ 1946 /* error in rare cases. */ 1947 /* ------------------------------------------------------------------ */ 1948 U_CAPI decNumber * U_EXPORT2 uprv_decNumberPower(decNumber *res, const decNumber *lhs, 1949 const decNumber *rhs, decContext *set) { 1950 #if DECSUBSET 1951 decNumber *alloclhs=NULL; /* non-NULL if rounded lhs allocated */ 1952 decNumber *allocrhs=NULL; /* .., rhs */ 1953 #endif 1954 decNumber *allocdac=NULL; /* -> allocated acc buffer, iff used */ 1955 decNumber *allocinv=NULL; /* -> allocated 1/x buffer, iff used */ 1956 Int reqdigits=set->digits; /* requested DIGITS */ 1957 Int n; /* rhs in binary */ 1958 Flag rhsint=0; /* 1 if rhs is an integer */ 1959 Flag useint=0; /* 1 if can use integer calculation */ 1960 Flag isoddint=0; /* 1 if rhs is an integer and odd */ 1961 Int i; /* work */ 1962 #if DECSUBSET 1963 Int dropped; /* .. */ 1964 #endif 1965 uInt needbytes; /* buffer size needed */ 1966 Flag seenbit; /* seen a bit while powering */ 1967 Int residue=0; /* rounding residue */ 1968 uInt status=0; /* accumulators */ 1969 uByte bits=0; /* result sign if errors */ 1970 decContext aset; /* working context */ 1971 decNumber dnOne; /* work value 1... */ 1972 /* local accumulator buffer [a decNumber, with digits+elength+1 digits] */ 1973 decNumber dacbuff[D2N(DECBUFFER+9)]; 1974 decNumber *dac=dacbuff; /* -> result accumulator */ 1975 /* same again for possible 1/lhs calculation */ 1976 decNumber invbuff[D2N(DECBUFFER+9)]; 1977 1978 #if DECCHECK 1979 if (decCheckOperands(res, lhs, rhs, set)) return res; 1980 #endif 1981 1982 do { /* protect allocated storage */ 1983 #if DECSUBSET 1984 if (!set->extended) { /* reduce operands and set status, as needed */ 1985 if (lhs->digits>reqdigits) { 1986 alloclhs=decRoundOperand(lhs, set, &status); 1987 if (alloclhs==NULL) break; 1988 lhs=alloclhs; 1989 } 1990 if (rhs->digits>reqdigits) { 1991 allocrhs=decRoundOperand(rhs, set, &status); 1992 if (allocrhs==NULL) break; 1993 rhs=allocrhs; 1994 } 1995 } 1996 #endif 1997 /* [following code does not require input rounding] */ 1998 1999 /* handle NaNs and rhs Infinity (lhs infinity is harder) */ 2000 if (SPECIALARGS) { 2001 if (decNumberIsNaN(lhs) || decNumberIsNaN(rhs)) { /* NaNs */ 2002 decNaNs(res, lhs, rhs, set, &status); 2003 break;} 2004 if (decNumberIsInfinite(rhs)) { /* rhs Infinity */ 2005 Flag rhsneg=rhs->bits&DECNEG; /* save rhs sign */ 2006 if (decNumberIsNegative(lhs) /* lhs<0 */ 2007 && !decNumberIsZero(lhs)) /* .. */ 2008 status|=DEC_Invalid_operation; 2009 else { /* lhs >=0 */ 2010 uprv_decNumberZero(&dnOne); /* set up 1 */ 2011 dnOne.lsu[0]=1; 2012 uprv_decNumberCompare(dac, lhs, &dnOne, set); /* lhs ? 1 */ 2013 uprv_decNumberZero(res); /* prepare for 0/1/Infinity */ 2014 if (decNumberIsNegative(dac)) { /* lhs<1 */ 2015 if (rhsneg) res->bits|=DECINF; /* +Infinity [else is +0] */ 2016 } 2017 else if (dac->lsu[0]==0) { /* lhs=1 */ 2018 /* 1**Infinity is inexact, so return fully-padded 1.0000 */ 2019 Int shift=set->digits-1; 2020 *res->lsu=1; /* was 0, make int 1 */ 2021 res->digits=decShiftToMost(res->lsu, 1, shift); 2022 res->exponent=-shift; /* make 1.0000... */ 2023 status|=DEC_Inexact|DEC_Rounded; /* deemed inexact */ 2024 } 2025 else { /* lhs>1 */ 2026 if (!rhsneg) res->bits|=DECINF; /* +Infinity [else is +0] */ 2027 } 2028 } /* lhs>=0 */ 2029 break;} 2030 /* [lhs infinity drops through] */ 2031 } /* specials */ 2032 2033 /* Original rhs may be an integer that fits and is in range */ 2034 n=decGetInt(rhs); 2035 if (n!=BADINT) { /* it is an integer */ 2036 rhsint=1; /* record the fact for 1**n */ 2037 isoddint=(Flag)n&1; /* [works even if big] */ 2038 if (n!=BIGEVEN && n!=BIGODD) /* can use integer path? */ 2039 useint=1; /* looks good */ 2040 } 2041 2042 if (decNumberIsNegative(lhs) /* -x .. */ 2043 && isoddint) bits=DECNEG; /* .. to an odd power */ 2044 2045 /* handle LHS infinity */ 2046 if (decNumberIsInfinite(lhs)) { /* [NaNs already handled] */ 2047 uByte rbits=rhs->bits; /* save */ 2048 uprv_decNumberZero(res); /* prepare */ 2049 if (n==0) *res->lsu=1; /* [-]Inf**0 => 1 */ 2050 else { 2051 /* -Inf**nonint -> error */ 2052 if (!rhsint && decNumberIsNegative(lhs)) { 2053 status|=DEC_Invalid_operation; /* -Inf**nonint is error */ 2054 break;} 2055 if (!(rbits & DECNEG)) bits|=DECINF; /* was not a **-n */ 2056 /* [otherwise will be 0 or -0] */ 2057 res->bits=bits; 2058 } 2059 break;} 2060 2061 /* similarly handle LHS zero */ 2062 if (decNumberIsZero(lhs)) { 2063 if (n==0) { /* 0**0 => Error */ 2064 #if DECSUBSET 2065 if (!set->extended) { /* [unless subset] */ 2066 uprv_decNumberZero(res); 2067 *res->lsu=1; /* return 1 */ 2068 break;} 2069 #endif 2070 status|=DEC_Invalid_operation; 2071 } 2072 else { /* 0**x */ 2073 uByte rbits=rhs->bits; /* save */ 2074 if (rbits & DECNEG) { /* was a 0**(-n) */ 2075 #if DECSUBSET 2076 if (!set->extended) { /* [bad if subset] */ 2077 status|=DEC_Invalid_operation; 2078 break;} 2079 #endif 2080 bits|=DECINF; 2081 } 2082 uprv_decNumberZero(res); /* prepare */ 2083 /* [otherwise will be 0 or -0] */ 2084 res->bits=bits; 2085 } 2086 break;} 2087 2088 /* here both lhs and rhs are finite; rhs==0 is handled in the */ 2089 /* integer path. Next handle the non-integer cases */ 2090 if (!useint) { /* non-integral rhs */ 2091 /* any -ve lhs is bad, as is either operand or context out of */ 2092 /* bounds */ 2093 if (decNumberIsNegative(lhs)) { 2094 status|=DEC_Invalid_operation; 2095 break;} 2096 if (decCheckMath(lhs, set, &status) 2097 || decCheckMath(rhs, set, &status)) break; /* variable status */ 2098 2099 uprv_decContextDefault(&aset, DEC_INIT_DECIMAL64); /* clean context */ 2100 aset.emax=DEC_MAX_MATH; /* usual bounds */ 2101 aset.emin=-DEC_MAX_MATH; /* .. */ 2102 aset.clamp=0; /* and no concrete format */ 2103 2104 /* calculate the result using exp(ln(lhs)*rhs), which can */ 2105 /* all be done into the accumulator, dac. The precision needed */ 2106 /* is enough to contain the full information in the lhs (which */ 2107 /* is the total digits, including exponent), or the requested */ 2108 /* precision, if larger, + 4; 6 is used for the exponent */ 2109 /* maximum length, and this is also used when it is shorter */ 2110 /* than the requested digits as it greatly reduces the >0.5 ulp */ 2111 /* cases at little cost (because Ln doubles digits each */ 2112 /* iteration so a few extra digits rarely causes an extra */ 2113 /* iteration) */ 2114 aset.digits=MAXI(lhs->digits, set->digits)+6+4; 2115 } /* non-integer rhs */ 2116 2117 else { /* rhs is in-range integer */ 2118 if (n==0) { /* x**0 = 1 */ 2119 /* (0**0 was handled above) */ 2120 uprv_decNumberZero(res); /* result=1 */ 2121 *res->lsu=1; /* .. */ 2122 break;} 2123 /* rhs is a non-zero integer */ 2124 if (n<0) n=-n; /* use abs(n) */ 2125 2126 aset=*set; /* clone the context */ 2127 aset.round=DEC_ROUND_HALF_EVEN; /* internally use balanced */ 2128 /* calculate the working DIGITS */ 2129 aset.digits=reqdigits+(rhs->digits+rhs->exponent)+2; 2130 #if DECSUBSET 2131 if (!set->extended) aset.digits--; /* use classic precision */ 2132 #endif 2133 /* it's an error if this is more than can be handled */ 2134 if (aset.digits>DECNUMMAXP) {status|=DEC_Invalid_operation; break;} 2135 } /* integer path */ 2136 2137 /* aset.digits is the count of digits for the accumulator needed */ 2138 /* if accumulator is too long for local storage, then allocate */ 2139 needbytes=sizeof(decNumber)+(D2U(aset.digits)-1)*sizeof(Unit); 2140 /* [needbytes also used below if 1/lhs needed] */ 2141 if (needbytes>sizeof(dacbuff)) { 2142 allocdac=(decNumber *)malloc(needbytes); 2143 if (allocdac==NULL) { /* hopeless -- abandon */ 2144 status|=DEC_Insufficient_storage; 2145 break;} 2146 dac=allocdac; /* use the allocated space */ 2147 } 2148 /* here, aset is set up and accumulator is ready for use */ 2149 2150 if (!useint) { /* non-integral rhs */ 2151 /* x ** y; special-case x=1 here as it will otherwise always */ 2152 /* reduce to integer 1; decLnOp has a fastpath which detects */ 2153 /* the case of x=1 */ 2154 decLnOp(dac, lhs, &aset, &status); /* dac=ln(lhs) */ 2155 /* [no error possible, as lhs 0 already handled] */ 2156 if (ISZERO(dac)) { /* x==1, 1.0, etc. */ 2157 /* need to return fully-padded 1.0000 etc., but rhsint->1 */ 2158 *dac->lsu=1; /* was 0, make int 1 */ 2159 if (!rhsint) { /* add padding */ 2160 Int shift=set->digits-1; 2161 dac->digits=decShiftToMost(dac->lsu, 1, shift); 2162 dac->exponent=-shift; /* make 1.0000... */ 2163 status|=DEC_Inexact|DEC_Rounded; /* deemed inexact */ 2164 } 2165 } 2166 else { 2167 decMultiplyOp(dac, dac, rhs, &aset, &status); /* dac=dac*rhs */ 2168 decExpOp(dac, dac, &aset, &status); /* dac=exp(dac) */ 2169 } 2170 /* and drop through for final rounding */ 2171 } /* non-integer rhs */ 2172 2173 else { /* carry on with integer */ 2174 uprv_decNumberZero(dac); /* acc=1 */ 2175 *dac->lsu=1; /* .. */ 2176 2177 /* if a negative power the constant 1 is needed, and if not subset */ 2178 /* invert the lhs now rather than inverting the result later */ 2179 if (decNumberIsNegative(rhs)) { /* was a **-n [hence digits>0] */ 2180 decNumber *inv=invbuff; /* asssume use fixed buffer */ 2181 uprv_decNumberCopy(&dnOne, dac); /* dnOne=1; [needed now or later] */ 2182 #if DECSUBSET 2183 if (set->extended) { /* need to calculate 1/lhs */ 2184 #endif 2185 /* divide lhs into 1, putting result in dac [dac=1/dac] */ 2186 decDivideOp(dac, &dnOne, lhs, &aset, DIVIDE, &status); 2187 /* now locate or allocate space for the inverted lhs */ 2188 if (needbytes>sizeof(invbuff)) { 2189 allocinv=(decNumber *)malloc(needbytes); 2190 if (allocinv==NULL) { /* hopeless -- abandon */ 2191 status|=DEC_Insufficient_storage; 2192 break;} 2193 inv=allocinv; /* use the allocated space */ 2194 } 2195 /* [inv now points to big-enough buffer or allocated storage] */ 2196 uprv_decNumberCopy(inv, dac); /* copy the 1/lhs */ 2197 uprv_decNumberCopy(dac, &dnOne); /* restore acc=1 */ 2198 lhs=inv; /* .. and go forward with new lhs */ 2199 #if DECSUBSET 2200 } 2201 #endif 2202 } 2203 2204 /* Raise-to-the-power loop... */ 2205 seenbit=0; /* set once a 1-bit is encountered */ 2206 for (i=1;;i++){ /* for each bit [top bit ignored] */ 2207 /* abandon if had overflow or terminal underflow */ 2208 if (status & (DEC_Overflow|DEC_Underflow)) { /* interesting? */ 2209 if (status&DEC_Overflow || ISZERO(dac)) break; 2210 } 2211 /* [the following two lines revealed an optimizer bug in a C++ */ 2212 /* compiler, with symptom: 5**3 -> 25, when n=n+n was used] */ 2213 n=n<<1; /* move next bit to testable position */ 2214 if (n<0) { /* top bit is set */ 2215 seenbit=1; /* OK, significant bit seen */ 2216 decMultiplyOp(dac, dac, lhs, &aset, &status); /* dac=dac*x */ 2217 } 2218 if (i==31) break; /* that was the last bit */ 2219 if (!seenbit) continue; /* no need to square 1 */ 2220 decMultiplyOp(dac, dac, dac, &aset, &status); /* dac=dac*dac [square] */ 2221 } /*i*/ /* 32 bits */ 2222 2223 /* complete internal overflow or underflow processing */ 2224 if (status & (DEC_Overflow|DEC_Underflow)) { 2225 #if DECSUBSET 2226 /* If subset, and power was negative, reverse the kind of -erflow */ 2227 /* [1/x not yet done] */ 2228 if (!set->extended && decNumberIsNegative(rhs)) { 2229 if (status & DEC_Overflow) 2230 status^=DEC_Overflow | DEC_Underflow | DEC_Subnormal; 2231 else { /* trickier -- Underflow may or may not be set */ 2232 status&=~(DEC_Underflow | DEC_Subnormal); /* [one or both] */ 2233 status|=DEC_Overflow; 2234 } 2235 } 2236 #endif 2237 dac->bits=(dac->bits & ~DECNEG) | bits; /* force correct sign */ 2238 /* round subnormals [to set.digits rather than aset.digits] */ 2239 /* or set overflow result similarly as required */ 2240 decFinalize(dac, set, &residue, &status); 2241 uprv_decNumberCopy(res, dac); /* copy to result (is now OK length) */ 2242 break; 2243 } 2244 2245 #if DECSUBSET 2246 if (!set->extended && /* subset math */ 2247 decNumberIsNegative(rhs)) { /* was a **-n [hence digits>0] */ 2248 /* so divide result into 1 [dac=1/dac] */ 2249 decDivideOp(dac, &dnOne, dac, &aset, DIVIDE, &status); 2250 } 2251 #endif 2252 } /* rhs integer path */ 2253 2254 /* reduce result to the requested length and copy to result */ 2255 decCopyFit(res, dac, set, &residue, &status); 2256 decFinish(res, set, &residue, &status); /* final cleanup */ 2257 #if DECSUBSET 2258 if (!set->extended) decTrim(res, set, 0, 1, &dropped); /* trailing zeros */ 2259 #endif 2260 } while(0); /* end protected */ 2261 2262 if (allocdac!=NULL) free(allocdac); /* drop any storage used */ 2263 if (allocinv!=NULL) free(allocinv); /* .. */ 2264 #if DECSUBSET 2265 if (alloclhs!=NULL) free(alloclhs); /* .. */ 2266 if (allocrhs!=NULL) free(allocrhs); /* .. */ 2267 #endif 2268 if (status!=0) decStatus(res, status, set); 2269 #if DECCHECK 2270 decCheckInexact(res, set); 2271 #endif 2272 return res; 2273 } /* decNumberPower */ 2274 2275 /* ------------------------------------------------------------------ */ 2276 /* decNumberQuantize -- force exponent to requested value */ 2277 /* */ 2278 /* This computes C = op(A, B), where op adjusts the coefficient */ 2279 /* of C (by rounding or shifting) such that the exponent (-scale) */ 2280 /* of C has exponent of B. The numerical value of C will equal A, */ 2281 /* except for the effects of any rounding that occurred. */ 2282 /* */ 2283 /* res is C, the result. C may be A or B */ 2284 /* lhs is A, the number to adjust */ 2285 /* rhs is B, the number with exponent to match */ 2286 /* set is the context */ 2287 /* */ 2288 /* C must have space for set->digits digits. */ 2289 /* */ 2290 /* Unless there is an error or the result is infinite, the exponent */ 2291 /* after the operation is guaranteed to be equal to that of B. */ 2292 /* ------------------------------------------------------------------ */ 2293 U_CAPI decNumber * U_EXPORT2 uprv_decNumberQuantize(decNumber *res, const decNumber *lhs, 2294 const decNumber *rhs, decContext *set) { 2295 uInt status=0; /* accumulator */ 2296 decQuantizeOp(res, lhs, rhs, set, 1, &status); 2297 if (status!=0) decStatus(res, status, set); 2298 return res; 2299 } /* decNumberQuantize */ 2300 2301 /* ------------------------------------------------------------------ */ 2302 /* decNumberReduce -- remove trailing zeros */ 2303 /* */ 2304 /* This computes C = 0 + A, and normalizes the result */ 2305 /* */ 2306 /* res is C, the result. C may be A */ 2307 /* rhs is A */ 2308 /* set is the context */ 2309 /* */ 2310 /* C must have space for set->digits digits. */ 2311 /* ------------------------------------------------------------------ */ 2312 /* Previously known as Normalize */ 2313 U_CAPI decNumber * U_EXPORT2 uprv_decNumberNormalize(decNumber *res, const decNumber *rhs, 2314 decContext *set) { 2315 return uprv_decNumberReduce(res, rhs, set); 2316 } /* decNumberNormalize */ 2317 2318 U_CAPI decNumber * U_EXPORT2 uprv_decNumberReduce(decNumber *res, const decNumber *rhs, 2319 decContext *set) { 2320 #if DECSUBSET 2321 decNumber *allocrhs=NULL; /* non-NULL if rounded rhs allocated */ 2322 #endif 2323 uInt status=0; /* as usual */ 2324 Int residue=0; /* as usual */ 2325 Int dropped; /* work */ 2326 2327 #if DECCHECK 2328 if (decCheckOperands(res, DECUNUSED, rhs, set)) return res; 2329 #endif 2330 2331 do { /* protect allocated storage */ 2332 #if DECSUBSET 2333 if (!set->extended) { 2334 /* reduce operand and set lostDigits status, as needed */ 2335 if (rhs->digits>set->digits) { 2336 allocrhs=decRoundOperand(rhs, set, &status); 2337 if (allocrhs==NULL) break; 2338 rhs=allocrhs; 2339 } 2340 } 2341 #endif 2342 /* [following code does not require input rounding] */ 2343 2344 /* Infinities copy through; NaNs need usual treatment */ 2345 if (decNumberIsNaN(rhs)) { 2346 decNaNs(res, rhs, NULL, set, &status); 2347 break; 2348 } 2349 2350 /* reduce result to the requested length and copy to result */ 2351 decCopyFit(res, rhs, set, &residue, &status); /* copy & round */ 2352 decFinish(res, set, &residue, &status); /* cleanup/set flags */ 2353 decTrim(res, set, 1, 0, &dropped); /* normalize in place */ 2354 /* [may clamp] */ 2355 } while(0); /* end protected */ 2356 2357 #if DECSUBSET 2358 if (allocrhs !=NULL) free(allocrhs); /* .. */ 2359 #endif 2360 if (status!=0) decStatus(res, status, set);/* then report status */ 2361 return res; 2362 } /* decNumberReduce */ 2363 2364 /* ------------------------------------------------------------------ */ 2365 /* decNumberRescale -- force exponent to requested value */ 2366 /* */ 2367 /* This computes C = op(A, B), where op adjusts the coefficient */ 2368 /* of C (by rounding or shifting) such that the exponent (-scale) */ 2369 /* of C has the value B. The numerical value of C will equal A, */ 2370 /* except for the effects of any rounding that occurred. */ 2371 /* */ 2372 /* res is C, the result. C may be A or B */ 2373 /* lhs is A, the number to adjust */ 2374 /* rhs is B, the requested exponent */ 2375 /* set is the context */ 2376 /* */ 2377 /* C must have space for set->digits digits. */ 2378 /* */ 2379 /* Unless there is an error or the result is infinite, the exponent */ 2380 /* after the operation is guaranteed to be equal to B. */ 2381 /* ------------------------------------------------------------------ */ 2382 U_CAPI decNumber * U_EXPORT2 uprv_decNumberRescale(decNumber *res, const decNumber *lhs, 2383 const decNumber *rhs, decContext *set) { 2384 uInt status=0; /* accumulator */ 2385 decQuantizeOp(res, lhs, rhs, set, 0, &status); 2386 if (status!=0) decStatus(res, status, set); 2387 return res; 2388 } /* decNumberRescale */ 2389 2390 /* ------------------------------------------------------------------ */ 2391 /* decNumberRemainder -- divide and return remainder */ 2392 /* */ 2393 /* This computes C = A % B */ 2394 /* */ 2395 /* res is C, the result. C may be A and/or B (e.g., X=X%X) */ 2396 /* lhs is A */ 2397 /* rhs is B */ 2398 /* set is the context */ 2399 /* */ 2400 /* C must have space for set->digits digits. */ 2401 /* ------------------------------------------------------------------ */ 2402 U_CAPI decNumber * U_EXPORT2 uprv_decNumberRemainder(decNumber *res, const decNumber *lhs, 2403 const decNumber *rhs, decContext *set) { 2404 uInt status=0; /* accumulator */ 2405 decDivideOp(res, lhs, rhs, set, REMAINDER, &status); 2406 if (status!=0) decStatus(res, status, set); 2407 #if DECCHECK 2408 decCheckInexact(res, set); 2409 #endif 2410 return res; 2411 } /* decNumberRemainder */ 2412 2413 /* ------------------------------------------------------------------ */ 2414 /* decNumberRemainderNear -- divide and return remainder from nearest */ 2415 /* */ 2416 /* This computes C = A % B, where % is the IEEE remainder operator */ 2417 /* */ 2418 /* res is C, the result. C may be A and/or B (e.g., X=X%X) */ 2419 /* lhs is A */ 2420 /* rhs is B */ 2421 /* set is the context */ 2422 /* */ 2423 /* C must have space for set->digits digits. */ 2424 /* ------------------------------------------------------------------ */ 2425 U_CAPI decNumber * U_EXPORT2 uprv_decNumberRemainderNear(decNumber *res, const decNumber *lhs, 2426 const decNumber *rhs, decContext *set) { 2427 uInt status=0; /* accumulator */ 2428 decDivideOp(res, lhs, rhs, set, REMNEAR, &status); 2429 if (status!=0) decStatus(res, status, set); 2430 #if DECCHECK 2431 decCheckInexact(res, set); 2432 #endif 2433 return res; 2434 } /* decNumberRemainderNear */ 2435 2436 /* ------------------------------------------------------------------ */ 2437 /* decNumberRotate -- rotate the coefficient of a Number left/right */ 2438 /* */ 2439 /* This computes C = A rot B (in base ten and rotating set->digits */ 2440 /* digits). */ 2441 /* */ 2442 /* res is C, the result. C may be A and/or B (e.g., X=XrotX) */ 2443 /* lhs is A */ 2444 /* rhs is B, the number of digits to rotate (-ve to right) */ 2445 /* set is the context */ 2446 /* */ 2447 /* The digits of the coefficient of A are rotated to the left (if B */ 2448 /* is positive) or to the right (if B is negative) without adjusting */ 2449 /* the exponent or the sign of A. If lhs->digits is less than */ 2450 /* set->digits the coefficient is padded with zeros on the left */ 2451 /* before the rotate. Any leading zeros in the result are removed */ 2452 /* as usual. */ 2453 /* */ 2454 /* B must be an integer (q=0) and in the range -set->digits through */ 2455 /* +set->digits. */ 2456 /* C must have space for set->digits digits. */ 2457 /* NaNs are propagated as usual. Infinities are unaffected (but */ 2458 /* B must be valid). No status is set unless B is invalid or an */ 2459 /* operand is an sNaN. */ 2460 /* ------------------------------------------------------------------ */ 2461 U_CAPI decNumber * U_EXPORT2 uprv_decNumberRotate(decNumber *res, const decNumber *lhs, 2462 const decNumber *rhs, decContext *set) { 2463 uInt status=0; /* accumulator */ 2464 Int rotate; /* rhs as an Int */ 2465 2466 #if DECCHECK 2467 if (decCheckOperands(res, lhs, rhs, set)) return res; 2468 #endif 2469 2470 /* NaNs propagate as normal */ 2471 if (decNumberIsNaN(lhs) || decNumberIsNaN(rhs)) 2472 decNaNs(res, lhs, rhs, set, &status); 2473 /* rhs must be an integer */ 2474 else if (decNumberIsInfinite(rhs) || rhs->exponent!=0) 2475 status=DEC_Invalid_operation; 2476 else { /* both numeric, rhs is an integer */ 2477 rotate=decGetInt(rhs); /* [cannot fail] */ 2478 if (rotate==BADINT /* something bad .. */ 2479 || rotate==BIGODD || rotate==BIGEVEN /* .. very big .. */ 2480 || abs(rotate)>set->digits) /* .. or out of range */ 2481 status=DEC_Invalid_operation; 2482 else { /* rhs is OK */ 2483 uprv_decNumberCopy(res, lhs); 2484 /* convert -ve rotate to equivalent positive rotation */ 2485 if (rotate<0) rotate=set->digits+rotate; 2486 if (rotate!=0 && rotate!=set->digits /* zero or full rotation */ 2487 && !decNumberIsInfinite(res)) { /* lhs was infinite */ 2488 /* left-rotate to do; 0 < rotate < set->digits */ 2489 uInt units, shift; /* work */ 2490 uInt msudigits; /* digits in result msu */ 2491 Unit *msu=res->lsu+D2U(res->digits)-1; /* current msu */ 2492 Unit *msumax=res->lsu+D2U(set->digits)-1; /* rotation msu */ 2493 for (msu++; msu<=msumax; msu++) *msu=0; /* ensure high units=0 */ 2494 res->digits=set->digits; /* now full-length */ 2495 msudigits=MSUDIGITS(res->digits); /* actual digits in msu */ 2496 2497 /* rotation here is done in-place, in three steps */ 2498 /* 1. shift all to least up to one unit to unit-align final */ 2499 /* lsd [any digits shifted out are rotated to the left, */ 2500 /* abutted to the original msd (which may require split)] */ 2501 /* */ 2502 /* [if there are no whole units left to rotate, the */ 2503 /* rotation is now complete] */ 2504 /* */ 2505 /* 2. shift to least, from below the split point only, so that */ 2506 /* the final msd is in the right place in its Unit [any */ 2507 /* digits shifted out will fit exactly in the current msu, */ 2508 /* left aligned, no split required] */ 2509 /* */ 2510 /* 3. rotate all the units by reversing left part, right */ 2511 /* part, and then whole */ 2512 /* */ 2513 /* example: rotate right 8 digits (2 units + 2), DECDPUN=3. */ 2514 /* */ 2515 /* start: 00a bcd efg hij klm npq */ 2516 /* */ 2517 /* 1a 000 0ab cde fgh|ijk lmn [pq saved] */ 2518 /* 1b 00p qab cde fgh|ijk lmn */ 2519 /* */ 2520 /* 2a 00p qab cde fgh|00i jkl [mn saved] */ 2521 /* 2b mnp qab cde fgh|00i jkl */ 2522 /* */ 2523 /* 3a fgh cde qab mnp|00i jkl */ 2524 /* 3b fgh cde qab mnp|jkl 00i */ 2525 /* 3c 00i jkl mnp qab cde fgh */ 2526 2527 /* Step 1: amount to shift is the partial right-rotate count */ 2528 rotate=set->digits-rotate; /* make it right-rotate */ 2529 units=rotate/DECDPUN; /* whole units to rotate */ 2530 shift=rotate%DECDPUN; /* left-over digits count */ 2531 if (shift>0) { /* not an exact number of units */ 2532 uInt save=res->lsu[0]%powers[shift]; /* save low digit(s) */ 2533 decShiftToLeast(res->lsu, D2U(res->digits), shift); 2534 if (shift>msudigits) { /* msumax-1 needs >0 digits */ 2535 uInt rem=save%powers[shift-msudigits];/* split save */ 2536 *msumax=(Unit)(save/powers[shift-msudigits]); /* and insert */ 2537 *(msumax-1)=*(msumax-1) 2538 +(Unit)(rem*powers[DECDPUN-(shift-msudigits)]); /* .. */ 2539 } 2540 else { /* all fits in msumax */ 2541 *msumax=*msumax+(Unit)(save*powers[msudigits-shift]); /* [maybe *1] */ 2542 } 2543 } /* digits shift needed */ 2544 2545 /* If whole units to rotate... */ 2546 if (units>0) { /* some to do */ 2547 /* Step 2: the units to touch are the whole ones in rotate, */ 2548 /* if any, and the shift is DECDPUN-msudigits (which may be */ 2549 /* 0, again) */ 2550 shift=DECDPUN-msudigits; 2551 if (shift>0) { /* not an exact number of units */ 2552 uInt save=res->lsu[0]%powers[shift]; /* save low digit(s) */ 2553 decShiftToLeast(res->lsu, units, shift); 2554 *msumax=*msumax+(Unit)(save*powers[msudigits]); 2555 } /* partial shift needed */ 2556 2557 /* Step 3: rotate the units array using triple reverse */ 2558 /* (reversing is easy and fast) */ 2559 decReverse(res->lsu+units, msumax); /* left part */ 2560 decReverse(res->lsu, res->lsu+units-1); /* right part */ 2561 decReverse(res->lsu, msumax); /* whole */ 2562 } /* whole units to rotate */ 2563 /* the rotation may have left an undetermined number of zeros */ 2564 /* on the left, so true length needs to be calculated */ 2565 res->digits=decGetDigits(res->lsu, msumax-res->lsu+1); 2566 } /* rotate needed */ 2567 } /* rhs OK */ 2568 } /* numerics */ 2569 if (status!=0) decStatus(res, status, set); 2570 return res; 2571 } /* decNumberRotate */ 2572 2573 /* ------------------------------------------------------------------ */ 2574 /* decNumberSameQuantum -- test for equal exponents */ 2575 /* */ 2576 /* res is the result number, which will contain either 0 or 1 */ 2577 /* lhs is a number to test */ 2578 /* rhs is the second (usually a pattern) */ 2579 /* */ 2580 /* No errors are possible and no context is needed. */ 2581 /* ------------------------------------------------------------------ */ 2582 U_CAPI decNumber * U_EXPORT2 uprv_decNumberSameQuantum(decNumber *res, const decNumber *lhs, 2583 const decNumber *rhs) { 2584 Unit ret=0; /* return value */ 2585 2586 #if DECCHECK 2587 if (decCheckOperands(res, lhs, rhs, DECUNCONT)) return res; 2588 #endif 2589 2590 if (SPECIALARGS) { 2591 if (decNumberIsNaN(lhs) && decNumberIsNaN(rhs)) ret=1; 2592 else if (decNumberIsInfinite(lhs) && decNumberIsInfinite(rhs)) ret=1; 2593 /* [anything else with a special gives 0] */ 2594 } 2595 else if (lhs->exponent==rhs->exponent) ret=1; 2596 2597 uprv_decNumberZero(res); /* OK to overwrite an operand now */ 2598 *res->lsu=ret; 2599 return res; 2600 } /* decNumberSameQuantum */ 2601 2602 /* ------------------------------------------------------------------ */ 2603 /* decNumberScaleB -- multiply by a power of 10 */ 2604 /* */ 2605 /* This computes C = A x 10**B where B is an integer (q=0) with */ 2606 /* maximum magnitude 2*(emax+digits) */ 2607 /* */ 2608 /* res is C, the result. C may be A or B */ 2609 /* lhs is A, the number to adjust */ 2610 /* rhs is B, the requested power of ten to use */ 2611 /* set is the context */ 2612 /* */ 2613 /* C must have space for set->digits digits. */ 2614 /* */ 2615 /* The result may underflow or overflow. */ 2616 /* ------------------------------------------------------------------ */ 2617 U_CAPI decNumber * U_EXPORT2 uprv_decNumberScaleB(decNumber *res, const decNumber *lhs, 2618 const decNumber *rhs, decContext *set) { 2619 Int reqexp; /* requested exponent change [B] */ 2620 uInt status=0; /* accumulator */ 2621 Int residue; /* work */ 2622 2623 #if DECCHECK 2624 if (decCheckOperands(res, lhs, rhs, set)) return res; 2625 #endif 2626 2627 /* Handle special values except lhs infinite */ 2628 if (decNumberIsNaN(lhs) || decNumberIsNaN(rhs)) 2629 decNaNs(res, lhs, rhs, set, &status); 2630 /* rhs must be an integer */ 2631 else if (decNumberIsInfinite(rhs) || rhs->exponent!=0) 2632 status=DEC_Invalid_operation; 2633 else { 2634 /* lhs is a number; rhs is a finite with q==0 */ 2635 reqexp=decGetInt(rhs); /* [cannot fail] */ 2636 if (reqexp==BADINT /* something bad .. */ 2637 || reqexp==BIGODD || reqexp==BIGEVEN /* .. very big .. */ 2638 || abs(reqexp)>(2*(set->digits+set->emax))) /* .. or out of range */ 2639 status=DEC_Invalid_operation; 2640 else { /* rhs is OK */ 2641 uprv_decNumberCopy(res, lhs); /* all done if infinite lhs */ 2642 if (!decNumberIsInfinite(res)) { /* prepare to scale */ 2643 res->exponent+=reqexp; /* adjust the exponent */ 2644 residue=0; 2645 decFinalize(res, set, &residue, &status); /* .. and check */ 2646 } /* finite LHS */ 2647 } /* rhs OK */ 2648 } /* rhs finite */ 2649 if (status!=0) decStatus(res, status, set); 2650 return res; 2651 } /* decNumberScaleB */ 2652 2653 /* ------------------------------------------------------------------ */ 2654 /* decNumberShift -- shift the coefficient of a Number left or right */ 2655 /* */ 2656 /* This computes C = A << B or C = A >> -B (in base ten). */ 2657 /* */ 2658 /* res is C, the result. C may be A and/or B (e.g., X=X<<X) */ 2659 /* lhs is A */ 2660 /* rhs is B, the number of digits to shift (-ve to right) */ 2661 /* set is the context */ 2662 /* */ 2663 /* The digits of the coefficient of A are shifted to the left (if B */ 2664 /* is positive) or to the right (if B is negative) without adjusting */ 2665 /* the exponent or the sign of A. */ 2666 /* */ 2667 /* B must be an integer (q=0) and in the range -set->digits through */ 2668 /* +set->digits. */ 2669 /* C must have space for set->digits digits. */ 2670 /* NaNs are propagated as usual. Infinities are unaffected (but */ 2671 /* B must be valid). No status is set unless B is invalid or an */ 2672 /* operand is an sNaN. */ 2673 /* ------------------------------------------------------------------ */ 2674 U_CAPI decNumber * U_EXPORT2 uprv_decNumberShift(decNumber *res, const decNumber *lhs, 2675 const decNumber *rhs, decContext *set) { 2676 uInt status=0; /* accumulator */ 2677 Int shift; /* rhs as an Int */ 2678 2679 #if DECCHECK 2680 if (decCheckOperands(res, lhs, rhs, set)) return res; 2681 #endif 2682 2683 /* NaNs propagate as normal */ 2684 if (decNumberIsNaN(lhs) || decNumberIsNaN(rhs)) 2685 decNaNs(res, lhs, rhs, set, &status); 2686 /* rhs must be an integer */ 2687 else if (decNumberIsInfinite(rhs) || rhs->exponent!=0) 2688 status=DEC_Invalid_operation; 2689 else { /* both numeric, rhs is an integer */ 2690 shift=decGetInt(rhs); /* [cannot fail] */ 2691 if (shift==BADINT /* something bad .. */ 2692 || shift==BIGODD || shift==BIGEVEN /* .. very big .. */ 2693 || abs(shift)>set->digits) /* .. or out of range */ 2694 status=DEC_Invalid_operation; 2695 else { /* rhs is OK */ 2696 uprv_decNumberCopy(res, lhs); 2697 if (shift!=0 && !decNumberIsInfinite(res)) { /* something to do */ 2698 if (shift>0) { /* to left */ 2699 if (shift==set->digits) { /* removing all */ 2700 *res->lsu=0; /* so place 0 */ 2701 res->digits=1; /* .. */ 2702 } 2703 else { /* */ 2704 /* first remove leading digits if necessary */ 2705 if (res->digits+shift>set->digits) { 2706 decDecap(res, res->digits+shift-set->digits); 2707 /* that updated res->digits; may have gone to 1 (for a */ 2708 /* single digit or for zero */ 2709 } 2710 if (res->digits>1 || *res->lsu) /* if non-zero.. */ 2711 res->digits=decShiftToMost(res->lsu, res->digits, shift); 2712 } /* partial left */ 2713 } /* left */ 2714 else { /* to right */ 2715 if (-shift>=res->digits) { /* discarding all */ 2716 *res->lsu=0; /* so place 0 */ 2717 res->digits=1; /* .. */ 2718 } 2719 else { 2720 decShiftToLeast(res->lsu, D2U(res->digits), -shift); 2721 res->digits-=(-shift); 2722 } 2723 } /* to right */ 2724 } /* non-0 non-Inf shift */ 2725 } /* rhs OK */ 2726 } /* numerics */ 2727 if (status!=0) decStatus(res, status, set); 2728 return res; 2729 } /* decNumberShift */ 2730 2731 /* ------------------------------------------------------------------ */ 2732 /* decNumberSquareRoot -- square root operator */ 2733 /* */ 2734 /* This computes C = squareroot(A) */ 2735 /* */ 2736 /* res is C, the result. C may be A */ 2737 /* rhs is A */ 2738 /* set is the context; note that rounding mode has no effect */ 2739 /* */ 2740 /* C must have space for set->digits digits. */ 2741 /* ------------------------------------------------------------------ */ 2742 /* This uses the following varying-precision algorithm in: */ 2743 /* */ 2744 /* Properly Rounded Variable Precision Square Root, T. E. Hull and */ 2745 /* A. Abrham, ACM Transactions on Mathematical Software, Vol 11 #3, */ 2746 /* pp229-237, ACM, September 1985. */ 2747 /* */ 2748 /* The square-root is calculated using Newton's method, after which */ 2749 /* a check is made to ensure the result is correctly rounded. */ 2750 /* */ 2751 /* % [Reformatted original Numerical Turing source code follows.] */ 2752 /* function sqrt(x : real) : real */ 2753 /* % sqrt(x) returns the properly rounded approximation to the square */ 2754 /* % root of x, in the precision of the calling environment, or it */ 2755 /* % fails if x < 0. */ 2756 /* % t e hull and a abrham, august, 1984 */ 2757 /* if x <= 0 then */ 2758 /* if x < 0 then */ 2759 /* assert false */ 2760 /* else */ 2761 /* result 0 */ 2762 /* end if */ 2763 /* end if */ 2764 /* var f := setexp(x, 0) % fraction part of x [0.1 <= x < 1] */ 2765 /* var e := getexp(x) % exponent part of x */ 2766 /* var approx : real */ 2767 /* if e mod 2 = 0 then */ 2768 /* approx := .259 + .819 * f % approx to root of f */ 2769 /* else */ 2770 /* f := f/l0 % adjustments */ 2771 /* e := e + 1 % for odd */ 2772 /* approx := .0819 + 2.59 * f % exponent */ 2773 /* end if */ 2774 /* */ 2775 /* var p:= 3 */ 2776 /* const maxp := currentprecision + 2 */ 2777 /* loop */ 2778 /* p := min(2*p - 2, maxp) % p = 4,6,10, . . . , maxp */ 2779 /* precision p */ 2780 /* approx := .5 * (approx + f/approx) */ 2781 /* exit when p = maxp */ 2782 /* end loop */ 2783 /* */ 2784 /* % approx is now within 1 ulp of the properly rounded square root */ 2785 /* % of f; to ensure proper rounding, compare squares of (approx - */ 2786 /* % l/2 ulp) and (approx + l/2 ulp) with f. */ 2787 /* p := currentprecision */ 2788 /* begin */ 2789 /* precision p + 2 */ 2790 /* const approxsubhalf := approx - setexp(.5, -p) */ 2791 /* if mulru(approxsubhalf, approxsubhalf) > f then */ 2792 /* approx := approx - setexp(.l, -p + 1) */ 2793 /* else */ 2794 /* const approxaddhalf := approx + setexp(.5, -p) */ 2795 /* if mulrd(approxaddhalf, approxaddhalf) < f then */ 2796 /* approx := approx + setexp(.l, -p + 1) */ 2797 /* end if */ 2798 /* end if */ 2799 /* end */ 2800 /* result setexp(approx, e div 2) % fix exponent */ 2801 /* end sqrt */ 2802 /* ------------------------------------------------------------------ */ 2803 U_CAPI decNumber * U_EXPORT2 uprv_decNumberSquareRoot(decNumber *res, const decNumber *rhs, 2804 decContext *set) { 2805 decContext workset, approxset; /* work contexts */ 2806 decNumber dzero; /* used for constant zero */ 2807 Int maxp; /* largest working precision */ 2808 Int workp; /* working precision */ 2809 Int residue=0; /* rounding residue */ 2810 uInt status=0, ignore=0; /* status accumulators */ 2811 uInt rstatus; /* .. */ 2812 Int exp; /* working exponent */ 2813 Int ideal; /* ideal (preferred) exponent */ 2814 Int needbytes; /* work */ 2815 Int dropped; /* .. */ 2816 2817 #if DECSUBSET 2818 decNumber *allocrhs=NULL; /* non-NULL if rounded rhs allocated */ 2819 #endif 2820 /* buffer for f [needs +1 in case DECBUFFER 0] */ 2821 decNumber buff[D2N(DECBUFFER+1)]; 2822 /* buffer for a [needs +2 to match likely maxp] */ 2823 decNumber bufa[D2N(DECBUFFER+2)]; 2824 /* buffer for temporary, b [must be same size as a] */ 2825 decNumber bufb[D2N(DECBUFFER+2)]; 2826 decNumber *allocbuff=NULL; /* -> allocated buff, iff allocated */ 2827 decNumber *allocbufa=NULL; /* -> allocated bufa, iff allocated */ 2828 decNumber *allocbufb=NULL; /* -> allocated bufb, iff allocated */ 2829 decNumber *f=buff; /* reduced fraction */ 2830 decNumber *a=bufa; /* approximation to result */ 2831 decNumber *b=bufb; /* intermediate result */ 2832 /* buffer for temporary variable, up to 3 digits */ 2833 decNumber buft[D2N(3)]; 2834 decNumber *t=buft; /* up-to-3-digit constant or work */ 2835 2836 #if DECCHECK 2837 if (decCheckOperands(res, DECUNUSED, rhs, set)) return res; 2838 #endif 2839 2840 do { /* protect allocated storage */ 2841 #if DECSUBSET 2842 if (!set->extended) { 2843 /* reduce operand and set lostDigits status, as needed */ 2844 if (rhs->digits>set->digits) { 2845 allocrhs=decRoundOperand(rhs, set, &status); 2846 if (allocrhs==NULL) break; 2847 /* [Note: 'f' allocation below could reuse this buffer if */ 2848 /* used, but as this is rare they are kept separate for clarity.] */ 2849 rhs=allocrhs; 2850 } 2851 } 2852 #endif 2853 /* [following code does not require input rounding] */ 2854 2855 /* handle infinities and NaNs */ 2856 if (SPECIALARG) { 2857 if (decNumberIsInfinite(rhs)) { /* an infinity */ 2858 if (decNumberIsNegative(rhs)) status|=DEC_Invalid_operation; 2859 else uprv_decNumberCopy(res, rhs); /* +Infinity */ 2860 } 2861 else decNaNs(res, rhs, NULL, set, &status); /* a NaN */ 2862 break; 2863 } 2864 2865 /* calculate the ideal (preferred) exponent [floor(exp/2)] */ 2866 /* [It would be nicer to write: ideal=rhs->exponent>>1, but this */ 2867 /* generates a compiler warning. Generated code is the same.] */ 2868 ideal=(rhs->exponent&~1)/2; /* target */ 2869 2870 /* handle zeros */ 2871 if (ISZERO(rhs)) { 2872 uprv_decNumberCopy(res, rhs); /* could be 0 or -0 */ 2873 res->exponent=ideal; /* use the ideal [safe] */ 2874 /* use decFinish to clamp any out-of-range exponent, etc. */ 2875 decFinish(res, set, &residue, &status); 2876 break; 2877 } 2878 2879 /* any other -x is an oops */ 2880 if (decNumberIsNegative(rhs)) { 2881 status|=DEC_Invalid_operation; 2882 break; 2883 } 2884 2885 /* space is needed for three working variables */ 2886 /* f -- the same precision as the RHS, reduced to 0.01->0.99... */ 2887 /* a -- Hull's approximation -- precision, when assigned, is */ 2888 /* currentprecision+1 or the input argument precision, */ 2889 /* whichever is larger (+2 for use as temporary) */ 2890 /* b -- intermediate temporary result (same size as a) */ 2891 /* if any is too long for local storage, then allocate */ 2892 workp=MAXI(set->digits+1, rhs->digits); /* actual rounding precision */ 2893 workp=MAXI(workp, 7); /* at least 7 for low cases */ 2894 maxp=workp+2; /* largest working precision */ 2895 2896 needbytes=sizeof(decNumber)+(D2U(rhs->digits)-1)*sizeof(Unit); 2897 if (needbytes>(Int)sizeof(buff)) { 2898 allocbuff=(decNumber *)malloc(needbytes); 2899 if (allocbuff==NULL) { /* hopeless -- abandon */ 2900 status|=DEC_Insufficient_storage; 2901 break;} 2902 f=allocbuff; /* use the allocated space */ 2903 } 2904 /* a and b both need to be able to hold a maxp-length number */ 2905 needbytes=sizeof(decNumber)+(D2U(maxp)-1)*sizeof(Unit); 2906 if (needbytes>(Int)sizeof(bufa)) { /* [same applies to b] */ 2907 allocbufa=(decNumber *)malloc(needbytes); 2908 allocbufb=(decNumber *)malloc(needbytes); 2909 if (allocbufa==NULL || allocbufb==NULL) { /* hopeless */ 2910 status|=DEC_Insufficient_storage; 2911 break;} 2912 a=allocbufa; /* use the allocated spaces */ 2913 b=allocbufb; /* .. */ 2914 } 2915 2916 /* copy rhs -> f, save exponent, and reduce so 0.1 <= f < 1 */ 2917 uprv_decNumberCopy(f, rhs); 2918 exp=f->exponent+f->digits; /* adjusted to Hull rules */ 2919 f->exponent=-(f->digits); /* to range */ 2920 2921 /* set up working context */ 2922 uprv_decContextDefault(&workset, DEC_INIT_DECIMAL64); 2923 workset.emax=DEC_MAX_EMAX; 2924 workset.emin=DEC_MIN_EMIN; 2925 2926 /* [Until further notice, no error is possible and status bits */ 2927 /* (Rounded, etc.) should be ignored, not accumulated.] */ 2928 2929 /* Calculate initial approximation, and allow for odd exponent */ 2930 workset.digits=workp; /* p for initial calculation */ 2931 t->bits=0; t->digits=3; 2932 a->bits=0; a->digits=3; 2933 if ((exp & 1)==0) { /* even exponent */ 2934 /* Set t=0.259, a=0.819 */ 2935 t->exponent=-3; 2936 a->exponent=-3; 2937 #if DECDPUN>=3 2938 t->lsu[0]=259; 2939 a->lsu[0]=819; 2940 #elif DECDPUN==2 2941 t->lsu[0]=59; t->lsu[1]=2; 2942 a->lsu[0]=19; a->lsu[1]=8; 2943 #else 2944 t->lsu[0]=9; t->lsu[1]=5; t->lsu[2]=2; 2945 a->lsu[0]=9; a->lsu[1]=1; a->lsu[2]=8; 2946 #endif 2947 } 2948 else { /* odd exponent */ 2949 /* Set t=0.0819, a=2.59 */ 2950 f->exponent--; /* f=f/10 */ 2951 exp++; /* e=e+1 */ 2952 t->exponent=-4; 2953 a->exponent=-2; 2954 #if DECDPUN>=3 2955 t->lsu[0]=819; 2956 a->lsu[0]=259; 2957 #elif DECDPUN==2 2958 t->lsu[0]=19; t->lsu[1]=8; 2959 a->lsu[0]=59; a->lsu[1]=2; 2960 #else 2961 t->lsu[0]=9; t->lsu[1]=1; t->lsu[2]=8; 2962 a->lsu[0]=9; a->lsu[1]=5; a->lsu[2]=2; 2963 #endif 2964 } 2965 2966 decMultiplyOp(a, a, f, &workset, &ignore); /* a=a*f */ 2967 decAddOp(a, a, t, &workset, 0, &ignore); /* ..+t */ 2968 /* [a is now the initial approximation for sqrt(f), calculated with */ 2969 /* currentprecision, which is also a's precision.] */ 2970 2971 /* the main calculation loop */ 2972 uprv_decNumberZero(&dzero); /* make 0 */ 2973 uprv_decNumberZero(t); /* set t = 0.5 */ 2974 t->lsu[0]=5; /* .. */ 2975 t->exponent=-1; /* .. */ 2976 workset.digits=3; /* initial p */ 2977 for (; workset.digits<maxp;) { 2978 /* set p to min(2*p - 2, maxp) [hence 3; or: 4, 6, 10, ... , maxp] */ 2979 workset.digits=MINI(workset.digits*2-2, maxp); 2980 /* a = 0.5 * (a + f/a) */ 2981 /* [calculated at p then rounded to currentprecision] */ 2982 decDivideOp(b, f, a, &workset, DIVIDE, &ignore); /* b=f/a */ 2983 decAddOp(b, b, a, &workset, 0, &ignore); /* b=b+a */ 2984 decMultiplyOp(a, b, t, &workset, &ignore); /* a=b*0.5 */ 2985 } /* loop */ 2986 2987 /* Here, 0.1 <= a < 1 [Hull], and a has maxp digits */ 2988 /* now reduce to length, etc.; this needs to be done with a */ 2989 /* having the correct exponent so as to handle subnormals */ 2990 /* correctly */ 2991 approxset=*set; /* get emin, emax, etc. */ 2992 approxset.round=DEC_ROUND_HALF_EVEN; 2993 a->exponent+=exp/2; /* set correct exponent */ 2994 rstatus=0; /* clear status */ 2995 residue=0; /* .. and accumulator */ 2996 decCopyFit(a, a, &approxset, &residue, &rstatus); /* reduce (if needed) */ 2997 decFinish(a, &approxset, &residue, &rstatus); /* clean and finalize */ 2998 2999 /* Overflow was possible if the input exponent was out-of-range, */ 3000 /* in which case quit */ 3001 if (rstatus&DEC_Overflow) { 3002 status=rstatus; /* use the status as-is */ 3003 uprv_decNumberCopy(res, a); /* copy to result */ 3004 break; 3005 } 3006 3007 /* Preserve status except Inexact/Rounded */ 3008 status|=(rstatus & ~(DEC_Rounded|DEC_Inexact)); 3009 3010 /* Carry out the Hull correction */ 3011 a->exponent-=exp/2; /* back to 0.1->1 */ 3012 3013 /* a is now at final precision and within 1 ulp of the properly */ 3014 /* rounded square root of f; to ensure proper rounding, compare */ 3015 /* squares of (a - l/2 ulp) and (a + l/2 ulp) with f. */ 3016 /* Here workset.digits=maxp and t=0.5, and a->digits determines */ 3017 /* the ulp */ 3018 workset.digits--; /* maxp-1 is OK now */ 3019 t->exponent=-a->digits-1; /* make 0.5 ulp */ 3020 decAddOp(b, a, t, &workset, DECNEG, &ignore); /* b = a - 0.5 ulp */ 3021 workset.round=DEC_ROUND_UP; 3022 decMultiplyOp(b, b, b, &workset, &ignore); /* b = mulru(b, b) */ 3023 decCompareOp(b, f, b, &workset, COMPARE, &ignore); /* b ? f, reversed */ 3024 if (decNumberIsNegative(b)) { /* f < b [i.e., b > f] */ 3025 /* this is the more common adjustment, though both are rare */ 3026 t->exponent++; /* make 1.0 ulp */ 3027 t->lsu[0]=1; /* .. */ 3028 decAddOp(a, a, t, &workset, DECNEG, &ignore); /* a = a - 1 ulp */ 3029 /* assign to approx [round to length] */ 3030 approxset.emin-=exp/2; /* adjust to match a */ 3031 approxset.emax-=exp/2; 3032 decAddOp(a, &dzero, a, &approxset, 0, &ignore); 3033 } 3034 else { 3035 decAddOp(b, a, t, &workset, 0, &ignore); /* b = a + 0.5 ulp */ 3036 workset.round=DEC_ROUND_DOWN; 3037 decMultiplyOp(b, b, b, &workset, &ignore); /* b = mulrd(b, b) */ 3038 decCompareOp(b, b, f, &workset, COMPARE, &ignore); /* b ? f */ 3039 if (decNumberIsNegative(b)) { /* b < f */ 3040 t->exponent++; /* make 1.0 ulp */ 3041 t->lsu[0]=1; /* .. */ 3042 decAddOp(a, a, t, &workset, 0, &ignore); /* a = a + 1 ulp */ 3043 /* assign to approx [round to length] */ 3044 approxset.emin-=exp/2; /* adjust to match a */ 3045 approxset.emax-=exp/2; 3046 decAddOp(a, &dzero, a, &approxset, 0, &ignore); 3047 } 3048 } 3049 /* [no errors are possible in the above, and rounding/inexact during */ 3050 /* estimation are irrelevant, so status was not accumulated] */ 3051 3052 /* Here, 0.1 <= a < 1 (still), so adjust back */ 3053 a->exponent+=exp/2; /* set correct exponent */ 3054 3055 /* count droppable zeros [after any subnormal rounding] by */ 3056 /* trimming a copy */ 3057 uprv_decNumberCopy(b, a); 3058 decTrim(b, set, 1, 1, &dropped); /* [drops trailing zeros] */ 3059 3060 /* Set Inexact and Rounded. The answer can only be exact if */ 3061 /* it is short enough so that squaring it could fit in workp */ 3062 /* digits, so this is the only (relatively rare) condition that */ 3063 /* a careful check is needed */ 3064 if (b->digits*2-1 > workp) { /* cannot fit */ 3065 status|=DEC_Inexact|DEC_Rounded; 3066 } 3067 else { /* could be exact/unrounded */ 3068 uInt mstatus=0; /* local status */ 3069 decMultiplyOp(b, b, b, &workset, &mstatus); /* try the multiply */ 3070 if (mstatus&DEC_Overflow) { /* result just won't fit */ 3071 status|=DEC_Inexact|DEC_Rounded; 3072 } 3073 else { /* plausible */ 3074 decCompareOp(t, b, rhs, &workset, COMPARE, &mstatus); /* b ? rhs */ 3075 if (!ISZERO(t)) status|=DEC_Inexact|DEC_Rounded; /* not equal */ 3076 else { /* is Exact */ 3077 /* here, dropped is the count of trailing zeros in 'a' */ 3078 /* use closest exponent to ideal... */ 3079 Int todrop=ideal-a->exponent; /* most that can be dropped */ 3080 if (todrop<0) status|=DEC_Rounded; /* ideally would add 0s */ 3081 else { /* unrounded */ 3082 /* there are some to drop, but emax may not allow all */ 3083 Int maxexp=set->emax-set->digits+1; 3084 Int maxdrop=maxexp-a->exponent; 3085 if (todrop>maxdrop && set->clamp) { /* apply clamping */ 3086 todrop=maxdrop; 3087 status|=DEC_Clamped; 3088 } 3089 if (dropped<todrop) { /* clamp to those available */ 3090 todrop=dropped; 3091 status|=DEC_Clamped; 3092 } 3093 if (todrop>0) { /* have some to drop */ 3094 decShiftToLeast(a->lsu, D2U(a->digits), todrop); 3095 a->exponent+=todrop; /* maintain numerical value */ 3096 a->digits-=todrop; /* new length */ 3097 } 3098 } 3099 } 3100 } 3101 } 3102 3103 /* double-check Underflow, as perhaps the result could not have */ 3104 /* been subnormal (initial argument too big), or it is now Exact */ 3105 if (status&DEC_Underflow) { 3106 Int ae=rhs->exponent+rhs->digits-1; /* adjusted exponent */ 3107 /* check if truly subnormal */ 3108 #if DECEXTFLAG /* DEC_Subnormal too */ 3109 if (ae>=set->emin*2) status&=~(DEC_Subnormal|DEC_Underflow); 3110 #else 3111 if (ae>=set->emin*2) status&=~DEC_Underflow; 3112 #endif 3113 /* check if truly inexact */ 3114 if (!(status&DEC_Inexact)) status&=~DEC_Underflow; 3115 } 3116 3117 uprv_decNumberCopy(res, a); /* a is now the result */ 3118 } while(0); /* end protected */ 3119 3120 if (allocbuff!=NULL) free(allocbuff); /* drop any storage used */ 3121 if (allocbufa!=NULL) free(allocbufa); /* .. */ 3122 if (allocbufb!=NULL) free(allocbufb); /* .. */ 3123 #if DECSUBSET 3124 if (allocrhs !=NULL) free(allocrhs); /* .. */ 3125 #endif 3126 if (status!=0) decStatus(res, status, set);/* then report status */ 3127 #if DECCHECK 3128 decCheckInexact(res, set); 3129 #endif 3130 return res; 3131 } /* decNumberSquareRoot */ 3132 3133 /* ------------------------------------------------------------------ */ 3134 /* decNumberSubtract -- subtract two Numbers */ 3135 /* */ 3136 /* This computes C = A - B */ 3137 /* */ 3138 /* res is C, the result. C may be A and/or B (e.g., X=X-X) */ 3139 /* lhs is A */ 3140 /* rhs is B */ 3141 /* set is the context */ 3142 /* */ 3143 /* C must have space for set->digits digits. */ 3144 /* ------------------------------------------------------------------ */ 3145 U_CAPI decNumber * U_EXPORT2 uprv_decNumberSubtract(decNumber *res, const decNumber *lhs, 3146 const decNumber *rhs, decContext *set) { 3147 uInt status=0; /* accumulator */ 3148 3149 decAddOp(res, lhs, rhs, set, DECNEG, &status); 3150 if (status!=0) decStatus(res, status, set); 3151 #if DECCHECK 3152 decCheckInexact(res, set); 3153 #endif 3154 return res; 3155 } /* decNumberSubtract */ 3156 3157 /* ------------------------------------------------------------------ */ 3158 /* decNumberToIntegralExact -- round-to-integral-value with InExact */ 3159 /* decNumberToIntegralValue -- round-to-integral-value */ 3160 /* */ 3161 /* res is the result */ 3162 /* rhs is input number */ 3163 /* set is the context */ 3164 /* */ 3165 /* res must have space for any value of rhs. */ 3166 /* */ 3167 /* This implements the IEEE special operators and therefore treats */ 3168 /* special values as valid. For finite numbers it returns */ 3169 /* rescale(rhs, 0) if rhs->exponent is <0. */ 3170 /* Otherwise the result is rhs (so no error is possible, except for */ 3171 /* sNaN). */ 3172 /* */ 3173 /* The context is used for rounding mode and status after sNaN, but */ 3174 /* the digits setting is ignored. The Exact version will signal */ 3175 /* Inexact if the result differs numerically from rhs; the other */ 3176 /* never signals Inexact. */ 3177 /* ------------------------------------------------------------------ */ 3178 U_CAPI decNumber * U_EXPORT2 uprv_decNumberToIntegralExact(decNumber *res, const decNumber *rhs, 3179 decContext *set) { 3180 decNumber dn; 3181 decContext workset; /* working context */ 3182 uInt status=0; /* accumulator */ 3183 3184 #if DECCHECK 3185 if (decCheckOperands(res, DECUNUSED, rhs, set)) return res; 3186 #endif 3187 3188 /* handle infinities and NaNs */ 3189 if (SPECIALARG) { 3190 if (decNumberIsInfinite(rhs)) uprv_decNumberCopy(res, rhs); /* an Infinity */ 3191 else decNaNs(res, rhs, NULL, set, &status); /* a NaN */ 3192 } 3193 else { /* finite */ 3194 /* have a finite number; no error possible (res must be big enough) */ 3195 if (rhs->exponent>=0) return uprv_decNumberCopy(res, rhs); 3196 /* that was easy, but if negative exponent there is work to do... */ 3197 workset=*set; /* clone rounding, etc. */ 3198 workset.digits=rhs->digits; /* no length rounding */ 3199 workset.traps=0; /* no traps */ 3200 uprv_decNumberZero(&dn); /* make a number with exponent 0 */ 3201 uprv_decNumberQuantize(res, rhs, &dn, &workset); 3202 status|=workset.status; 3203 } 3204 if (status!=0) decStatus(res, status, set); 3205 return res; 3206 } /* decNumberToIntegralExact */ 3207 3208 U_CAPI decNumber * U_EXPORT2 uprv_decNumberToIntegralValue(decNumber *res, const decNumber *rhs, 3209 decContext *set) { 3210 decContext workset=*set; /* working context */ 3211 workset.traps=0; /* no traps */ 3212 uprv_decNumberToIntegralExact(res, rhs, &workset); 3213 /* this never affects set, except for sNaNs; NaN will have been set */ 3214 /* or propagated already, so no need to call decStatus */ 3215 set->status|=workset.status&DEC_Invalid_operation; 3216 return res; 3217 } /* decNumberToIntegralValue */ 3218 3219 /* ------------------------------------------------------------------ */ 3220 /* decNumberXor -- XOR two Numbers, digitwise */ 3221 /* */ 3222 /* This computes C = A ^ B */ 3223 /* */ 3224 /* res is C, the result. C may be A and/or B (e.g., X=X^X) */ 3225 /* lhs is A */ 3226 /* rhs is B */ 3227 /* set is the context (used for result length and error report) */ 3228 /* */ 3229 /* C must have space for set->digits digits. */ 3230 /* */ 3231 /* Logical function restrictions apply (see above); a NaN is */ 3232 /* returned with Invalid_operation if a restriction is violated. */ 3233 /* ------------------------------------------------------------------ */ 3234 U_CAPI decNumber * U_EXPORT2 uprv_decNumberXor(decNumber *res, const decNumber *lhs, 3235 const decNumber *rhs, decContext *set) { 3236 const Unit *ua, *ub; /* -> operands */ 3237 const Unit *msua, *msub; /* -> operand msus */ 3238 Unit *uc, *msuc; /* -> result and its msu */ 3239 Int msudigs; /* digits in res msu */ 3240 #if DECCHECK 3241 if (decCheckOperands(res, lhs, rhs, set)) return res; 3242 #endif 3243 3244 if (lhs->exponent!=0 || decNumberIsSpecial(lhs) || decNumberIsNegative(lhs) 3245 || rhs->exponent!=0 || decNumberIsSpecial(rhs) || decNumberIsNegative(rhs)) { 3246 decStatus(res, DEC_Invalid_operation, set); 3247 return res; 3248 } 3249 /* operands are valid */ 3250 ua=lhs->lsu; /* bottom-up */ 3251 ub=rhs->lsu; /* .. */ 3252 uc=res->lsu; /* .. */ 3253 msua=ua+D2U(lhs->digits)-1; /* -> msu of lhs */ 3254 msub=ub+D2U(rhs->digits)-1; /* -> msu of rhs */ 3255 msuc=uc+D2U(set->digits)-1; /* -> msu of result */ 3256 msudigs=MSUDIGITS(set->digits); /* [faster than remainder] */ 3257 for (; uc<=msuc; ua++, ub++, uc++) { /* Unit loop */ 3258 Unit a, b; /* extract units */ 3259 if (ua>msua) a=0; 3260 else a=*ua; 3261 if (ub>msub) b=0; 3262 else b=*ub; 3263 *uc=0; /* can now write back */ 3264 if (a|b) { /* maybe 1 bits to examine */ 3265 Int i, j; 3266 /* This loop could be unrolled and/or use BIN2BCD tables */ 3267 for (i=0; i<DECDPUN; i++) { 3268 if ((a^b)&1) *uc=*uc+(Unit)powers[i]; /* effect XOR */ 3269 j=a%10; 3270 a=a/10; 3271 j|=b%10; 3272 b=b/10; 3273 if (j>1) { 3274 decStatus(res, DEC_Invalid_operation, set); 3275 return res; 3276 } 3277 if (uc==msuc && i==msudigs-1) break; /* just did final digit */ 3278 } /* each digit */ 3279 } /* non-zero */ 3280 } /* each unit */ 3281 /* [here uc-1 is the msu of the result] */ 3282 res->digits=decGetDigits(res->lsu, uc-res->lsu); 3283 res->exponent=0; /* integer */ 3284 res->bits=0; /* sign=0 */ 3285 return res; /* [no status to set] */ 3286 } /* decNumberXor */ 3287 3288 3289 /* ================================================================== */ 3290 /* Utility routines */ 3291 /* ================================================================== */ 3292 3293 /* ------------------------------------------------------------------ */ 3294 /* decNumberClass -- return the decClass of a decNumber */ 3295 /* dn -- the decNumber to test */ 3296 /* set -- the context to use for Emin */ 3297 /* returns the decClass enum */ 3298 /* ------------------------------------------------------------------ */ 3299 enum decClass uprv_decNumberClass(const decNumber *dn, decContext *set) { 3300 if (decNumberIsSpecial(dn)) { 3301 if (decNumberIsQNaN(dn)) return DEC_CLASS_QNAN; 3302 if (decNumberIsSNaN(dn)) return DEC_CLASS_SNAN; 3303 /* must be an infinity */ 3304 if (decNumberIsNegative(dn)) return DEC_CLASS_NEG_INF; 3305 return DEC_CLASS_POS_INF; 3306 } 3307 /* is finite */ 3308 if (uprv_decNumberIsNormal(dn, set)) { /* most common */ 3309 if (decNumberIsNegative(dn)) return DEC_CLASS_NEG_NORMAL; 3310 return DEC_CLASS_POS_NORMAL; 3311 } 3312 /* is subnormal or zero */ 3313 if (decNumberIsZero(dn)) { /* most common */ 3314 if (decNumberIsNegative(dn)) return DEC_CLASS_NEG_ZERO; 3315 return DEC_CLASS_POS_ZERO; 3316 } 3317 if (decNumberIsNegative(dn)) return DEC_CLASS_NEG_SUBNORMAL; 3318 return DEC_CLASS_POS_SUBNORMAL; 3319 } /* decNumberClass */ 3320 3321 /* ------------------------------------------------------------------ */ 3322 /* decNumberClassToString -- convert decClass to a string */ 3323 /* */ 3324 /* eclass is a valid decClass */ 3325 /* returns a constant string describing the class (max 13+1 chars) */ 3326 /* ------------------------------------------------------------------ */ 3327 const char *uprv_decNumberClassToString(enum decClass eclass) { 3328 if (eclass==DEC_CLASS_POS_NORMAL) return DEC_ClassString_PN; 3329 if (eclass==DEC_CLASS_NEG_NORMAL) return DEC_ClassString_NN; 3330 if (eclass==DEC_CLASS_POS_ZERO) return DEC_ClassString_PZ; 3331 if (eclass==DEC_CLASS_NEG_ZERO) return DEC_ClassString_NZ; 3332 if (eclass==DEC_CLASS_POS_SUBNORMAL) return DEC_ClassString_PS; 3333 if (eclass==DEC_CLASS_NEG_SUBNORMAL) return DEC_ClassString_NS; 3334 if (eclass==DEC_CLASS_POS_INF) return DEC_ClassString_PI; 3335 if (eclass==DEC_CLASS_NEG_INF) return DEC_ClassString_NI; 3336 if (eclass==DEC_CLASS_QNAN) return DEC_ClassString_QN; 3337 if (eclass==DEC_CLASS_SNAN) return DEC_ClassString_SN; 3338 return DEC_ClassString_UN; /* Unknown */ 3339 } /* decNumberClassToString */ 3340 3341 /* ------------------------------------------------------------------ */ 3342 /* decNumberCopy -- copy a number */ 3343 /* */ 3344 /* dest is the target decNumber */ 3345 /* src is the source decNumber */ 3346 /* returns dest */ 3347 /* */ 3348 /* (dest==src is allowed and is a no-op) */ 3349 /* All fields are updated as required. This is a utility operation, */ 3350 /* so special values are unchanged and no error is possible. */ 3351 /* ------------------------------------------------------------------ */ 3352 U_CAPI decNumber * U_EXPORT2 uprv_decNumberCopy(decNumber *dest, const decNumber *src) { 3353 3354 #if DECCHECK 3355 if (src==NULL) return uprv_decNumberZero(dest); 3356 #endif 3357 3358 if (dest==src) return dest; /* no copy required */ 3359 3360 /* Use explicit assignments here as structure assignment could copy */ 3361 /* more than just the lsu (for small DECDPUN). This would not affect */ 3362 /* the value of the results, but could disturb test harness spill */ 3363 /* checking. */ 3364 dest->bits=src->bits; 3365 dest->exponent=src->exponent; 3366 dest->digits=src->digits; 3367 dest->lsu[0]=src->lsu[0]; 3368 if (src->digits>DECDPUN) { /* more Units to come */ 3369 const Unit *smsup, *s; /* work */ 3370 Unit *d; /* .. */ 3371 /* memcpy for the remaining Units would be safe as they cannot */ 3372 /* overlap. However, this explicit loop is faster in short cases. */ 3373 d=dest->lsu+1; /* -> first destination */ 3374 smsup=src->lsu+D2U(src->digits); /* -> source msu+1 */ 3375 for (s=src->lsu+1; s<smsup; s++, d++) *d=*s; 3376 } 3377 return dest; 3378 } /* decNumberCopy */ 3379 3380 /* ------------------------------------------------------------------ */ 3381 /* decNumberCopyAbs -- quiet absolute value operator */ 3382 /* */ 3383 /* This sets C = abs(A) */ 3384 /* */ 3385 /* res is C, the result. C may be A */ 3386 /* rhs is A */ 3387 /* */ 3388 /* C must have space for set->digits digits. */ 3389 /* No exception or error can occur; this is a quiet bitwise operation.*/ 3390 /* See also decNumberAbs for a checking version of this. */ 3391 /* ------------------------------------------------------------------ */ 3392 U_CAPI decNumber * U_EXPORT2 uprv_decNumberCopyAbs(decNumber *res, const decNumber *rhs) { 3393 #if DECCHECK 3394 if (decCheckOperands(res, DECUNUSED, rhs, DECUNCONT)) return res; 3395 #endif 3396 uprv_decNumberCopy(res, rhs); 3397 res->bits&=~DECNEG; /* turn off sign */ 3398 return res; 3399 } /* decNumberCopyAbs */ 3400 3401 /* ------------------------------------------------------------------ */ 3402 /* decNumberCopyNegate -- quiet negate value operator */ 3403 /* */ 3404 /* This sets C = negate(A) */ 3405 /* */ 3406 /* res is C, the result. C may be A */ 3407 /* rhs is A */ 3408 /* */ 3409 /* C must have space for set->digits digits. */ 3410 /* No exception or error can occur; this is a quiet bitwise operation.*/ 3411 /* See also decNumberMinus for a checking version of this. */ 3412 /* ------------------------------------------------------------------ */ 3413 U_CAPI decNumber * U_EXPORT2 uprv_decNumberCopyNegate(decNumber *res, const decNumber *rhs) { 3414 #if DECCHECK 3415 if (decCheckOperands(res, DECUNUSED, rhs, DECUNCONT)) return res; 3416 #endif 3417 uprv_decNumberCopy(res, rhs); 3418 res->bits^=DECNEG; /* invert the sign */ 3419 return res; 3420 } /* decNumberCopyNegate */ 3421 3422 /* ------------------------------------------------------------------ */ 3423 /* decNumberCopySign -- quiet copy and set sign operator */ 3424 /* */ 3425 /* This sets C = A with the sign of B */ 3426 /* */ 3427 /* res is C, the result. C may be A */ 3428 /* lhs is A */ 3429 /* rhs is B */ 3430 /* */ 3431 /* C must have space for set->digits digits. */ 3432 /* No exception or error can occur; this is a quiet bitwise operation.*/ 3433 /* ------------------------------------------------------------------ */ 3434 U_CAPI decNumber * U_EXPORT2 uprv_decNumberCopySign(decNumber *res, const decNumber *lhs, 3435 const decNumber *rhs) { 3436 uByte sign; /* rhs sign */ 3437 #if DECCHECK 3438 if (decCheckOperands(res, DECUNUSED, rhs, DECUNCONT)) return res; 3439 #endif 3440 sign=rhs->bits & DECNEG; /* save sign bit */ 3441 uprv_decNumberCopy(res, lhs); 3442 res->bits&=~DECNEG; /* clear the sign */ 3443 res->bits|=sign; /* set from rhs */ 3444 return res; 3445 } /* decNumberCopySign */ 3446 3447 /* ------------------------------------------------------------------ */ 3448 /* decNumberGetBCD -- get the coefficient in BCD8 */ 3449 /* dn is the source decNumber */ 3450 /* bcd is the uInt array that will receive dn->digits BCD bytes, */ 3451 /* most-significant at offset 0 */ 3452 /* returns bcd */ 3453 /* */ 3454 /* bcd must have at least dn->digits bytes. No error is possible; if */ 3455 /* dn is a NaN or Infinite, digits must be 1 and the coefficient 0. */ 3456 /* ------------------------------------------------------------------ */ 3457 U_CAPI uByte * U_EXPORT2 uprv_decNumberGetBCD(const decNumber *dn, uByte *bcd) { 3458 uByte *ub=bcd+dn->digits-1; /* -> lsd */ 3459 const Unit *up=dn->lsu; /* Unit pointer, -> lsu */ 3460 3461 #if DECDPUN==1 /* trivial simple copy */ 3462 for (; ub>=bcd; ub--, up++) *ub=*up; 3463 #else /* chopping needed */ 3464 uInt u=*up; /* work */ 3465 uInt cut=DECDPUN; /* downcounter through unit */ 3466 for (; ub>=bcd; ub--) { 3467 *ub=(uByte)(u%10); /* [*6554 trick inhibits, here] */ 3468 u=u/10; 3469 cut--; 3470 if (cut>0) continue; /* more in this unit */ 3471 up++; 3472 u=*up; 3473 cut=DECDPUN; 3474 } 3475 #endif 3476 return bcd; 3477 } /* decNumberGetBCD */ 3478 3479 /* ------------------------------------------------------------------ */ 3480 /* decNumberSetBCD -- set (replace) the coefficient from BCD8 */ 3481 /* dn is the target decNumber */ 3482 /* bcd is the uInt array that will source n BCD bytes, most- */ 3483 /* significant at offset 0 */ 3484 /* n is the number of digits in the source BCD array (bcd) */ 3485 /* returns dn */ 3486 /* */ 3487 /* dn must have space for at least n digits. No error is possible; */ 3488 /* if dn is a NaN, or Infinite, or is to become a zero, n must be 1 */ 3489 /* and bcd[0] zero. */ 3490 /* ------------------------------------------------------------------ */ 3491 U_CAPI decNumber * U_EXPORT2 uprv_decNumberSetBCD(decNumber *dn, const uByte *bcd, uInt n) { 3492 Unit *up=dn->lsu+D2U(dn->digits)-1; /* -> msu [target pointer] */ 3493 const uByte *ub=bcd; /* -> source msd */ 3494 3495 #if DECDPUN==1 /* trivial simple copy */ 3496 for (; ub<bcd+n; ub++, up--) *up=*ub; 3497 #else /* some assembly needed */ 3498 /* calculate how many digits in msu, and hence first cut */ 3499 Int cut=MSUDIGITS(n); /* [faster than remainder] */ 3500 for (;up>=dn->lsu; up--) { /* each Unit from msu */ 3501 *up=0; /* will take <=DECDPUN digits */ 3502 for (; cut>0; ub++, cut--) *up=X10(*up)+*ub; 3503 cut=DECDPUN; /* next Unit has all digits */ 3504 } 3505 #endif 3506 dn->digits=n; /* set digit count */ 3507 return dn; 3508 } /* decNumberSetBCD */ 3509 3510 /* ------------------------------------------------------------------ */ 3511 /* decNumberIsNormal -- test normality of a decNumber */ 3512 /* dn is the decNumber to test */ 3513 /* set is the context to use for Emin */ 3514 /* returns 1 if |dn| is finite and >=Nmin, 0 otherwise */ 3515 /* ------------------------------------------------------------------ */ 3516 Int uprv_decNumberIsNormal(const decNumber *dn, decContext *set) { 3517 Int ae; /* adjusted exponent */ 3518 #if DECCHECK 3519 if (decCheckOperands(DECUNRESU, DECUNUSED, dn, set)) return 0; 3520 #endif 3521 3522 if (decNumberIsSpecial(dn)) return 0; /* not finite */ 3523 if (decNumberIsZero(dn)) return 0; /* not non-zero */ 3524 3525 ae=dn->exponent+dn->digits-1; /* adjusted exponent */ 3526 if (ae<set->emin) return 0; /* is subnormal */ 3527 return 1; 3528 } /* decNumberIsNormal */ 3529 3530 /* ------------------------------------------------------------------ */ 3531 /* decNumberIsSubnormal -- test subnormality of a decNumber */ 3532 /* dn is the decNumber to test */ 3533 /* set is the context to use for Emin */ 3534 /* returns 1 if |dn| is finite, non-zero, and <Nmin, 0 otherwise */ 3535 /* ------------------------------------------------------------------ */ 3536 Int uprv_decNumberIsSubnormal(const decNumber *dn, decContext *set) { 3537 Int ae; /* adjusted exponent */ 3538 #if DECCHECK 3539 if (decCheckOperands(DECUNRESU, DECUNUSED, dn, set)) return 0; 3540 #endif 3541 3542 if (decNumberIsSpecial(dn)) return 0; /* not finite */ 3543 if (decNumberIsZero(dn)) return 0; /* not non-zero */ 3544 3545 ae=dn->exponent+dn->digits-1; /* adjusted exponent */ 3546 if (ae<set->emin) return 1; /* is subnormal */ 3547 return 0; 3548 } /* decNumberIsSubnormal */ 3549 3550 /* ------------------------------------------------------------------ */ 3551 /* decNumberTrim -- remove insignificant zeros */ 3552 /* */ 3553 /* dn is the number to trim */ 3554 /* returns dn */ 3555 /* */ 3556 /* All fields are updated as required. This is a utility operation, */ 3557 /* so special values are unchanged and no error is possible. The */ 3558 /* zeros are removed unconditionally. */ 3559 /* ------------------------------------------------------------------ */ 3560 U_CAPI decNumber * U_EXPORT2 uprv_decNumberTrim(decNumber *dn) { 3561 Int dropped; /* work */ 3562 decContext set; /* .. */ 3563 #if DECCHECK 3564 if (decCheckOperands(DECUNRESU, DECUNUSED, dn, DECUNCONT)) return dn; 3565 #endif 3566 uprv_decContextDefault(&set, DEC_INIT_BASE); /* clamp=0 */ 3567 return decTrim(dn, &set, 0, 1, &dropped); 3568 } /* decNumberTrim */ 3569 3570 /* ------------------------------------------------------------------ */ 3571 /* decNumberVersion -- return the name and version of this module */ 3572 /* */ 3573 /* No error is possible. */ 3574 /* ------------------------------------------------------------------ */ 3575 const char * uprv_decNumberVersion(void) { 3576 return DECVERSION; 3577 } /* decNumberVersion */ 3578 3579 /* ------------------------------------------------------------------ */ 3580 /* decNumberZero -- set a number to 0 */ 3581 /* */ 3582 /* dn is the number to set, with space for one digit */ 3583 /* returns dn */ 3584 /* */ 3585 /* No error is possible. */ 3586 /* ------------------------------------------------------------------ */ 3587 /* Memset is not used as it is much slower in some environments. */ 3588 U_CAPI decNumber * U_EXPORT2 uprv_decNumberZero(decNumber *dn) { 3589 3590 #if DECCHECK 3591 if (decCheckOperands(dn, DECUNUSED, DECUNUSED, DECUNCONT)) return dn; 3592 #endif 3593 3594 dn->bits=0; 3595 dn->exponent=0; 3596 dn->digits=1; 3597 dn->lsu[0]=0; 3598 return dn; 3599 } /* decNumberZero */ 3600 3601 /* ================================================================== */ 3602 /* Local routines */ 3603 /* ================================================================== */ 3604 3605 /* ------------------------------------------------------------------ */ 3606 /* decToString -- lay out a number into a string */ 3607 /* */ 3608 /* dn is the number to lay out */ 3609 /* string is where to lay out the number */ 3610 /* eng is 1 if Engineering, 0 if Scientific */ 3611 /* */ 3612 /* string must be at least dn->digits+14 characters long */ 3613 /* No error is possible. */ 3614 /* */ 3615 /* Note that this routine can generate a -0 or 0.000. These are */ 3616 /* never generated in subset to-number or arithmetic, but can occur */ 3617 /* in non-subset arithmetic (e.g., -1*0 or 1.234-1.234). */ 3618 /* ------------------------------------------------------------------ */ 3619 /* If DECCHECK is enabled the string "?" is returned if a number is */ 3620 /* invalid. */ 3621 static void decToString(const decNumber *dn, char *string, Flag eng) { 3622 Int exp=dn->exponent; /* local copy */ 3623 Int e; /* E-part value */ 3624 Int pre; /* digits before the '.' */ 3625 Int cut; /* for counting digits in a Unit */ 3626 char *c=string; /* work [output pointer] */ 3627 const Unit *up=dn->lsu+D2U(dn->digits)-1; /* -> msu [input pointer] */ 3628 uInt u, pow; /* work */ 3629 3630 #if DECCHECK 3631 if (decCheckOperands(DECUNRESU, dn, DECUNUSED, DECUNCONT)) { 3632 strcpy(string, "?"); 3633 return;} 3634 #endif 3635 3636 if (decNumberIsNegative(dn)) { /* Negatives get a minus */ 3637 *c='-'; 3638 c++; 3639 } 3640 if (dn->bits&DECSPECIAL) { /* Is a special value */ 3641 if (decNumberIsInfinite(dn)) { 3642 strcpy(c, "Inf"); 3643 strcpy(c+3, "inity"); 3644 return;} 3645 /* a NaN */ 3646 if (dn->bits&DECSNAN) { /* signalling NaN */ 3647 *c='s'; 3648 c++; 3649 } 3650 strcpy(c, "NaN"); 3651 c+=3; /* step past */ 3652 /* if not a clean non-zero coefficient, that's all there is in a */ 3653 /* NaN string */ 3654 if (exp!=0 || (*dn->lsu==0 && dn->digits==1)) return; 3655 /* [drop through to add integer] */ 3656 } 3657 3658 /* calculate how many digits in msu, and hence first cut */ 3659 cut=MSUDIGITS(dn->digits); /* [faster than remainder] */ 3660 cut--; /* power of ten for digit */ 3661 3662 if (exp==0) { /* simple integer [common fastpath] */ 3663 for (;up>=dn->lsu; up--) { /* each Unit from msu */ 3664 u=*up; /* contains DECDPUN digits to lay out */ 3665 for (; cut>=0; c++, cut--) TODIGIT(u, cut, c, pow); 3666 cut=DECDPUN-1; /* next Unit has all digits */ 3667 } 3668 *c='\0'; /* terminate the string */ 3669 return;} 3670 3671 /* non-0 exponent -- assume plain form */ 3672 pre=dn->digits+exp; /* digits before '.' */ 3673 e=0; /* no E */ 3674 if ((exp>0) || (pre<-5)) { /* need exponential form */ 3675 e=exp+dn->digits-1; /* calculate E value */ 3676 pre=1; /* assume one digit before '.' */ 3677 if (eng && (e!=0)) { /* engineering: may need to adjust */ 3678 Int adj; /* adjustment */ 3679 /* The C remainder operator is undefined for negative numbers, so */ 3680 /* a positive remainder calculation must be used here */ 3681 if (e<0) { 3682 adj=(-e)%3; 3683 if (adj!=0) adj=3-adj; 3684 } 3685 else { /* e>0 */ 3686 adj=e%3; 3687 } 3688 e=e-adj; 3689 /* if dealing with zero still produce an exponent which is a */ 3690 /* multiple of three, as expected, but there will only be the */ 3691 /* one zero before the E, still. Otherwise note the padding. */ 3692 if (!ISZERO(dn)) pre+=adj; 3693 else { /* is zero */ 3694 if (adj!=0) { /* 0.00Esnn needed */ 3695 e=e+3; 3696 pre=-(2-adj); 3697 } 3698 } /* zero */ 3699 } /* eng */ 3700 } /* need exponent */ 3701 3702 /* lay out the digits of the coefficient, adding 0s and . as needed */ 3703 u=*up; 3704 if (pre>0) { /* xxx.xxx or xx00 (engineering) form */ 3705 Int n=pre; 3706 for (; pre>0; pre--, c++, cut--) { 3707 if (cut<0) { /* need new Unit */ 3708 if (up==dn->lsu) break; /* out of input digits (pre>digits) */ 3709 up--; 3710 cut=DECDPUN-1; 3711 u=*up; 3712 } 3713 TODIGIT(u, cut, c, pow); 3714 } 3715 if (n<dn->digits) { /* more to come, after '.' */ 3716 *c='.'; c++; 3717 for (;; c++, cut--) { 3718 if (cut<0) { /* need new Unit */ 3719 if (up==dn->lsu) break; /* out of input digits */ 3720 up--; 3721 cut=DECDPUN-1; 3722 u=*up; 3723 } 3724 TODIGIT(u, cut, c, pow); 3725 } 3726 } 3727 else for (; pre>0; pre--, c++) *c='0'; /* 0 padding (for engineering) needed */ 3728 } 3729 else { /* 0.xxx or 0.000xxx form */ 3730 *c='0'; c++; 3731 *c='.'; c++; 3732 for (; pre<0; pre++, c++) *c='0'; /* add any 0's after '.' */ 3733 for (; ; c++, cut--) { 3734 if (cut<0) { /* need new Unit */ 3735 if (up==dn->lsu) break; /* out of input digits */ 3736 up--; 3737 cut=DECDPUN-1; 3738 u=*up; 3739 } 3740 TODIGIT(u, cut, c, pow); 3741 } 3742 } 3743 3744 /* Finally add the E-part, if needed. It will never be 0, has a 3745 base maximum and minimum of +999999999 through -999999999, but 3746 could range down to -1999999998 for anormal numbers */ 3747 if (e!=0) { 3748 Flag had=0; /* 1=had non-zero */ 3749 *c='E'; c++; 3750 *c='+'; c++; /* assume positive */ 3751 u=e; /* .. */ 3752 if (e<0) { 3753 *(c-1)='-'; /* oops, need - */ 3754 u=-e; /* uInt, please */ 3755 } 3756 /* lay out the exponent [_itoa or equivalent is not ANSI C] */ 3757 for (cut=9; cut>=0; cut--) { 3758 TODIGIT(u, cut, c, pow); 3759 if (*c=='0' && !had) continue; /* skip leading zeros */ 3760 had=1; /* had non-0 */ 3761 c++; /* step for next */ 3762 } /* cut */ 3763 } 3764 *c='\0'; /* terminate the string (all paths) */ 3765 return; 3766 } /* decToString */ 3767 3768 /* ------------------------------------------------------------------ */ 3769 /* decAddOp -- add/subtract operation */ 3770 /* */ 3771 /* This computes C = A + B */ 3772 /* */ 3773 /* res is C, the result. C may be A and/or B (e.g., X=X+X) */ 3774 /* lhs is A */ 3775 /* rhs is B */ 3776 /* set is the context */ 3777 /* negate is DECNEG if rhs should be negated, or 0 otherwise */ 3778 /* status accumulates status for the caller */ 3779 /* */ 3780 /* C must have space for set->digits digits. */ 3781 /* Inexact in status must be 0 for correct Exact zero sign in result */ 3782 /* ------------------------------------------------------------------ */ 3783 /* If possible, the coefficient is calculated directly into C. */ 3784 /* However, if: */ 3785 /* -- a digits+1 calculation is needed because the numbers are */ 3786 /* unaligned and span more than set->digits digits */ 3787 /* -- a carry to digits+1 digits looks possible */ 3788 /* -- C is the same as A or B, and the result would destructively */ 3789 /* overlap the A or B coefficient */ 3790 /* then the result must be calculated into a temporary buffer. In */ 3791 /* this case a local (stack) buffer is used if possible, and only if */ 3792 /* too long for that does malloc become the final resort. */ 3793 /* */ 3794 /* Misalignment is handled as follows: */ 3795 /* Apad: (AExp>BExp) Swap operands and proceed as for BExp>AExp. */ 3796 /* BPad: Apply the padding by a combination of shifting (whole */ 3797 /* units) and multiplication (part units). */ 3798 /* */ 3799 /* Addition, especially x=x+1, is speed-critical. */ 3800 /* The static buffer is larger than might be expected to allow for */ 3801 /* calls from higher-level funtions (notable exp). */ 3802 /* ------------------------------------------------------------------ */ 3803 static decNumber * decAddOp(decNumber *res, const decNumber *lhs, 3804 const decNumber *rhs, decContext *set, 3805 uByte negate, uInt *status) { 3806 #if DECSUBSET 3807 decNumber *alloclhs=NULL; /* non-NULL if rounded lhs allocated */ 3808 decNumber *allocrhs=NULL; /* .., rhs */ 3809 #endif 3810 Int rhsshift; /* working shift (in Units) */ 3811 Int maxdigits; /* longest logical length */ 3812 Int mult; /* multiplier */ 3813 Int residue; /* rounding accumulator */ 3814 uByte bits; /* result bits */ 3815 Flag diffsign; /* non-0 if arguments have different sign */ 3816 Unit *acc; /* accumulator for result */ 3817 Unit accbuff[SD2U(DECBUFFER*2+20)]; /* local buffer [*2+20 reduces many */ 3818 /* allocations when called from */ 3819 /* other operations, notable exp] */ 3820 Unit *allocacc=NULL; /* -> allocated acc buffer, iff allocated */ 3821 Int reqdigits=set->digits; /* local copy; requested DIGITS */ 3822 Int padding; /* work */ 3823 3824 #if DECCHECK 3825 if (decCheckOperands(res, lhs, rhs, set)) return res; 3826 #endif 3827 3828 do { /* protect allocated storage */ 3829 #if DECSUBSET 3830 if (!set->extended) { 3831 /* reduce operands and set lostDigits status, as needed */ 3832 if (lhs->digits>reqdigits) { 3833 alloclhs=decRoundOperand(lhs, set, status); 3834 if (alloclhs==NULL) break; 3835 lhs=alloclhs; 3836 } 3837 if (rhs->digits>reqdigits) { 3838 allocrhs=decRoundOperand(rhs, set, status); 3839 if (allocrhs==NULL) break; 3840 rhs=allocrhs; 3841 } 3842 } 3843 #endif 3844 /* [following code does not require input rounding] */ 3845 3846 /* note whether signs differ [used all paths] */ 3847 diffsign=(Flag)((lhs->bits^rhs->bits^negate)&DECNEG); 3848 3849 /* handle infinities and NaNs */ 3850 if (SPECIALARGS) { /* a special bit set */ 3851 if (SPECIALARGS & (DECSNAN | DECNAN)) /* a NaN */ 3852 decNaNs(res, lhs, rhs, set, status); 3853 else { /* one or two infinities */ 3854 if (decNumberIsInfinite(lhs)) { /* LHS is infinity */ 3855 /* two infinities with different signs is invalid */ 3856 if (decNumberIsInfinite(rhs) && diffsign) { 3857 *status|=DEC_Invalid_operation; 3858 break; 3859 } 3860 bits=lhs->bits & DECNEG; /* get sign from LHS */ 3861 } 3862 else bits=(rhs->bits^negate) & DECNEG;/* RHS must be Infinity */ 3863 bits|=DECINF; 3864 uprv_decNumberZero(res); 3865 res->bits=bits; /* set +/- infinity */ 3866 } /* an infinity */ 3867 break; 3868 } 3869 3870 /* Quick exit for add 0s; return the non-0, modified as need be */ 3871 if (ISZERO(lhs)) { 3872 Int adjust; /* work */ 3873 Int lexp=lhs->exponent; /* save in case LHS==RES */ 3874 bits=lhs->bits; /* .. */ 3875 residue=0; /* clear accumulator */ 3876 decCopyFit(res, rhs, set, &residue, status); /* copy (as needed) */ 3877 res->bits^=negate; /* flip if rhs was negated */ 3878 #if DECSUBSET 3879 if (set->extended) { /* exponents on zeros count */ 3880 #endif 3881 /* exponent will be the lower of the two */ 3882 adjust=lexp-res->exponent; /* adjustment needed [if -ve] */ 3883 if (ISZERO(res)) { /* both 0: special IEEE 754 rules */ 3884 if (adjust<0) res->exponent=lexp; /* set exponent */ 3885 /* 0-0 gives +0 unless rounding to -infinity, and -0-0 gives -0 */ 3886 if (diffsign) { 3887 if (set->round!=DEC_ROUND_FLOOR) res->bits=0; 3888 else res->bits=DECNEG; /* preserve 0 sign */ 3889 } 3890 } 3891 else { /* non-0 res */ 3892 if (adjust<0) { /* 0-padding needed */ 3893 if ((res->digits-adjust)>set->digits) { 3894 adjust=res->digits-set->digits; /* to fit exactly */ 3895 *status|=DEC_Rounded; /* [but exact] */ 3896 } 3897 res->digits=decShiftToMost(res->lsu, res->digits, -adjust); 3898 res->exponent+=adjust; /* set the exponent. */ 3899 } 3900 } /* non-0 res */ 3901 #if DECSUBSET 3902 } /* extended */ 3903 #endif 3904 decFinish(res, set, &residue, status); /* clean and finalize */ 3905 break;} 3906 3907 if (ISZERO(rhs)) { /* [lhs is non-zero] */ 3908 Int adjust; /* work */ 3909 Int rexp=rhs->exponent; /* save in case RHS==RES */ 3910 bits=rhs->bits; /* be clean */ 3911 residue=0; /* clear accumulator */ 3912 decCopyFit(res, lhs, set, &residue, status); /* copy (as needed) */ 3913 #if DECSUBSET 3914 if (set->extended) { /* exponents on zeros count */ 3915 #endif 3916 /* exponent will be the lower of the two */ 3917 /* [0-0 case handled above] */ 3918 adjust=rexp-res->exponent; /* adjustment needed [if -ve] */ 3919 if (adjust<0) { /* 0-padding needed */ 3920 if ((res->digits-adjust)>set->digits) { 3921 adjust=res->digits-set->digits; /* to fit exactly */ 3922 *status|=DEC_Rounded; /* [but exact] */ 3923 } 3924 res->digits=decShiftToMost(res->lsu, res->digits, -adjust); 3925 res->exponent+=adjust; /* set the exponent. */ 3926 } 3927 #if DECSUBSET 3928 } /* extended */ 3929 #endif 3930 decFinish(res, set, &residue, status); /* clean and finalize */ 3931 break;} 3932 3933 /* [NB: both fastpath and mainpath code below assume these cases */ 3934 /* (notably 0-0) have already been handled] */ 3935 3936 /* calculate the padding needed to align the operands */ 3937 padding=rhs->exponent-lhs->exponent; 3938 3939 /* Fastpath cases where the numbers are aligned and normal, the RHS */ 3940 /* is all in one unit, no operand rounding is needed, and no carry, */ 3941 /* lengthening, or borrow is needed */ 3942 if (padding==0 3943 && rhs->digits<=DECDPUN 3944 && rhs->exponent>=set->emin /* [some normals drop through] */ 3945 && rhs->exponent<=set->emax-set->digits+1 /* [could clamp] */ 3946 && rhs->digits<=reqdigits 3947 && lhs->digits<=reqdigits) { 3948 Int partial=*lhs->lsu; 3949 if (!diffsign) { /* adding */ 3950 partial+=*rhs->lsu; 3951 if ((partial<=DECDPUNMAX) /* result fits in unit */ 3952 && (lhs->digits>=DECDPUN || /* .. and no digits-count change */ 3953 partial<(Int)powers[lhs->digits])) { /* .. */ 3954 if (res!=lhs) uprv_decNumberCopy(res, lhs); /* not in place */ 3955 *res->lsu=(Unit)partial; /* [copy could have overwritten RHS] */ 3956 break; 3957 } 3958 /* else drop out for careful add */ 3959 } 3960 else { /* signs differ */ 3961 partial-=*rhs->lsu; 3962 if (partial>0) { /* no borrow needed, and non-0 result */ 3963 if (res!=lhs) uprv_decNumberCopy(res, lhs); /* not in place */ 3964 *res->lsu=(Unit)partial; 3965 /* this could have reduced digits [but result>0] */ 3966 res->digits=decGetDigits(res->lsu, D2U(res->digits)); 3967 break; 3968 } 3969 /* else drop out for careful subtract */ 3970 } 3971 } 3972 3973 /* Now align (pad) the lhs or rhs so they can be added or */ 3974 /* subtracted, as necessary. If one number is much larger than */ 3975 /* the other (that is, if in plain form there is a least one */ 3976 /* digit between the lowest digit of one and the highest of the */ 3977 /* other) padding with up to DIGITS-1 trailing zeros may be */ 3978 /* needed; then apply rounding (as exotic rounding modes may be */ 3979 /* affected by the residue). */ 3980 rhsshift=0; /* rhs shift to left (padding) in Units */ 3981 bits=lhs->bits; /* assume sign is that of LHS */ 3982 mult=1; /* likely multiplier */ 3983 3984 /* [if padding==0 the operands are aligned; no padding is needed] */ 3985 if (padding!=0) { 3986 /* some padding needed; always pad the RHS, as any required */ 3987 /* padding can then be effected by a simple combination of */ 3988 /* shifts and a multiply */ 3989 Flag swapped=0; 3990 if (padding<0) { /* LHS needs the padding */ 3991 const decNumber *t; 3992 padding=-padding; /* will be +ve */ 3993 bits=(uByte)(rhs->bits^negate); /* assumed sign is now that of RHS */ 3994 t=lhs; lhs=rhs; rhs=t; 3995 swapped=1; 3996 } 3997 3998 /* If, after pad, rhs would be longer than lhs by digits+1 or */ 3999 /* more then lhs cannot affect the answer, except as a residue, */ 4000 /* so only need to pad up to a length of DIGITS+1. */ 4001 if (rhs->digits+padding > lhs->digits+reqdigits+1) { 4002 /* The RHS is sufficient */ 4003 /* for residue use the relative sign indication... */ 4004 Int shift=reqdigits-rhs->digits; /* left shift needed */ 4005 residue=1; /* residue for rounding */ 4006 if (diffsign) residue=-residue; /* signs differ */ 4007 /* copy, shortening if necessary */ 4008 decCopyFit(res, rhs, set, &residue, status); 4009 /* if it was already shorter, then need to pad with zeros */ 4010 if (shift>0) { 4011 res->digits=decShiftToMost(res->lsu, res->digits, shift); 4012 res->exponent-=shift; /* adjust the exponent. */ 4013 } 4014 /* flip the result sign if unswapped and rhs was negated */ 4015 if (!swapped) res->bits^=negate; 4016 decFinish(res, set, &residue, status); /* done */ 4017 break;} 4018 4019 /* LHS digits may affect result */ 4020 rhsshift=D2U(padding+1)-1; /* this much by Unit shift .. */ 4021 mult=powers[padding-(rhsshift*DECDPUN)]; /* .. this by multiplication */ 4022 } /* padding needed */ 4023 4024 if (diffsign) mult=-mult; /* signs differ */ 4025 4026 /* determine the longer operand */ 4027 maxdigits=rhs->digits+padding; /* virtual length of RHS */ 4028 if (lhs->digits>maxdigits) maxdigits=lhs->digits; 4029 4030 /* Decide on the result buffer to use; if possible place directly */ 4031 /* into result. */ 4032 acc=res->lsu; /* assume add direct to result */ 4033 /* If destructive overlap, or the number is too long, or a carry or */ 4034 /* borrow to DIGITS+1 might be possible, a buffer must be used. */ 4035 /* [Might be worth more sophisticated tests when maxdigits==reqdigits] */ 4036 if ((maxdigits>=reqdigits) /* is, or could be, too large */ 4037 || (res==rhs && rhsshift>0)) { /* destructive overlap */ 4038 /* buffer needed, choose it; units for maxdigits digits will be */ 4039 /* needed, +1 Unit for carry or borrow */ 4040 Int need=D2U(maxdigits)+1; 4041 acc=accbuff; /* assume use local buffer */ 4042 if (need*sizeof(Unit)>sizeof(accbuff)) { 4043 /* printf("malloc add %ld %ld\n", need, sizeof(accbuff)); */ 4044 allocacc=(Unit *)malloc(need*sizeof(Unit)); 4045 if (allocacc==NULL) { /* hopeless -- abandon */ 4046 *status|=DEC_Insufficient_storage; 4047 break;} 4048 acc=allocacc; 4049 } 4050 } 4051 4052 res->bits=(uByte)(bits&DECNEG); /* it's now safe to overwrite.. */ 4053 res->exponent=lhs->exponent; /* .. operands (even if aliased) */ 4054 4055 #if DECTRACE 4056 decDumpAr('A', lhs->lsu, D2U(lhs->digits)); 4057 decDumpAr('B', rhs->lsu, D2U(rhs->digits)); 4058 printf(" :h: %ld %ld\n", rhsshift, mult); 4059 #endif 4060 4061 /* add [A+B*m] or subtract [A+B*(-m)] */ 4062 res->digits=decUnitAddSub(lhs->lsu, D2U(lhs->digits), 4063 rhs->lsu, D2U(rhs->digits), 4064 rhsshift, acc, mult) 4065 *DECDPUN; /* [units -> digits] */ 4066 if (res->digits<0) { /* borrowed... */ 4067 res->digits=-res->digits; 4068 res->bits^=DECNEG; /* flip the sign */ 4069 } 4070 #if DECTRACE 4071 decDumpAr('+', acc, D2U(res->digits)); 4072 #endif 4073 4074 /* If a buffer was used the result must be copied back, possibly */ 4075 /* shortening. (If no buffer was used then the result must have */ 4076 /* fit, so can't need rounding and residue must be 0.) */ 4077 residue=0; /* clear accumulator */ 4078 if (acc!=res->lsu) { 4079 #if DECSUBSET 4080 if (set->extended) { /* round from first significant digit */ 4081 #endif 4082 /* remove leading zeros that were added due to rounding up to */ 4083 /* integral Units -- before the test for rounding. */ 4084 if (res->digits>reqdigits) 4085 res->digits=decGetDigits(acc, D2U(res->digits)); 4086 decSetCoeff(res, set, acc, res->digits, &residue, status); 4087 #if DECSUBSET 4088 } 4089 else { /* subset arithmetic rounds from original significant digit */ 4090 /* May have an underestimate. This only occurs when both */ 4091 /* numbers fit in DECDPUN digits and are padding with a */ 4092 /* negative multiple (-10, -100...) and the top digit(s) become */ 4093 /* 0. (This only matters when using X3.274 rules where the */ 4094 /* leading zero could be included in the rounding.) */ 4095 if (res->digits<maxdigits) { 4096 *(acc+D2U(res->digits))=0; /* ensure leading 0 is there */ 4097 res->digits=maxdigits; 4098 } 4099 else { 4100 /* remove leading zeros that added due to rounding up to */ 4101 /* integral Units (but only those in excess of the original */ 4102 /* maxdigits length, unless extended) before test for rounding. */ 4103 if (res->digits>reqdigits) { 4104 res->digits=decGetDigits(acc, D2U(res->digits)); 4105 if (res->digits<maxdigits) res->digits=maxdigits; 4106 } 4107 } 4108 decSetCoeff(res, set, acc, res->digits, &residue, status); 4109 /* Now apply rounding if needed before removing leading zeros. */ 4110 /* This is safe because subnormals are not a possibility */ 4111 if (residue!=0) { 4112 decApplyRound(res, set, residue, status); 4113 residue=0; /* did what needed to be done */ 4114 } 4115 } /* subset */ 4116 #endif 4117 } /* used buffer */ 4118 4119 /* strip leading zeros [these were left on in case of subset subtract] */ 4120 res->digits=decGetDigits(res->lsu, D2U(res->digits)); 4121 4122 /* apply checks and rounding */ 4123 decFinish(res, set, &residue, status); 4124 4125 /* "When the sum of two operands with opposite signs is exactly */ 4126 /* zero, the sign of that sum shall be '+' in all rounding modes */ 4127 /* except round toward -Infinity, in which mode that sign shall be */ 4128 /* '-'." [Subset zeros also never have '-', set by decFinish.] */ 4129 if (ISZERO(res) && diffsign 4130 #if DECSUBSET 4131 && set->extended 4132 #endif 4133 && (*status&DEC_Inexact)==0) { 4134 if (set->round==DEC_ROUND_FLOOR) res->bits|=DECNEG; /* sign - */ 4135 else res->bits&=~DECNEG; /* sign + */ 4136 } 4137 } while(0); /* end protected */ 4138 4139 if (allocacc!=NULL) free(allocacc); /* drop any storage used */ 4140 #if DECSUBSET 4141 if (allocrhs!=NULL) free(allocrhs); /* .. */ 4142 if (alloclhs!=NULL) free(alloclhs); /* .. */ 4143 #endif 4144 return res; 4145 } /* decAddOp */ 4146 4147 /* ------------------------------------------------------------------ */ 4148 /* decDivideOp -- division operation */ 4149 /* */ 4150 /* This routine performs the calculations for all four division */ 4151 /* operators (divide, divideInteger, remainder, remainderNear). */ 4152 /* */ 4153 /* C=A op B */ 4154 /* */ 4155 /* res is C, the result. C may be A and/or B (e.g., X=X/X) */ 4156 /* lhs is A */ 4157 /* rhs is B */ 4158 /* set is the context */ 4159 /* op is DIVIDE, DIVIDEINT, REMAINDER, or REMNEAR respectively. */ 4160 /* status is the usual accumulator */ 4161 /* */ 4162 /* C must have space for set->digits digits. */ 4163 /* */ 4164 /* ------------------------------------------------------------------ */ 4165 /* The underlying algorithm of this routine is the same as in the */ 4166 /* 1981 S/370 implementation, that is, non-restoring long division */ 4167 /* with bi-unit (rather than bi-digit) estimation for each unit */ 4168 /* multiplier. In this pseudocode overview, complications for the */ 4169 /* Remainder operators and division residues for exact rounding are */ 4170 /* omitted for clarity. */ 4171 /* */ 4172 /* Prepare operands and handle special values */ 4173 /* Test for x/0 and then 0/x */ 4174 /* Exp =Exp1 - Exp2 */ 4175 /* Exp =Exp +len(var1) -len(var2) */ 4176 /* Sign=Sign1 * Sign2 */ 4177 /* Pad accumulator (Var1) to double-length with 0's (pad1) */ 4178 /* Pad Var2 to same length as Var1 */ 4179 /* msu2pair/plus=1st 2 or 1 units of var2, +1 to allow for round */ 4180 /* have=0 */ 4181 /* Do until (have=digits+1 OR residue=0) */ 4182 /* if exp<0 then if integer divide/residue then leave */ 4183 /* this_unit=0 */ 4184 /* Do forever */ 4185 /* compare numbers */ 4186 /* if <0 then leave inner_loop */ 4187 /* if =0 then (* quick exit without subtract *) do */ 4188 /* this_unit=this_unit+1; output this_unit */ 4189 /* leave outer_loop; end */ 4190 /* Compare lengths of numbers (mantissae): */ 4191 /* If same then tops2=msu2pair -- {units 1&2 of var2} */ 4192 /* else tops2=msu2plus -- {0, unit 1 of var2} */ 4193 /* tops1=first_unit_of_Var1*10**DECDPUN +second_unit_of_var1 */ 4194 /* mult=tops1/tops2 -- Good and safe guess at divisor */ 4195 /* if mult=0 then mult=1 */ 4196 /* this_unit=this_unit+mult */ 4197 /* subtract */ 4198 /* end inner_loop */ 4199 /* if have\=0 | this_unit\=0 then do */ 4200 /* output this_unit */ 4201 /* have=have+1; end */ 4202 /* var2=var2/10 */ 4203 /* exp=exp-1 */ 4204 /* end outer_loop */ 4205 /* exp=exp+1 -- set the proper exponent */ 4206 /* if have=0 then generate answer=0 */ 4207 /* Return (Result is defined by Var1) */ 4208 /* */ 4209 /* ------------------------------------------------------------------ */ 4210 /* Two working buffers are needed during the division; one (digits+ */ 4211 /* 1) to accumulate the result, and the other (up to 2*digits+1) for */ 4212 /* long subtractions. These are acc and var1 respectively. */ 4213 /* var1 is a copy of the lhs coefficient, var2 is the rhs coefficient.*/ 4214 /* The static buffers may be larger than might be expected to allow */ 4215 /* for calls from higher-level funtions (notable exp). */ 4216 /* ------------------------------------------------------------------ */ 4217 static decNumber * decDivideOp(decNumber *res, 4218 const decNumber *lhs, const decNumber *rhs, 4219 decContext *set, Flag op, uInt *status) { 4220 #if DECSUBSET 4221 decNumber *alloclhs=NULL; /* non-NULL if rounded lhs allocated */ 4222 decNumber *allocrhs=NULL; /* .., rhs */ 4223 #endif 4224 Unit accbuff[SD2U(DECBUFFER+DECDPUN+10)]; /* local buffer */ 4225 Unit *acc=accbuff; /* -> accumulator array for result */ 4226 Unit *allocacc=NULL; /* -> allocated buffer, iff allocated */ 4227 Unit *accnext; /* -> where next digit will go */ 4228 Int acclength; /* length of acc needed [Units] */ 4229 Int accunits; /* count of units accumulated */ 4230 Int accdigits; /* count of digits accumulated */ 4231 4232 Unit varbuff[SD2U(DECBUFFER*2+DECDPUN)]; /* buffer for var1 */ 4233 Unit *var1=varbuff; /* -> var1 array for long subtraction */ 4234 Unit *varalloc=NULL; /* -> allocated buffer, iff used */ 4235 Unit *msu1; /* -> msu of var1 */ 4236 4237 const Unit *var2; /* -> var2 array */ 4238 const Unit *msu2; /* -> msu of var2 */ 4239 Int msu2plus; /* msu2 plus one [does not vary] */ 4240 eInt msu2pair; /* msu2 pair plus one [does not vary] */ 4241 4242 Int var1units, var2units; /* actual lengths */ 4243 Int var2ulen; /* logical length (units) */ 4244 Int var1initpad=0; /* var1 initial padding (digits) */ 4245 Int maxdigits; /* longest LHS or required acc length */ 4246 Int mult; /* multiplier for subtraction */ 4247 Unit thisunit; /* current unit being accumulated */ 4248 Int residue; /* for rounding */ 4249 Int reqdigits=set->digits; /* requested DIGITS */ 4250 Int exponent; /* working exponent */ 4251 Int maxexponent=0; /* DIVIDE maximum exponent if unrounded */ 4252 uByte bits; /* working sign */ 4253 Unit *target; /* work */ 4254 const Unit *source; /* .. */ 4255 uInt const *pow; /* .. */ 4256 Int shift, cut; /* .. */ 4257 #if DECSUBSET 4258 Int dropped; /* work */ 4259 #endif 4260 4261 #if DECCHECK 4262 if (decCheckOperands(res, lhs, rhs, set)) return res; 4263 #endif 4264 4265 do { /* protect allocated storage */ 4266 #if DECSUBSET 4267 if (!set->extended) { 4268 /* reduce operands and set lostDigits status, as needed */ 4269 if (lhs->digits>reqdigits) { 4270 alloclhs=decRoundOperand(lhs, set, status); 4271 if (alloclhs==NULL) break; 4272 lhs=alloclhs; 4273 } 4274 if (rhs->digits>reqdigits) { 4275 allocrhs=decRoundOperand(rhs, set, status); 4276 if (allocrhs==NULL) break; 4277 rhs=allocrhs; 4278 } 4279 } 4280 #endif 4281 /* [following code does not require input rounding] */ 4282 4283 bits=(lhs->bits^rhs->bits)&DECNEG; /* assumed sign for divisions */ 4284 4285 /* handle infinities and NaNs */ 4286 if (SPECIALARGS) { /* a special bit set */ 4287 if (SPECIALARGS & (DECSNAN | DECNAN)) { /* one or two NaNs */ 4288 decNaNs(res, lhs, rhs, set, status); 4289 break; 4290 } 4291 /* one or two infinities */ 4292 if (decNumberIsInfinite(lhs)) { /* LHS (dividend) is infinite */ 4293 if (decNumberIsInfinite(rhs) || /* two infinities are invalid .. */ 4294 op & (REMAINDER | REMNEAR)) { /* as is remainder of infinity */ 4295 *status|=DEC_Invalid_operation; 4296 break; 4297 } 4298 /* [Note that infinity/0 raises no exceptions] */ 4299 uprv_decNumberZero(res); 4300 res->bits=bits|DECINF; /* set +/- infinity */ 4301 break; 4302 } 4303 else { /* RHS (divisor) is infinite */ 4304 residue=0; 4305 if (op&(REMAINDER|REMNEAR)) { 4306 /* result is [finished clone of] lhs */ 4307 decCopyFit(res, lhs, set, &residue, status); 4308 } 4309 else { /* a division */ 4310 uprv_decNumberZero(res); 4311 res->bits=bits; /* set +/- zero */ 4312 /* for DIVIDEINT the exponent is always 0. For DIVIDE, result */ 4313 /* is a 0 with infinitely negative exponent, clamped to minimum */ 4314 if (op&DIVIDE) { 4315 res->exponent=set->emin-set->digits+1; 4316 *status|=DEC_Clamped; 4317 } 4318 } 4319 decFinish(res, set, &residue, status); 4320 break; 4321 } 4322 } 4323 4324 /* handle 0 rhs (x/0) */ 4325 if (ISZERO(rhs)) { /* x/0 is always exceptional */ 4326 if (ISZERO(lhs)) { 4327 uprv_decNumberZero(res); /* [after lhs test] */ 4328 *status|=DEC_Division_undefined;/* 0/0 will become NaN */ 4329 } 4330 else { 4331 uprv_decNumberZero(res); 4332 if (op&(REMAINDER|REMNEAR)) *status|=DEC_Invalid_operation; 4333 else { 4334 *status|=DEC_Division_by_zero; /* x/0 */ 4335 res->bits=bits|DECINF; /* .. is +/- Infinity */ 4336 } 4337 } 4338 break;} 4339 4340 /* handle 0 lhs (0/x) */ 4341 if (ISZERO(lhs)) { /* 0/x [x!=0] */ 4342 #if DECSUBSET 4343 if (!set->extended) uprv_decNumberZero(res); 4344 else { 4345 #endif 4346 if (op&DIVIDE) { 4347 residue=0; 4348 exponent=lhs->exponent-rhs->exponent; /* ideal exponent */ 4349 uprv_decNumberCopy(res, lhs); /* [zeros always fit] */ 4350 res->bits=bits; /* sign as computed */ 4351 res->exponent=exponent; /* exponent, too */ 4352 decFinalize(res, set, &residue, status); /* check exponent */ 4353 } 4354 else if (op&DIVIDEINT) { 4355 uprv_decNumberZero(res); /* integer 0 */ 4356 res->bits=bits; /* sign as computed */ 4357 } 4358 else { /* a remainder */ 4359 exponent=rhs->exponent; /* [save in case overwrite] */ 4360 uprv_decNumberCopy(res, lhs); /* [zeros always fit] */ 4361 if (exponent<res->exponent) res->exponent=exponent; /* use lower */ 4362 } 4363 #if DECSUBSET 4364 } 4365 #endif 4366 break;} 4367 4368 /* Precalculate exponent. This starts off adjusted (and hence fits */ 4369 /* in 31 bits) and becomes the usual unadjusted exponent as the */ 4370 /* division proceeds. The order of evaluation is important, here, */ 4371 /* to avoid wrap. */ 4372 exponent=(lhs->exponent+lhs->digits)-(rhs->exponent+rhs->digits); 4373 4374 /* If the working exponent is -ve, then some quick exits are */ 4375 /* possible because the quotient is known to be <1 */ 4376 /* [for REMNEAR, it needs to be < -1, as -0.5 could need work] */ 4377 if (exponent<0 && !(op==DIVIDE)) { 4378 if (op&DIVIDEINT) { 4379 uprv_decNumberZero(res); /* integer part is 0 */ 4380 #if DECSUBSET 4381 if (set->extended) 4382 #endif 4383 res->bits=bits; /* set +/- zero */ 4384 break;} 4385 /* fastpath remainders so long as the lhs has the smaller */ 4386 /* (or equal) exponent */ 4387 if (lhs->exponent<=rhs->exponent) { 4388 if (op&REMAINDER || exponent<-1) { 4389 /* It is REMAINDER or safe REMNEAR; result is [finished */ 4390 /* clone of] lhs (r = x - 0*y) */ 4391 residue=0; 4392 decCopyFit(res, lhs, set, &residue, status); 4393 decFinish(res, set, &residue, status); 4394 break; 4395 } 4396 /* [unsafe REMNEAR drops through] */ 4397 } 4398 } /* fastpaths */ 4399 4400 /* Long (slow) division is needed; roll up the sleeves... */ 4401 4402 /* The accumulator will hold the quotient of the division. */ 4403 /* If it needs to be too long for stack storage, then allocate. */ 4404 acclength=D2U(reqdigits+DECDPUN); /* in Units */ 4405 if (acclength*sizeof(Unit)>sizeof(accbuff)) { 4406 /* printf("malloc dvacc %ld units\n", acclength); */ 4407 allocacc=(Unit *)malloc(acclength*sizeof(Unit)); 4408 if (allocacc==NULL) { /* hopeless -- abandon */ 4409 *status|=DEC_Insufficient_storage; 4410 break;} 4411 acc=allocacc; /* use the allocated space */ 4412 } 4413 4414 /* var1 is the padded LHS ready for subtractions. */ 4415 /* If it needs to be too long for stack storage, then allocate. */ 4416 /* The maximum units needed for var1 (long subtraction) is: */ 4417 /* Enough for */ 4418 /* (rhs->digits+reqdigits-1) -- to allow full slide to right */ 4419 /* or (lhs->digits) -- to allow for long lhs */ 4420 /* whichever is larger */ 4421 /* +1 -- for rounding of slide to right */ 4422 /* +1 -- for leading 0s */ 4423 /* +1 -- for pre-adjust if a remainder or DIVIDEINT */ 4424 /* [Note: unused units do not participate in decUnitAddSub data] */ 4425 maxdigits=rhs->digits+reqdigits-1; 4426 if (lhs->digits>maxdigits) maxdigits=lhs->digits; 4427 var1units=D2U(maxdigits)+2; 4428 /* allocate a guard unit above msu1 for REMAINDERNEAR */ 4429 if (!(op&DIVIDE)) var1units++; 4430 if ((var1units+1)*sizeof(Unit)>sizeof(varbuff)) { 4431 /* printf("malloc dvvar %ld units\n", var1units+1); */ 4432 varalloc=(Unit *)malloc((var1units+1)*sizeof(Unit)); 4433 if (varalloc==NULL) { /* hopeless -- abandon */ 4434 *status|=DEC_Insufficient_storage; 4435 break;} 4436 var1=varalloc; /* use the allocated space */ 4437 } 4438 4439 /* Extend the lhs and rhs to full long subtraction length. The lhs */ 4440 /* is truly extended into the var1 buffer, with 0 padding, so a */ 4441 /* subtract in place is always possible. The rhs (var2) has */ 4442 /* virtual padding (implemented by decUnitAddSub). */ 4443 /* One guard unit was allocated above msu1 for rem=rem+rem in */ 4444 /* REMAINDERNEAR. */ 4445 msu1=var1+var1units-1; /* msu of var1 */ 4446 source=lhs->lsu+D2U(lhs->digits)-1; /* msu of input array */ 4447 for (target=msu1; source>=lhs->lsu; source--, target--) *target=*source; 4448 for (; target>=var1; target--) *target=0; 4449 4450 /* rhs (var2) is left-aligned with var1 at the start */ 4451 var2ulen=var1units; /* rhs logical length (units) */ 4452 var2units=D2U(rhs->digits); /* rhs actual length (units) */ 4453 var2=rhs->lsu; /* -> rhs array */ 4454 msu2=var2+var2units-1; /* -> msu of var2 [never changes] */ 4455 /* now set up the variables which will be used for estimating the */ 4456 /* multiplication factor. If these variables are not exact, add */ 4457 /* 1 to make sure that the multiplier is never overestimated. */ 4458 msu2plus=*msu2; /* it's value .. */ 4459 if (var2units>1) msu2plus++; /* .. +1 if any more */ 4460 msu2pair=(eInt)*msu2*(DECDPUNMAX+1);/* top two pair .. */ 4461 if (var2units>1) { /* .. [else treat 2nd as 0] */ 4462 msu2pair+=*(msu2-1); /* .. */ 4463 if (var2units>2) msu2pair++; /* .. +1 if any more */ 4464 } 4465 4466 /* The calculation is working in units, which may have leading zeros, */ 4467 /* but the exponent was calculated on the assumption that they are */ 4468 /* both left-aligned. Adjust the exponent to compensate: add the */ 4469 /* number of leading zeros in var1 msu and subtract those in var2 msu. */ 4470 /* [This is actually done by counting the digits and negating, as */ 4471 /* lead1=DECDPUN-digits1, and similarly for lead2.] */ 4472 for (pow=&powers[1]; *msu1>=*pow; pow++) exponent--; 4473 for (pow=&powers[1]; *msu2>=*pow; pow++) exponent++; 4474 4475 /* Now, if doing an integer divide or remainder, ensure that */ 4476 /* the result will be Unit-aligned. To do this, shift the var1 */ 4477 /* accumulator towards least if need be. (It's much easier to */ 4478 /* do this now than to reassemble the residue afterwards, if */ 4479 /* doing a remainder.) Also ensure the exponent is not negative. */ 4480 if (!(op&DIVIDE)) { 4481 Unit *u; /* work */ 4482 /* save the initial 'false' padding of var1, in digits */ 4483 var1initpad=(var1units-D2U(lhs->digits))*DECDPUN; 4484 /* Determine the shift to do. */ 4485 if (exponent<0) cut=-exponent; 4486 else cut=DECDPUN-exponent%DECDPUN; 4487 decShiftToLeast(var1, var1units, cut); 4488 exponent+=cut; /* maintain numerical value */ 4489 var1initpad-=cut; /* .. and reduce padding */ 4490 /* clean any most-significant units which were just emptied */ 4491 for (u=msu1; cut>=DECDPUN; cut-=DECDPUN, u--) *u=0; 4492 } /* align */ 4493 else { /* is DIVIDE */ 4494 maxexponent=lhs->exponent-rhs->exponent; /* save */ 4495 /* optimization: if the first iteration will just produce 0, */ 4496 /* preadjust to skip it [valid for DIVIDE only] */ 4497 if (*msu1<*msu2) { 4498 var2ulen--; /* shift down */ 4499 exponent-=DECDPUN; /* update the exponent */ 4500 } 4501 } 4502 4503 /* ---- start the long-division loops ------------------------------ */ 4504 accunits=0; /* no units accumulated yet */ 4505 accdigits=0; /* .. or digits */ 4506 accnext=acc+acclength-1; /* -> msu of acc [NB: allows digits+1] */ 4507 for (;;) { /* outer forever loop */ 4508 thisunit=0; /* current unit assumed 0 */ 4509 /* find the next unit */ 4510 for (;;) { /* inner forever loop */ 4511 /* strip leading zero units [from either pre-adjust or from */ 4512 /* subtract last time around]. Leave at least one unit. */ 4513 for (; *msu1==0 && msu1>var1; msu1--) var1units--; 4514 4515 if (var1units<var2ulen) break; /* var1 too low for subtract */ 4516 if (var1units==var2ulen) { /* unit-by-unit compare needed */ 4517 /* compare the two numbers, from msu */ 4518 const Unit *pv1, *pv2; 4519 Unit v2; /* units to compare */ 4520 pv2=msu2; /* -> msu */ 4521 for (pv1=msu1; ; pv1--, pv2--) { 4522 /* v1=*pv1 -- always OK */ 4523 v2=0; /* assume in padding */ 4524 if (pv2>=var2) v2=*pv2; /* in range */ 4525 if (*pv1!=v2) break; /* no longer the same */ 4526 if (pv1==var1) break; /* done; leave pv1 as is */ 4527 } 4528 /* here when all inspected or a difference seen */ 4529 if (*pv1<v2) break; /* var1 too low to subtract */ 4530 if (*pv1==v2) { /* var1 == var2 */ 4531 /* reach here if var1 and var2 are identical; subtraction */ 4532 /* would increase digit by one, and the residue will be 0 so */ 4533 /* the calculation is done; leave the loop with residue=0. */ 4534 thisunit++; /* as though subtracted */ 4535 *var1=0; /* set var1 to 0 */ 4536 var1units=1; /* .. */ 4537 break; /* from inner */ 4538 } /* var1 == var2 */ 4539 /* *pv1>v2. Prepare for real subtraction; the lengths are equal */ 4540 /* Estimate the multiplier (there's always a msu1-1)... */ 4541 /* Bring in two units of var2 to provide a good estimate. */ 4542 mult=(Int)(((eInt)*msu1*(DECDPUNMAX+1)+*(msu1-1))/msu2pair); 4543 } /* lengths the same */ 4544 else { /* var1units > var2ulen, so subtraction is safe */ 4545 /* The var2 msu is one unit towards the lsu of the var1 msu, */ 4546 /* so only one unit for var2 can be used. */ 4547 mult=(Int)(((eInt)*msu1*(DECDPUNMAX+1)+*(msu1-1))/msu2plus); 4548 } 4549 if (mult==0) mult=1; /* must always be at least 1 */ 4550 /* subtraction needed; var1 is > var2 */ 4551 thisunit=(Unit)(thisunit+mult); /* accumulate */ 4552 /* subtract var1-var2, into var1; only the overlap needs */ 4553 /* processing, as this is an in-place calculation */ 4554 shift=var2ulen-var2units; 4555 #if DECTRACE 4556 decDumpAr('1', &var1[shift], var1units-shift); 4557 decDumpAr('2', var2, var2units); 4558 printf("m=%ld\n", -mult); 4559 #endif 4560 decUnitAddSub(&var1[shift], var1units-shift, 4561 var2, var2units, 0, 4562 &var1[shift], -mult); 4563 #if DECTRACE 4564 decDumpAr('#', &var1[shift], var1units-shift); 4565 #endif 4566 /* var1 now probably has leading zeros; these are removed at the */ 4567 /* top of the inner loop. */ 4568 } /* inner loop */ 4569 4570 /* The next unit has been calculated in full; unless it's a */ 4571 /* leading zero, add to acc */ 4572 if (accunits!=0 || thisunit!=0) { /* is first or non-zero */ 4573 *accnext=thisunit; /* store in accumulator */ 4574 /* account exactly for the new digits */ 4575 if (accunits==0) { 4576 accdigits++; /* at least one */ 4577 for (pow=&powers[1]; thisunit>=*pow; pow++) accdigits++; 4578 } 4579 else accdigits+=DECDPUN; 4580 accunits++; /* update count */ 4581 accnext--; /* ready for next */ 4582 if (accdigits>reqdigits) break; /* have enough digits */ 4583 } 4584 4585 /* if the residue is zero, the operation is done (unless divide */ 4586 /* or divideInteger and still not enough digits yet) */ 4587 if (*var1==0 && var1units==1) { /* residue is 0 */ 4588 if (op&(REMAINDER|REMNEAR)) break; 4589 if ((op&DIVIDE) && (exponent<=maxexponent)) break; 4590 /* [drop through if divideInteger] */ 4591 } 4592 /* also done enough if calculating remainder or integer */ 4593 /* divide and just did the last ('units') unit */ 4594 if (exponent==0 && !(op&DIVIDE)) break; 4595 4596 /* to get here, var1 is less than var2, so divide var2 by the per- */ 4597 /* Unit power of ten and go for the next digit */ 4598 var2ulen--; /* shift down */ 4599 exponent-=DECDPUN; /* update the exponent */ 4600 } /* outer loop */ 4601 4602 /* ---- division is complete --------------------------------------- */ 4603 /* here: acc has at least reqdigits+1 of good results (or fewer */ 4604 /* if early stop), starting at accnext+1 (its lsu) */ 4605 /* var1 has any residue at the stopping point */ 4606 /* accunits is the number of digits collected in acc */ 4607 if (accunits==0) { /* acc is 0 */ 4608 accunits=1; /* show have a unit .. */ 4609 accdigits=1; /* .. */ 4610 *accnext=0; /* .. whose value is 0 */ 4611 } 4612 else accnext++; /* back to last placed */ 4613 /* accnext now -> lowest unit of result */ 4614 4615 residue=0; /* assume no residue */ 4616 if (op&DIVIDE) { 4617 /* record the presence of any residue, for rounding */ 4618 if (*var1!=0 || var1units>1) residue=1; 4619 else { /* no residue */ 4620 /* Had an exact division; clean up spurious trailing 0s. */ 4621 /* There will be at most DECDPUN-1, from the final multiply, */ 4622 /* and then only if the result is non-0 (and even) and the */ 4623 /* exponent is 'loose'. */ 4624 #if DECDPUN>1 4625 Unit lsu=*accnext; 4626 if (!(lsu&0x01) && (lsu!=0)) { 4627 /* count the trailing zeros */ 4628 Int drop=0; 4629 for (;; drop++) { /* [will terminate because lsu!=0] */ 4630 if (exponent>=maxexponent) break; /* don't chop real 0s */ 4631 #if DECDPUN<=4 4632 if ((lsu-QUOT10(lsu, drop+1) 4633 *powers[drop+1])!=0) break; /* found non-0 digit */ 4634 #else 4635 if (lsu%powers[drop+1]!=0) break; /* found non-0 digit */ 4636 #endif 4637 exponent++; 4638 } 4639 if (drop>0) { 4640 accunits=decShiftToLeast(accnext, accunits, drop); 4641 accdigits=decGetDigits(accnext, accunits); 4642 accunits=D2U(accdigits); 4643 /* [exponent was adjusted in the loop] */ 4644 } 4645 } /* neither odd nor 0 */ 4646 #endif 4647 } /* exact divide */ 4648 } /* divide */ 4649 else /* op!=DIVIDE */ { 4650 /* check for coefficient overflow */ 4651 if (accdigits+exponent>reqdigits) { 4652 *status|=DEC_Division_impossible; 4653 break; 4654 } 4655 if (op & (REMAINDER|REMNEAR)) { 4656 /* [Here, the exponent will be 0, because var1 was adjusted */ 4657 /* appropriately.] */ 4658 Int postshift; /* work */ 4659 Flag wasodd=0; /* integer was odd */ 4660 Unit *quotlsu; /* for save */ 4661 Int quotdigits; /* .. */ 4662 4663 bits=lhs->bits; /* remainder sign is always as lhs */ 4664 4665 /* Fastpath when residue is truly 0 is worthwhile [and */ 4666 /* simplifies the code below] */ 4667 if (*var1==0 && var1units==1) { /* residue is 0 */ 4668 Int exp=lhs->exponent; /* save min(exponents) */ 4669 if (rhs->exponent<exp) exp=rhs->exponent; 4670 uprv_decNumberZero(res); /* 0 coefficient */ 4671 #if DECSUBSET 4672 if (set->extended) 4673 #endif 4674 res->exponent=exp; /* .. with proper exponent */ 4675 res->bits=(uByte)(bits&DECNEG); /* [cleaned] */ 4676 decFinish(res, set, &residue, status); /* might clamp */ 4677 break; 4678 } 4679 /* note if the quotient was odd */ 4680 if (*accnext & 0x01) wasodd=1; /* acc is odd */ 4681 quotlsu=accnext; /* save in case need to reinspect */ 4682 quotdigits=accdigits; /* .. */ 4683 4684 /* treat the residue, in var1, as the value to return, via acc */ 4685 /* calculate the unused zero digits. This is the smaller of: */ 4686 /* var1 initial padding (saved above) */ 4687 /* var2 residual padding, which happens to be given by: */ 4688 postshift=var1initpad+exponent-lhs->exponent+rhs->exponent; 4689 /* [the 'exponent' term accounts for the shifts during divide] */ 4690 if (var1initpad<postshift) postshift=var1initpad; 4691 4692 /* shift var1 the requested amount, and adjust its digits */ 4693 var1units=decShiftToLeast(var1, var1units, postshift); 4694 accnext=var1; 4695 accdigits=decGetDigits(var1, var1units); 4696 accunits=D2U(accdigits); 4697 4698 exponent=lhs->exponent; /* exponent is smaller of lhs & rhs */ 4699 if (rhs->exponent<exponent) exponent=rhs->exponent; 4700 4701 /* Now correct the result if doing remainderNear; if it */ 4702 /* (looking just at coefficients) is > rhs/2, or == rhs/2 and */ 4703 /* the integer was odd then the result should be rem-rhs. */ 4704 if (op&REMNEAR) { 4705 Int compare, tarunits; /* work */ 4706 Unit *up; /* .. */ 4707 /* calculate remainder*2 into the var1 buffer (which has */ 4708 /* 'headroom' of an extra unit and hence enough space) */ 4709 /* [a dedicated 'double' loop would be faster, here] */ 4710 tarunits=decUnitAddSub(accnext, accunits, accnext, accunits, 4711 0, accnext, 1); 4712 /* decDumpAr('r', accnext, tarunits); */ 4713 4714 /* Here, accnext (var1) holds tarunits Units with twice the */ 4715 /* remainder's coefficient, which must now be compared to the */ 4716 /* RHS. The remainder's exponent may be smaller than the RHS's. */ 4717 compare=decUnitCompare(accnext, tarunits, rhs->lsu, D2U(rhs->digits), 4718 rhs->exponent-exponent); 4719 if (compare==BADINT) { /* deep trouble */ 4720 *status|=DEC_Insufficient_storage; 4721 break;} 4722 4723 /* now restore the remainder by dividing by two; the lsu */ 4724 /* is known to be even. */ 4725 for (up=accnext; up<accnext+tarunits; up++) { 4726 Int half; /* half to add to lower unit */ 4727 half=*up & 0x01; 4728 *up/=2; /* [shift] */ 4729 if (!half) continue; 4730 *(up-1)+=(DECDPUNMAX+1)/2; 4731 } 4732 /* [accunits still describes the original remainder length] */ 4733 4734 if (compare>0 || (compare==0 && wasodd)) { /* adjustment needed */ 4735 Int exp, expunits, exprem; /* work */ 4736 /* This is effectively causing round-up of the quotient, */ 4737 /* so if it was the rare case where it was full and all */ 4738 /* nines, it would overflow and hence division-impossible */ 4739 /* should be raised */ 4740 Flag allnines=0; /* 1 if quotient all nines */ 4741 if (quotdigits==reqdigits) { /* could be borderline */ 4742 for (up=quotlsu; ; up++) { 4743 if (quotdigits>DECDPUN) { 4744 if (*up!=DECDPUNMAX) break;/* non-nines */ 4745 } 4746 else { /* this is the last Unit */ 4747 if (*up==powers[quotdigits]-1) allnines=1; 4748 break; 4749 } 4750 quotdigits-=DECDPUN; /* checked those digits */ 4751 } /* up */ 4752 } /* borderline check */ 4753 if (allnines) { 4754 *status|=DEC_Division_impossible; 4755 break;} 4756 4757 /* rem-rhs is needed; the sign will invert. Again, var1 */ 4758 /* can safely be used for the working Units array. */ 4759 exp=rhs->exponent-exponent; /* RHS padding needed */ 4760 /* Calculate units and remainder from exponent. */ 4761 expunits=exp/DECDPUN; 4762 exprem=exp%DECDPUN; 4763 /* subtract [A+B*(-m)]; the result will always be negative */ 4764 accunits=-decUnitAddSub(accnext, accunits, 4765 rhs->lsu, D2U(rhs->digits), 4766 expunits, accnext, -(Int)powers[exprem]); 4767 accdigits=decGetDigits(accnext, accunits); /* count digits exactly */ 4768 accunits=D2U(accdigits); /* and recalculate the units for copy */ 4769 /* [exponent is as for original remainder] */ 4770 bits^=DECNEG; /* flip the sign */ 4771 } 4772 } /* REMNEAR */ 4773 } /* REMAINDER or REMNEAR */ 4774 } /* not DIVIDE */ 4775 4776 /* Set exponent and bits */ 4777 res->exponent=exponent; 4778 res->bits=(uByte)(bits&DECNEG); /* [cleaned] */ 4779 4780 /* Now the coefficient. */ 4781 decSetCoeff(res, set, accnext, accdigits, &residue, status); 4782 4783 decFinish(res, set, &residue, status); /* final cleanup */ 4784 4785 #if DECSUBSET 4786 /* If a divide then strip trailing zeros if subset [after round] */ 4787 if (!set->extended && (op==DIVIDE)) decTrim(res, set, 0, 1, &dropped); 4788 #endif 4789 } while(0); /* end protected */ 4790 4791 if (varalloc!=NULL) free(varalloc); /* drop any storage used */ 4792 if (allocacc!=NULL) free(allocacc); /* .. */ 4793 #if DECSUBSET 4794 if (allocrhs!=NULL) free(allocrhs); /* .. */ 4795 if (alloclhs!=NULL) free(alloclhs); /* .. */ 4796 #endif 4797 return res; 4798 } /* decDivideOp */ 4799 4800 /* ------------------------------------------------------------------ */ 4801 /* decMultiplyOp -- multiplication operation */ 4802 /* */ 4803 /* This routine performs the multiplication C=A x B. */ 4804 /* */ 4805 /* res is C, the result. C may be A and/or B (e.g., X=X*X) */ 4806 /* lhs is A */ 4807 /* rhs is B */ 4808 /* set is the context */ 4809 /* status is the usual accumulator */ 4810 /* */ 4811 /* C must have space for set->digits digits. */ 4812 /* */ 4813 /* ------------------------------------------------------------------ */ 4814 /* 'Classic' multiplication is used rather than Karatsuba, as the */ 4815 /* latter would give only a minor improvement for the short numbers */ 4816 /* expected to be handled most (and uses much more memory). */ 4817 /* */ 4818 /* There are two major paths here: the general-purpose ('old code') */ 4819 /* path which handles all DECDPUN values, and a fastpath version */ 4820 /* which is used if 64-bit ints are available, DECDPUN<=4, and more */ 4821 /* than two calls to decUnitAddSub would be made. */ 4822 /* */ 4823 /* The fastpath version lumps units together into 8-digit or 9-digit */ 4824 /* chunks, and also uses a lazy carry strategy to minimise expensive */ 4825 /* 64-bit divisions. The chunks are then broken apart again into */ 4826 /* units for continuing processing. Despite this overhead, the */ 4827 /* fastpath can speed up some 16-digit operations by 10x (and much */ 4828 /* more for higher-precision calculations). */ 4829 /* */ 4830 /* A buffer always has to be used for the accumulator; in the */ 4831 /* fastpath, buffers are also always needed for the chunked copies of */ 4832 /* of the operand coefficients. */ 4833 /* Static buffers are larger than needed just for multiply, to allow */ 4834 /* for calls from other operations (notably exp). */ 4835 /* ------------------------------------------------------------------ */ 4836 #define FASTMUL (DECUSE64 && DECDPUN<5) 4837 static decNumber * decMultiplyOp(decNumber *res, const decNumber *lhs, 4838 const decNumber *rhs, decContext *set, 4839 uInt *status) { 4840 Int accunits; /* Units of accumulator in use */ 4841 Int exponent; /* work */ 4842 Int residue=0; /* rounding residue */ 4843 uByte bits; /* result sign */ 4844 Unit *acc; /* -> accumulator Unit array */ 4845 Int needbytes; /* size calculator */ 4846 void *allocacc=NULL; /* -> allocated accumulator, iff allocated */ 4847 Unit accbuff[SD2U(DECBUFFER*4+1)]; /* buffer (+1 for DECBUFFER==0, */ 4848 /* *4 for calls from other operations) */ 4849 const Unit *mer, *mermsup; /* work */ 4850 Int madlength; /* Units in multiplicand */ 4851 Int shift; /* Units to shift multiplicand by */ 4852 4853 #if FASTMUL 4854 /* if DECDPUN is 1 or 3 work in base 10**9, otherwise */ 4855 /* (DECDPUN is 2 or 4) then work in base 10**8 */ 4856 #if DECDPUN & 1 /* odd */ 4857 #define FASTBASE 1000000000 /* base */ 4858 #define FASTDIGS 9 /* digits in base */ 4859 #define FASTLAZY 18 /* carry resolution point [1->18] */ 4860 #else 4861 #define FASTBASE 100000000 4862 #define FASTDIGS 8 4863 #define FASTLAZY 1844 /* carry resolution point [1->1844] */ 4864 #endif 4865 /* three buffers are used, two for chunked copies of the operands */ 4866 /* (base 10**8 or base 10**9) and one base 2**64 accumulator with */ 4867 /* lazy carry evaluation */ 4868 uInt zlhibuff[(DECBUFFER*2+1)/8+1]; /* buffer (+1 for DECBUFFER==0) */ 4869 uInt *zlhi=zlhibuff; /* -> lhs array */ 4870 uInt *alloclhi=NULL; /* -> allocated buffer, iff allocated */ 4871 uInt zrhibuff[(DECBUFFER*2+1)/8+1]; /* buffer (+1 for DECBUFFER==0) */ 4872 uInt *zrhi=zrhibuff; /* -> rhs array */ 4873 uInt *allocrhi=NULL; /* -> allocated buffer, iff allocated */ 4874 uLong zaccbuff[(DECBUFFER*2+1)/4+2]; /* buffer (+1 for DECBUFFER==0) */ 4875 /* [allocacc is shared for both paths, as only one will run] */ 4876 uLong *zacc=zaccbuff; /* -> accumulator array for exact result */ 4877 #if DECDPUN==1 4878 Int zoff; /* accumulator offset */ 4879 #endif 4880 uInt *lip, *rip; /* item pointers */ 4881 uInt *lmsi, *rmsi; /* most significant items */ 4882 Int ilhs, irhs, iacc; /* item counts in the arrays */ 4883 Int lazy; /* lazy carry counter */ 4884 uLong lcarry; /* uLong carry */ 4885 uInt carry; /* carry (NB not uLong) */ 4886 Int count; /* work */ 4887 const Unit *cup; /* .. */ 4888 Unit *up; /* .. */ 4889 uLong *lp; /* .. */ 4890 Int p; /* .. */ 4891 #endif 4892 4893 #if DECSUBSET 4894 decNumber *alloclhs=NULL; /* -> allocated buffer, iff allocated */ 4895 decNumber *allocrhs=NULL; /* -> allocated buffer, iff allocated */ 4896 #endif 4897 4898 #if DECCHECK 4899 if (decCheckOperands(res, lhs, rhs, set)) return res; 4900 #endif 4901 4902 /* precalculate result sign */ 4903 bits=(uByte)((lhs->bits^rhs->bits)&DECNEG); 4904 4905 /* handle infinities and NaNs */ 4906 if (SPECIALARGS) { /* a special bit set */ 4907 if (SPECIALARGS & (DECSNAN | DECNAN)) { /* one or two NaNs */ 4908 decNaNs(res, lhs, rhs, set, status); 4909 return res;} 4910 /* one or two infinities; Infinity * 0 is invalid */ 4911 if (((lhs->bits & DECINF)==0 && ISZERO(lhs)) 4912 ||((rhs->bits & DECINF)==0 && ISZERO(rhs))) { 4913 *status|=DEC_Invalid_operation; 4914 return res;} 4915 uprv_decNumberZero(res); 4916 res->bits=bits|DECINF; /* infinity */ 4917 return res;} 4918 4919 /* For best speed, as in DMSRCN [the original Rexx numerics */ 4920 /* module], use the shorter number as the multiplier (rhs) and */ 4921 /* the longer as the multiplicand (lhs) to minimise the number of */ 4922 /* adds (partial products) */ 4923 if (lhs->digits<rhs->digits) { /* swap... */ 4924 const decNumber *hold=lhs; 4925 lhs=rhs; 4926 rhs=hold; 4927 } 4928 4929 do { /* protect allocated storage */ 4930 #if DECSUBSET 4931 if (!set->extended) { 4932 /* reduce operands and set lostDigits status, as needed */ 4933 if (lhs->digits>set->digits) { 4934 alloclhs=decRoundOperand(lhs, set, status); 4935 if (alloclhs==NULL) break; 4936 lhs=alloclhs; 4937 } 4938 if (rhs->digits>set->digits) { 4939 allocrhs=decRoundOperand(rhs, set, status); 4940 if (allocrhs==NULL) break; 4941 rhs=allocrhs; 4942 } 4943 } 4944 #endif 4945 /* [following code does not require input rounding] */ 4946 4947 #if FASTMUL /* fastpath can be used */ 4948 /* use the fast path if there are enough digits in the shorter */ 4949 /* operand to make the setup and takedown worthwhile */ 4950 #define NEEDTWO (DECDPUN*2) /* within two decUnitAddSub calls */ 4951 if (rhs->digits>NEEDTWO) { /* use fastpath... */ 4952 /* calculate the number of elements in each array */ 4953 ilhs=(lhs->digits+FASTDIGS-1)/FASTDIGS; /* [ceiling] */ 4954 irhs=(rhs->digits+FASTDIGS-1)/FASTDIGS; /* .. */ 4955 iacc=ilhs+irhs; 4956 4957 /* allocate buffers if required, as usual */ 4958 needbytes=ilhs*sizeof(uInt); 4959 if (needbytes>(Int)sizeof(zlhibuff)) { 4960 alloclhi=(uInt *)malloc(needbytes); 4961 zlhi=alloclhi;} 4962 needbytes=irhs*sizeof(uInt); 4963 if (needbytes>(Int)sizeof(zrhibuff)) { 4964 allocrhi=(uInt *)malloc(needbytes); 4965 zrhi=allocrhi;} 4966 4967 /* Allocating the accumulator space needs a special case when */ 4968 /* DECDPUN=1 because when converting the accumulator to Units */ 4969 /* after the multiplication each 8-byte item becomes 9 1-byte */ 4970 /* units. Therefore iacc extra bytes are needed at the front */ 4971 /* (rounded up to a multiple of 8 bytes), and the uLong */ 4972 /* accumulator starts offset the appropriate number of units */ 4973 /* to the right to avoid overwrite during the unchunking. */ 4974 needbytes=iacc*sizeof(uLong); 4975 #if DECDPUN==1 4976 zoff=(iacc+7)/8; /* items to offset by */ 4977 needbytes+=zoff*8; 4978 #endif 4979 if (needbytes>(Int)sizeof(zaccbuff)) { 4980 allocacc=(uLong *)malloc(needbytes); 4981 zacc=(uLong *)allocacc;} 4982 if (zlhi==NULL||zrhi==NULL||zacc==NULL) { 4983 *status|=DEC_Insufficient_storage; 4984 break;} 4985 4986 acc=(Unit *)zacc; /* -> target Unit array */ 4987 #if DECDPUN==1 4988 zacc+=zoff; /* start uLong accumulator to right */ 4989 #endif 4990 4991 /* assemble the chunked copies of the left and right sides */ 4992 for (count=lhs->digits, cup=lhs->lsu, lip=zlhi; count>0; lip++) 4993 for (p=0, *lip=0; p<FASTDIGS && count>0; 4994 p+=DECDPUN, cup++, count-=DECDPUN) 4995 *lip+=*cup*powers[p]; 4996 lmsi=lip-1; /* save -> msi */ 4997 for (count=rhs->digits, cup=rhs->lsu, rip=zrhi; count>0; rip++) 4998 for (p=0, *rip=0; p<FASTDIGS && count>0; 4999 p+=DECDPUN, cup++, count-=DECDPUN) 5000 *rip+=*cup*powers[p]; 5001 rmsi=rip-1; /* save -> msi */ 5002 5003 /* zero the accumulator */ 5004 for (lp=zacc; lp<zacc+iacc; lp++) *lp=0; 5005 5006 /* Start the multiplication */ 5007 /* Resolving carries can dominate the cost of accumulating the */ 5008 /* partial products, so this is only done when necessary. */ 5009 /* Each uLong item in the accumulator can hold values up to */ 5010 /* 2**64-1, and each partial product can be as large as */ 5011 /* (10**FASTDIGS-1)**2. When FASTDIGS=9, this can be added to */ 5012 /* itself 18.4 times in a uLong without overflowing, so during */ 5013 /* the main calculation resolution is carried out every 18th */ 5014 /* add -- every 162 digits. Similarly, when FASTDIGS=8, the */ 5015 /* partial products can be added to themselves 1844.6 times in */ 5016 /* a uLong without overflowing, so intermediate carry */ 5017 /* resolution occurs only every 14752 digits. Hence for common */ 5018 /* short numbers usually only the one final carry resolution */ 5019 /* occurs. */ 5020 /* (The count is set via FASTLAZY to simplify experiments to */ 5021 /* measure the value of this approach: a 35% improvement on a */ 5022 /* [34x34] multiply.) */ 5023 lazy=FASTLAZY; /* carry delay count */ 5024 for (rip=zrhi; rip<=rmsi; rip++) { /* over each item in rhs */ 5025 lp=zacc+(rip-zrhi); /* where to add the lhs */ 5026 for (lip=zlhi; lip<=lmsi; lip++, lp++) { /* over each item in lhs */ 5027 *lp+=(uLong)(*lip)*(*rip); /* [this should in-line] */ 5028 } /* lip loop */ 5029 lazy--; 5030 if (lazy>0 && rip!=rmsi) continue; 5031 lazy=FASTLAZY; /* reset delay count */ 5032 /* spin up the accumulator resolving overflows */ 5033 for (lp=zacc; lp<zacc+iacc; lp++) { 5034 if (*lp<FASTBASE) continue; /* it fits */ 5035 lcarry=*lp/FASTBASE; /* top part [slow divide] */ 5036 /* lcarry can exceed 2**32-1, so check again; this check */ 5037 /* and occasional extra divide (slow) is well worth it, as */ 5038 /* it allows FASTLAZY to be increased to 18 rather than 4 */ 5039 /* in the FASTDIGS=9 case */ 5040 if (lcarry<FASTBASE) carry=(uInt)lcarry; /* [usual] */ 5041 else { /* two-place carry [fairly rare] */ 5042 uInt carry2=(uInt)(lcarry/FASTBASE); /* top top part */ 5043 *(lp+2)+=carry2; /* add to item+2 */ 5044 *lp-=((uLong)FASTBASE*FASTBASE*carry2); /* [slow] */ 5045 carry=(uInt)(lcarry-((uLong)FASTBASE*carry2)); /* [inline] */ 5046 } 5047 *(lp+1)+=carry; /* add to item above [inline] */ 5048 *lp-=((uLong)FASTBASE*carry); /* [inline] */ 5049 } /* carry resolution */ 5050 } /* rip loop */ 5051 5052 /* The multiplication is complete; time to convert back into */ 5053 /* units. This can be done in-place in the accumulator and in */ 5054 /* 32-bit operations, because carries were resolved after the */ 5055 /* final add. This needs N-1 divides and multiplies for */ 5056 /* each item in the accumulator (which will become up to N */ 5057 /* units, where 2<=N<=9). */ 5058 for (lp=zacc, up=acc; lp<zacc+iacc; lp++) { 5059 uInt item=(uInt)*lp; /* decapitate to uInt */ 5060 for (p=0; p<FASTDIGS-DECDPUN; p+=DECDPUN, up++) { 5061 uInt part=item/(DECDPUNMAX+1); 5062 *up=(Unit)(item-(part*(DECDPUNMAX+1))); 5063 item=part; 5064 } /* p */ 5065 *up=(Unit)item; up++; /* [final needs no division] */ 5066 } /* lp */ 5067 accunits=up-acc; /* count of units */ 5068 } 5069 else { /* here to use units directly, without chunking ['old code'] */ 5070 #endif 5071 5072 /* if accumulator will be too long for local storage, then allocate */ 5073 acc=accbuff; /* -> assume buffer for accumulator */ 5074 needbytes=(D2U(lhs->digits)+D2U(rhs->digits))*sizeof(Unit); 5075 if (needbytes>(Int)sizeof(accbuff)) { 5076 allocacc=(Unit *)malloc(needbytes); 5077 if (allocacc==NULL) {*status|=DEC_Insufficient_storage; break;} 5078 acc=(Unit *)allocacc; /* use the allocated space */ 5079 } 5080 5081 /* Now the main long multiplication loop */ 5082 /* Unlike the equivalent in the IBM Java implementation, there */ 5083 /* is no advantage in calculating from msu to lsu. So, do it */ 5084 /* by the book, as it were. */ 5085 /* Each iteration calculates ACC=ACC+MULTAND*MULT */ 5086 accunits=1; /* accumulator starts at '0' */ 5087 *acc=0; /* .. (lsu=0) */ 5088 shift=0; /* no multiplicand shift at first */ 5089 madlength=D2U(lhs->digits); /* this won't change */ 5090 mermsup=rhs->lsu+D2U(rhs->digits); /* -> msu+1 of multiplier */ 5091 5092 for (mer=rhs->lsu; mer<mermsup; mer++) { 5093 /* Here, *mer is the next Unit in the multiplier to use */ 5094 /* If non-zero [optimization] add it... */ 5095 if (*mer!=0) accunits=decUnitAddSub(&acc[shift], accunits-shift, 5096 lhs->lsu, madlength, 0, 5097 &acc[shift], *mer) 5098 + shift; 5099 else { /* extend acc with a 0; it will be used shortly */ 5100 *(acc+accunits)=0; /* [this avoids length of <=0 later] */ 5101 accunits++; 5102 } 5103 /* multiply multiplicand by 10**DECDPUN for next Unit to left */ 5104 shift++; /* add this for 'logical length' */ 5105 } /* n */ 5106 #if FASTMUL 5107 } /* unchunked units */ 5108 #endif 5109 /* common end-path */ 5110 #if DECTRACE 5111 decDumpAr('*', acc, accunits); /* Show exact result */ 5112 #endif 5113 5114 /* acc now contains the exact result of the multiplication, */ 5115 /* possibly with a leading zero unit; build the decNumber from */ 5116 /* it, noting if any residue */ 5117 res->bits=bits; /* set sign */ 5118 res->digits=decGetDigits(acc, accunits); /* count digits exactly */ 5119 5120 /* There can be a 31-bit wrap in calculating the exponent. */ 5121 /* This can only happen if both input exponents are negative and */ 5122 /* both their magnitudes are large. If there was a wrap, set a */ 5123 /* safe very negative exponent, from which decFinalize() will */ 5124 /* raise a hard underflow shortly. */ 5125 exponent=lhs->exponent+rhs->exponent; /* calculate exponent */ 5126 if (lhs->exponent<0 && rhs->exponent<0 && exponent>0) 5127 exponent=-2*DECNUMMAXE; /* force underflow */ 5128 res->exponent=exponent; /* OK to overwrite now */ 5129 5130 5131 /* Set the coefficient. If any rounding, residue records */ 5132 decSetCoeff(res, set, acc, res->digits, &residue, status); 5133 decFinish(res, set, &residue, status); /* final cleanup */ 5134 } while(0); /* end protected */ 5135 5136 if (allocacc!=NULL) free(allocacc); /* drop any storage used */ 5137 #if DECSUBSET 5138 if (allocrhs!=NULL) free(allocrhs); /* .. */ 5139 if (alloclhs!=NULL) free(alloclhs); /* .. */ 5140 #endif 5141 #if FASTMUL 5142 if (allocrhi!=NULL) free(allocrhi); /* .. */ 5143 if (alloclhi!=NULL) free(alloclhi); /* .. */ 5144 #endif 5145 return res; 5146 } /* decMultiplyOp */ 5147 5148 /* ------------------------------------------------------------------ */ 5149 /* decExpOp -- effect exponentiation */ 5150 /* */ 5151 /* This computes C = exp(A) */ 5152 /* */ 5153 /* res is C, the result. C may be A */ 5154 /* rhs is A */ 5155 /* set is the context; note that rounding mode has no effect */ 5156 /* */ 5157 /* C must have space for set->digits digits. status is updated but */ 5158 /* not set. */ 5159 /* */ 5160 /* Restrictions: */ 5161 /* */ 5162 /* digits, emax, and -emin in the context must be less than */ 5163 /* 2*DEC_MAX_MATH (1999998), and the rhs must be within these */ 5164 /* bounds or a zero. This is an internal routine, so these */ 5165 /* restrictions are contractual and not enforced. */ 5166 /* */ 5167 /* A finite result is rounded using DEC_ROUND_HALF_EVEN; it will */ 5168 /* almost always be correctly rounded, but may be up to 1 ulp in */ 5169 /* error in rare cases. */ 5170 /* */ 5171 /* Finite results will always be full precision and Inexact, except */ 5172 /* when A is a zero or -Infinity (giving 1 or 0 respectively). */ 5173 /* ------------------------------------------------------------------ */ 5174 /* This approach used here is similar to the algorithm described in */ 5175 /* */ 5176 /* Variable Precision Exponential Function, T. E. Hull and */ 5177 /* A. Abrham, ACM Transactions on Mathematical Software, Vol 12 #2, */ 5178 /* pp79-91, ACM, June 1986. */ 5179 /* */ 5180 /* with the main difference being that the iterations in the series */ 5181 /* evaluation are terminated dynamically (which does not require the */ 5182 /* extra variable-precision variables which are expensive in this */ 5183 /* context). */ 5184 /* */ 5185 /* The error analysis in Hull & Abrham's paper applies except for the */ 5186 /* round-off error accumulation during the series evaluation. This */ 5187 /* code does not precalculate the number of iterations and so cannot */ 5188 /* use Horner's scheme. Instead, the accumulation is done at double- */ 5189 /* precision, which ensures that the additions of the terms are exact */ 5190 /* and do not accumulate round-off (and any round-off errors in the */ 5191 /* terms themselves move 'to the right' faster than they can */ 5192 /* accumulate). This code also extends the calculation by allowing, */ 5193 /* in the spirit of other decNumber operators, the input to be more */ 5194 /* precise than the result (the precision used is based on the more */ 5195 /* precise of the input or requested result). */ 5196 /* */ 5197 /* Implementation notes: */ 5198 /* */ 5199 /* 1. This is separated out as decExpOp so it can be called from */ 5200 /* other Mathematical functions (notably Ln) with a wider range */ 5201 /* than normal. In particular, it can handle the slightly wider */ 5202 /* (double) range needed by Ln (which has to be able to calculate */ 5203 /* exp(-x) where x can be the tiniest number (Ntiny). */ 5204 /* */ 5205 /* 2. Normalizing x to be <=0.1 (instead of <=1) reduces loop */ 5206 /* iterations by appoximately a third with additional (although */ 5207 /* diminishing) returns as the range is reduced to even smaller */ 5208 /* fractions. However, h (the power of 10 used to correct the */ 5209 /* result at the end, see below) must be kept <=8 as otherwise */ 5210 /* the final result cannot be computed. Hence the leverage is a */ 5211 /* sliding value (8-h), where potentially the range is reduced */ 5212 /* more for smaller values. */ 5213 /* */ 5214 /* The leverage that can be applied in this way is severely */ 5215 /* limited by the cost of the raise-to-the power at the end, */ 5216 /* which dominates when the number of iterations is small (less */ 5217 /* than ten) or when rhs is short. As an example, the adjustment */ 5218 /* x**10,000,000 needs 31 multiplications, all but one full-width. */ 5219 /* */ 5220 /* 3. The restrictions (especially precision) could be raised with */ 5221 /* care, but the full decNumber range seems very hard within the */ 5222 /* 32-bit limits. */ 5223 /* */ 5224 /* 4. The working precisions for the static buffers are twice the */ 5225 /* obvious size to allow for calls from decNumberPower. */ 5226 /* ------------------------------------------------------------------ */ 5227 decNumber * decExpOp(decNumber *res, const decNumber *rhs, 5228 decContext *set, uInt *status) { 5229 uInt ignore=0; /* working status */ 5230 Int h; /* adjusted exponent for 0.xxxx */ 5231 Int p; /* working precision */ 5232 Int residue; /* rounding residue */ 5233 uInt needbytes; /* for space calculations */ 5234 const decNumber *x=rhs; /* (may point to safe copy later) */ 5235 decContext aset, tset, dset; /* working contexts */ 5236 Int comp; /* work */ 5237 5238 /* the argument is often copied to normalize it, so (unusually) it */ 5239 /* is treated like other buffers, using DECBUFFER, +1 in case */ 5240 /* DECBUFFER is 0 */ 5241 decNumber bufr[D2N(DECBUFFER*2+1)]; 5242 decNumber *allocrhs=NULL; /* non-NULL if rhs buffer allocated */ 5243 5244 /* the working precision will be no more than set->digits+8+1 */ 5245 /* so for on-stack buffers DECBUFFER+9 is used, +1 in case DECBUFFER */ 5246 /* is 0 (and twice that for the accumulator) */ 5247 5248 /* buffer for t, term (working precision plus) */ 5249 decNumber buft[D2N(DECBUFFER*2+9+1)]; 5250 decNumber *allocbuft=NULL; /* -> allocated buft, iff allocated */ 5251 decNumber *t=buft; /* term */ 5252 /* buffer for a, accumulator (working precision * 2), at least 9 */ 5253 decNumber bufa[D2N(DECBUFFER*4+18+1)]; 5254 decNumber *allocbufa=NULL; /* -> allocated bufa, iff allocated */ 5255 decNumber *a=bufa; /* accumulator */ 5256 /* decNumber for the divisor term; this needs at most 9 digits */ 5257 /* and so can be fixed size [16 so can use standard context] */ 5258 decNumber bufd[D2N(16)]; 5259 decNumber *d=bufd; /* divisor */ 5260 decNumber numone; /* constant 1 */ 5261 5262 #if DECCHECK 5263 Int iterations=0; /* for later sanity check */ 5264 if (decCheckOperands(res, DECUNUSED, rhs, set)) return res; 5265 #endif 5266 5267 do { /* protect allocated storage */ 5268 if (SPECIALARG) { /* handle infinities and NaNs */ 5269 if (decNumberIsInfinite(rhs)) { /* an infinity */ 5270 if (decNumberIsNegative(rhs)) /* -Infinity -> +0 */ 5271 uprv_decNumberZero(res); 5272 else uprv_decNumberCopy(res, rhs); /* +Infinity -> self */ 5273 } 5274 else decNaNs(res, rhs, NULL, set, status); /* a NaN */ 5275 break;} 5276 5277 if (ISZERO(rhs)) { /* zeros -> exact 1 */ 5278 uprv_decNumberZero(res); /* make clean 1 */ 5279 *res->lsu=1; /* .. */ 5280 break;} /* [no status to set] */ 5281 5282 /* e**x when 0 < x < 0.66 is < 1+3x/2, hence can fast-path */ 5283 /* positive and negative tiny cases which will result in inexact */ 5284 /* 1. This also allows the later add-accumulate to always be */ 5285 /* exact (because its length will never be more than twice the */ 5286 /* working precision). */ 5287 /* The comparator (tiny) needs just one digit, so use the */ 5288 /* decNumber d for it (reused as the divisor, etc., below); its */ 5289 /* exponent is such that if x is positive it will have */ 5290 /* set->digits-1 zeros between the decimal point and the digit, */ 5291 /* which is 4, and if x is negative one more zero there as the */ 5292 /* more precise result will be of the form 0.9999999 rather than */ 5293 /* 1.0000001. Hence, tiny will be 0.0000004 if digits=7 and x>0 */ 5294 /* or 0.00000004 if digits=7 and x<0. If RHS not larger than */ 5295 /* this then the result will be 1.000000 */ 5296 uprv_decNumberZero(d); /* clean */ 5297 *d->lsu=4; /* set 4 .. */ 5298 d->exponent=-set->digits; /* * 10**(-d) */ 5299 if (decNumberIsNegative(rhs)) d->exponent--; /* negative case */ 5300 comp=decCompare(d, rhs, 1); /* signless compare */ 5301 if (comp==BADINT) { 5302 *status|=DEC_Insufficient_storage; 5303 break;} 5304 if (comp>=0) { /* rhs < d */ 5305 Int shift=set->digits-1; 5306 uprv_decNumberZero(res); /* set 1 */ 5307 *res->lsu=1; /* .. */ 5308 res->digits=decShiftToMost(res->lsu, 1, shift); 5309 res->exponent=-shift; /* make 1.0000... */ 5310 *status|=DEC_Inexact | DEC_Rounded; /* .. inexactly */ 5311 break;} /* tiny */ 5312 5313 /* set up the context to be used for calculating a, as this is */ 5314 /* used on both paths below */ 5315 uprv_decContextDefault(&aset, DEC_INIT_DECIMAL64); 5316 /* accumulator bounds are as requested (could underflow) */ 5317 aset.emax=set->emax; /* usual bounds */ 5318 aset.emin=set->emin; /* .. */ 5319 aset.clamp=0; /* and no concrete format */ 5320 5321 /* calculate the adjusted (Hull & Abrham) exponent (where the */ 5322 /* decimal point is just to the left of the coefficient msd) */ 5323 h=rhs->exponent+rhs->digits; 5324 /* if h>8 then 10**h cannot be calculated safely; however, when */ 5325 /* h=8 then exp(|rhs|) will be at least exp(1E+7) which is at */ 5326 /* least 6.59E+4342944, so (due to the restriction on Emax/Emin) */ 5327 /* overflow (or underflow to 0) is guaranteed -- so this case can */ 5328 /* be handled by simply forcing the appropriate excess */ 5329 if (h>8) { /* overflow/underflow */ 5330 /* set up here so Power call below will over or underflow to */ 5331 /* zero; set accumulator to either 2 or 0.02 */ 5332 /* [stack buffer for a is always big enough for this] */ 5333 uprv_decNumberZero(a); 5334 *a->lsu=2; /* not 1 but < exp(1) */ 5335 if (decNumberIsNegative(rhs)) a->exponent=-2; /* make 0.02 */ 5336 h=8; /* clamp so 10**h computable */ 5337 p=9; /* set a working precision */ 5338 } 5339 else { /* h<=8 */ 5340 Int maxlever=(rhs->digits>8?1:0); 5341 /* [could/should increase this for precisions >40 or so, too] */ 5342 5343 /* if h is 8, cannot normalize to a lower upper limit because */ 5344 /* the final result will not be computable (see notes above), */ 5345 /* but leverage can be applied whenever h is less than 8. */ 5346 /* Apply as much as possible, up to a MAXLEVER digits, which */ 5347 /* sets the tradeoff against the cost of the later a**(10**h). */ 5348 /* As h is increased, the working precision below also */ 5349 /* increases to compensate for the "constant digits at the */ 5350 /* front" effect. */ 5351 Int lever=MINI(8-h, maxlever); /* leverage attainable */ 5352 Int use=-rhs->digits-lever; /* exponent to use for RHS */ 5353 h+=lever; /* apply leverage selected */ 5354 if (h<0) { /* clamp */ 5355 use+=h; /* [may end up subnormal] */ 5356 h=0; 5357 } 5358 /* Take a copy of RHS if it needs normalization (true whenever x>=1) */ 5359 if (rhs->exponent!=use) { 5360 decNumber *newrhs=bufr; /* assume will fit on stack */ 5361 needbytes=sizeof(decNumber)+(D2U(rhs->digits)-1)*sizeof(Unit); 5362 if (needbytes>sizeof(bufr)) { /* need malloc space */ 5363 allocrhs=(decNumber *)malloc(needbytes); 5364 if (allocrhs==NULL) { /* hopeless -- abandon */ 5365 *status|=DEC_Insufficient_storage; 5366 break;} 5367 newrhs=allocrhs; /* use the allocated space */ 5368 } 5369 uprv_decNumberCopy(newrhs, rhs); /* copy to safe space */ 5370 newrhs->exponent=use; /* normalize; now <1 */ 5371 x=newrhs; /* ready for use */ 5372 /* decNumberShow(x); */ 5373 } 5374 5375 /* Now use the usual power series to evaluate exp(x). The */ 5376 /* series starts as 1 + x + x^2/2 ... so prime ready for the */ 5377 /* third term by setting the term variable t=x, the accumulator */ 5378 /* a=1, and the divisor d=2. */ 5379 5380 /* First determine the working precision. From Hull & Abrham */ 5381 /* this is set->digits+h+2. However, if x is 'over-precise' we */ 5382 /* need to allow for all its digits to potentially participate */ 5383 /* (consider an x where all the excess digits are 9s) so in */ 5384 /* this case use x->digits+h+2 */ 5385 p=MAXI(x->digits, set->digits)+h+2; /* [h<=8] */ 5386 5387 /* a and t are variable precision, and depend on p, so space */ 5388 /* must be allocated for them if necessary */ 5389 5390 /* the accumulator needs to be able to hold 2p digits so that */ 5391 /* the additions on the second and subsequent iterations are */ 5392 /* sufficiently exact. */ 5393 needbytes=sizeof(decNumber)+(D2U(p*2)-1)*sizeof(Unit); 5394 if (needbytes>sizeof(bufa)) { /* need malloc space */ 5395 allocbufa=(decNumber *)malloc(needbytes); 5396 if (allocbufa==NULL) { /* hopeless -- abandon */ 5397 *status|=DEC_Insufficient_storage; 5398 break;} 5399 a=allocbufa; /* use the allocated space */ 5400 } 5401 /* the term needs to be able to hold p digits (which is */ 5402 /* guaranteed to be larger than x->digits, so the initial copy */ 5403 /* is safe); it may also be used for the raise-to-power */ 5404 /* calculation below, which needs an extra two digits */ 5405 needbytes=sizeof(decNumber)+(D2U(p+2)-1)*sizeof(Unit); 5406 if (needbytes>sizeof(buft)) { /* need malloc space */ 5407 allocbuft=(decNumber *)malloc(needbytes); 5408 if (allocbuft==NULL) { /* hopeless -- abandon */ 5409 *status|=DEC_Insufficient_storage; 5410 break;} 5411 t=allocbuft; /* use the allocated space */ 5412 } 5413 5414 uprv_decNumberCopy(t, x); /* term=x */ 5415 uprv_decNumberZero(a); *a->lsu=1; /* accumulator=1 */ 5416 uprv_decNumberZero(d); *d->lsu=2; /* divisor=2 */ 5417 uprv_decNumberZero(&numone); *numone.lsu=1; /* constant 1 for increment */ 5418 5419 /* set up the contexts for calculating a, t, and d */ 5420 uprv_decContextDefault(&tset, DEC_INIT_DECIMAL64); 5421 dset=tset; 5422 /* accumulator bounds are set above, set precision now */ 5423 aset.digits=p*2; /* double */ 5424 /* term bounds avoid any underflow or overflow */ 5425 tset.digits=p; 5426 tset.emin=DEC_MIN_EMIN; /* [emax is plenty] */ 5427 /* [dset.digits=16, etc., are sufficient] */ 5428 5429 /* finally ready to roll */ 5430 for (;;) { 5431 #if DECCHECK 5432 iterations++; 5433 #endif 5434 /* only the status from the accumulation is interesting */ 5435 /* [but it should remain unchanged after first add] */ 5436 decAddOp(a, a, t, &aset, 0, status); /* a=a+t */ 5437 decMultiplyOp(t, t, x, &tset, &ignore); /* t=t*x */ 5438 decDivideOp(t, t, d, &tset, DIVIDE, &ignore); /* t=t/d */ 5439 /* the iteration ends when the term cannot affect the result, */ 5440 /* if rounded to p digits, which is when its value is smaller */ 5441 /* than the accumulator by p+1 digits. There must also be */ 5442 /* full precision in a. */ 5443 if (((a->digits+a->exponent)>=(t->digits+t->exponent+p+1)) 5444 && (a->digits>=p)) break; 5445 decAddOp(d, d, &numone, &dset, 0, &ignore); /* d=d+1 */ 5446 } /* iterate */ 5447 5448 #if DECCHECK 5449 /* just a sanity check; comment out test to show always */ 5450 if (iterations>p+3) 5451 printf("Exp iterations=%ld, status=%08lx, p=%ld, d=%ld\n", 5452 (LI)iterations, (LI)*status, (LI)p, (LI)x->digits); 5453 #endif 5454 } /* h<=8 */ 5455 5456 /* apply postconditioning: a=a**(10**h) -- this is calculated */ 5457 /* at a slightly higher precision than Hull & Abrham suggest */ 5458 if (h>0) { 5459 Int seenbit=0; /* set once a 1-bit is seen */ 5460 Int i; /* counter */ 5461 Int n=powers[h]; /* always positive */ 5462 aset.digits=p+2; /* sufficient precision */ 5463 /* avoid the overhead and many extra digits of decNumberPower */ 5464 /* as all that is needed is the short 'multipliers' loop; here */ 5465 /* accumulate the answer into t */ 5466 uprv_decNumberZero(t); *t->lsu=1; /* acc=1 */ 5467 for (i=1;;i++){ /* for each bit [top bit ignored] */ 5468 /* abandon if have had overflow or terminal underflow */ 5469 if (*status & (DEC_Overflow|DEC_Underflow)) { /* interesting? */ 5470 if (*status&DEC_Overflow || ISZERO(t)) break;} 5471 n=n<<1; /* move next bit to testable position */ 5472 if (n<0) { /* top bit is set */ 5473 seenbit=1; /* OK, have a significant bit */ 5474 decMultiplyOp(t, t, a, &aset, status); /* acc=acc*x */ 5475 } 5476 if (i==31) break; /* that was the last bit */ 5477 if (!seenbit) continue; /* no need to square 1 */ 5478 decMultiplyOp(t, t, t, &aset, status); /* acc=acc*acc [square] */ 5479 } /*i*/ /* 32 bits */ 5480 /* decNumberShow(t); */ 5481 a=t; /* and carry on using t instead of a */ 5482 } 5483 5484 /* Copy and round the result to res */ 5485 residue=1; /* indicate dirt to right .. */ 5486 if (ISZERO(a)) residue=0; /* .. unless underflowed to 0 */ 5487 aset.digits=set->digits; /* [use default rounding] */ 5488 decCopyFit(res, a, &aset, &residue, status); /* copy & shorten */ 5489 decFinish(res, set, &residue, status); /* cleanup/set flags */ 5490 } while(0); /* end protected */ 5491 5492 if (allocrhs !=NULL) free(allocrhs); /* drop any storage used */ 5493 if (allocbufa!=NULL) free(allocbufa); /* .. */ 5494 if (allocbuft!=NULL) free(allocbuft); /* .. */ 5495 /* [status is handled by caller] */ 5496 return res; 5497 } /* decExpOp */ 5498 5499 /* ------------------------------------------------------------------ */ 5500 /* Initial-estimate natural logarithm table */ 5501 /* */ 5502 /* LNnn -- 90-entry 16-bit table for values from .10 through .99. */ 5503 /* The result is a 4-digit encode of the coefficient (c=the */ 5504 /* top 14 bits encoding 0-9999) and a 2-digit encode of the */ 5505 /* exponent (e=the bottom 2 bits encoding 0-3) */ 5506 /* */ 5507 /* The resulting value is given by: */ 5508 /* */ 5509 /* v = -c * 10**(-e-3) */ 5510 /* */ 5511 /* where e and c are extracted from entry k = LNnn[x-10] */ 5512 /* where x is truncated (NB) into the range 10 through 99, */ 5513 /* and then c = k>>2 and e = k&3. */ 5514 /* ------------------------------------------------------------------ */ 5515 const uShort LNnn[90]={9016, 8652, 8316, 8008, 7724, 7456, 7208, 5516 6972, 6748, 6540, 6340, 6148, 5968, 5792, 5628, 5464, 5312, 5517 5164, 5020, 4884, 4748, 4620, 4496, 4376, 4256, 4144, 4032, 5518 39233, 38181, 37157, 36157, 35181, 34229, 33297, 32389, 31501, 30629, 5519 29777, 28945, 28129, 27329, 26545, 25777, 25021, 24281, 23553, 22837, 5520 22137, 21445, 20769, 20101, 19445, 18801, 18165, 17541, 16925, 16321, 5521 15721, 15133, 14553, 13985, 13421, 12865, 12317, 11777, 11241, 10717, 5522 10197, 9685, 9177, 8677, 8185, 7697, 7213, 6737, 6269, 5801, 5523 5341, 4889, 4437, 39930, 35534, 31186, 26886, 22630, 18418, 14254, 5524 10130, 6046, 20055}; 5525 5526 /* ------------------------------------------------------------------ */ 5527 /* decLnOp -- effect natural logarithm */ 5528 /* */ 5529 /* This computes C = ln(A) */ 5530 /* */ 5531 /* res is C, the result. C may be A */ 5532 /* rhs is A */ 5533 /* set is the context; note that rounding mode has no effect */ 5534 /* */ 5535 /* C must have space for set->digits digits. */ 5536 /* */ 5537 /* Notable cases: */ 5538 /* A<0 -> Invalid */ 5539 /* A=0 -> -Infinity (Exact) */ 5540 /* A=+Infinity -> +Infinity (Exact) */ 5541 /* A=1 exactly -> 0 (Exact) */ 5542 /* */ 5543 /* Restrictions (as for Exp): */ 5544 /* */ 5545 /* digits, emax, and -emin in the context must be less than */ 5546 /* DEC_MAX_MATH+11 (1000010), and the rhs must be within these */ 5547 /* bounds or a zero. This is an internal routine, so these */ 5548 /* restrictions are contractual and not enforced. */ 5549 /* */ 5550 /* A finite result is rounded using DEC_ROUND_HALF_EVEN; it will */ 5551 /* almost always be correctly rounded, but may be up to 1 ulp in */ 5552 /* error in rare cases. */ 5553 /* ------------------------------------------------------------------ */ 5554 /* The result is calculated using Newton's method, with each */ 5555 /* iteration calculating a' = a + x * exp(-a) - 1. See, for example, */ 5556 /* Epperson 1989. */ 5557 /* */ 5558 /* The iteration ends when the adjustment x*exp(-a)-1 is tiny enough. */ 5559 /* This has to be calculated at the sum of the precision of x and the */ 5560 /* working precision. */ 5561 /* */ 5562 /* Implementation notes: */ 5563 /* */ 5564 /* 1. This is separated out as decLnOp so it can be called from */ 5565 /* other Mathematical functions (e.g., Log 10) with a wider range */ 5566 /* than normal. In particular, it can handle the slightly wider */ 5567 /* (+9+2) range needed by a power function. */ 5568 /* */ 5569 /* 2. The speed of this function is about 10x slower than exp, as */ 5570 /* it typically needs 4-6 iterations for short numbers, and the */ 5571 /* extra precision needed adds a squaring effect, twice. */ 5572 /* */ 5573 /* 3. Fastpaths are included for ln(10) and ln(2), up to length 40, */ 5574 /* as these are common requests. ln(10) is used by log10(x). */ 5575 /* */ 5576 /* 4. An iteration might be saved by widening the LNnn table, and */ 5577 /* would certainly save at least one if it were made ten times */ 5578 /* bigger, too (for truncated fractions 0.100 through 0.999). */ 5579 /* However, for most practical evaluations, at least four or five */ 5580 /* iterations will be neede -- so this would only speed up by */ 5581 /* 20-25% and that probably does not justify increasing the table */ 5582 /* size. */ 5583 /* */ 5584 /* 5. The static buffers are larger than might be expected to allow */ 5585 /* for calls from decNumberPower. */ 5586 /* ------------------------------------------------------------------ */ 5587 decNumber * decLnOp(decNumber *res, const decNumber *rhs, 5588 decContext *set, uInt *status) { 5589 uInt ignore=0; /* working status accumulator */ 5590 uInt needbytes; /* for space calculations */ 5591 Int residue; /* rounding residue */ 5592 Int r; /* rhs=f*10**r [see below] */ 5593 Int p; /* working precision */ 5594 Int pp; /* precision for iteration */ 5595 Int t; /* work */ 5596 5597 /* buffers for a (accumulator, typically precision+2) and b */ 5598 /* (adjustment calculator, same size) */ 5599 decNumber bufa[D2N(DECBUFFER+12)]; 5600 decNumber *allocbufa=NULL; /* -> allocated bufa, iff allocated */ 5601 decNumber *a=bufa; /* accumulator/work */ 5602 decNumber bufb[D2N(DECBUFFER*2+2)]; 5603 decNumber *allocbufb=NULL; /* -> allocated bufa, iff allocated */ 5604 decNumber *b=bufb; /* adjustment/work */ 5605 5606 decNumber numone; /* constant 1 */ 5607 decNumber cmp; /* work */ 5608 decContext aset, bset; /* working contexts */ 5609 5610 #if DECCHECK 5611 Int iterations=0; /* for later sanity check */ 5612 if (decCheckOperands(res, DECUNUSED, rhs, set)) return res; 5613 #endif 5614 5615 do { /* protect allocated storage */ 5616 if (SPECIALARG) { /* handle infinities and NaNs */ 5617 if (decNumberIsInfinite(rhs)) { /* an infinity */ 5618 if (decNumberIsNegative(rhs)) /* -Infinity -> error */ 5619 *status|=DEC_Invalid_operation; 5620 else uprv_decNumberCopy(res, rhs); /* +Infinity -> self */ 5621 } 5622 else decNaNs(res, rhs, NULL, set, status); /* a NaN */ 5623 break;} 5624 5625 if (ISZERO(rhs)) { /* +/- zeros -> -Infinity */ 5626 uprv_decNumberZero(res); /* make clean */ 5627 res->bits=DECINF|DECNEG; /* set - infinity */ 5628 break;} /* [no status to set] */ 5629 5630 /* Non-zero negatives are bad... */ 5631 if (decNumberIsNegative(rhs)) { /* -x -> error */ 5632 *status|=DEC_Invalid_operation; 5633 break;} 5634 5635 /* Here, rhs is positive, finite, and in range */ 5636 5637 /* lookaside fastpath code for ln(2) and ln(10) at common lengths */ 5638 if (rhs->exponent==0 && set->digits<=40) { 5639 #if DECDPUN==1 5640 if (rhs->lsu[0]==0 && rhs->lsu[1]==1 && rhs->digits==2) { /* ln(10) */ 5641 #else 5642 if (rhs->lsu[0]==10 && rhs->digits==2) { /* ln(10) */ 5643 #endif 5644 aset=*set; aset.round=DEC_ROUND_HALF_EVEN; 5645 #define LN10 "2.302585092994045684017991454684364207601" 5646 uprv_decNumberFromString(res, LN10, &aset); 5647 *status|=(DEC_Inexact | DEC_Rounded); /* is inexact */ 5648 break;} 5649 if (rhs->lsu[0]==2 && rhs->digits==1) { /* ln(2) */ 5650 aset=*set; aset.round=DEC_ROUND_HALF_EVEN; 5651 #define LN2 "0.6931471805599453094172321214581765680755" 5652 uprv_decNumberFromString(res, LN2, &aset); 5653 *status|=(DEC_Inexact | DEC_Rounded); 5654 break;} 5655 } /* integer and short */ 5656 5657 /* Determine the working precision. This is normally the */ 5658 /* requested precision + 2, with a minimum of 9. However, if */ 5659 /* the rhs is 'over-precise' then allow for all its digits to */ 5660 /* potentially participate (consider an rhs where all the excess */ 5661 /* digits are 9s) so in this case use rhs->digits+2. */ 5662 p=MAXI(rhs->digits, MAXI(set->digits, 7))+2; 5663 5664 /* Allocate space for the accumulator and the high-precision */ 5665 /* adjustment calculator, if necessary. The accumulator must */ 5666 /* be able to hold p digits, and the adjustment up to */ 5667 /* rhs->digits+p digits. They are also made big enough for 16 */ 5668 /* digits so that they can be used for calculating the initial */ 5669 /* estimate. */ 5670 needbytes=sizeof(decNumber)+(D2U(MAXI(p,16))-1)*sizeof(Unit); 5671 if (needbytes>sizeof(bufa)) { /* need malloc space */ 5672 allocbufa=(decNumber *)malloc(needbytes); 5673 if (allocbufa==NULL) { /* hopeless -- abandon */ 5674 *status|=DEC_Insufficient_storage; 5675 break;} 5676 a=allocbufa; /* use the allocated space */ 5677 } 5678 pp=p+rhs->digits; 5679 needbytes=sizeof(decNumber)+(D2U(MAXI(pp,16))-1)*sizeof(Unit); 5680 if (needbytes>sizeof(bufb)) { /* need malloc space */ 5681 allocbufb=(decNumber *)malloc(needbytes); 5682 if (allocbufb==NULL) { /* hopeless -- abandon */ 5683 *status|=DEC_Insufficient_storage; 5684 break;} 5685 b=allocbufb; /* use the allocated space */ 5686 } 5687 5688 /* Prepare an initial estimate in acc. Calculate this by */ 5689 /* considering the coefficient of x to be a normalized fraction, */ 5690 /* f, with the decimal point at far left and multiplied by */ 5691 /* 10**r. Then, rhs=f*10**r and 0.1<=f<1, and */ 5692 /* ln(x) = ln(f) + ln(10)*r */ 5693 /* Get the initial estimate for ln(f) from a small lookup */ 5694 /* table (see above) indexed by the first two digits of f, */ 5695 /* truncated. */ 5696 5697 uprv_decContextDefault(&aset, DEC_INIT_DECIMAL64); /* 16-digit extended */ 5698 r=rhs->exponent+rhs->digits; /* 'normalised' exponent */ 5699 uprv_decNumberFromInt32(a, r); /* a=r */ 5700 uprv_decNumberFromInt32(b, 2302585); /* b=ln(10) (2.302585) */ 5701 b->exponent=-6; /* .. */ 5702 decMultiplyOp(a, a, b, &aset, &ignore); /* a=a*b */ 5703 /* now get top two digits of rhs into b by simple truncate and */ 5704 /* force to integer */ 5705 residue=0; /* (no residue) */ 5706 aset.digits=2; aset.round=DEC_ROUND_DOWN; 5707 decCopyFit(b, rhs, &aset, &residue, &ignore); /* copy & shorten */ 5708 b->exponent=0; /* make integer */ 5709 t=decGetInt(b); /* [cannot fail] */ 5710 if (t<10) t=X10(t); /* adjust single-digit b */ 5711 t=LNnn[t-10]; /* look up ln(b) */ 5712 uprv_decNumberFromInt32(b, t>>2); /* b=ln(b) coefficient */ 5713 b->exponent=-(t&3)-3; /* set exponent */ 5714 b->bits=DECNEG; /* ln(0.10)->ln(0.99) always -ve */ 5715 aset.digits=16; aset.round=DEC_ROUND_HALF_EVEN; /* restore */ 5716 decAddOp(a, a, b, &aset, 0, &ignore); /* acc=a+b */ 5717 /* the initial estimate is now in a, with up to 4 digits correct. */ 5718 /* When rhs is at or near Nmax the estimate will be low, so we */ 5719 /* will approach it from below, avoiding overflow when calling exp. */ 5720 5721 uprv_decNumberZero(&numone); *numone.lsu=1; /* constant 1 for adjustment */ 5722 5723 /* accumulator bounds are as requested (could underflow, but */ 5724 /* cannot overflow) */ 5725 aset.emax=set->emax; 5726 aset.emin=set->emin; 5727 aset.clamp=0; /* no concrete format */ 5728 /* set up a context to be used for the multiply and subtract */ 5729 bset=aset; 5730 bset.emax=DEC_MAX_MATH*2; /* use double bounds for the */ 5731 bset.emin=-DEC_MAX_MATH*2; /* adjustment calculation */ 5732 /* [see decExpOp call below] */ 5733 /* for each iteration double the number of digits to calculate, */ 5734 /* up to a maximum of p */ 5735 pp=9; /* initial precision */ 5736 /* [initially 9 as then the sequence starts 7+2, 16+2, and */ 5737 /* 34+2, which is ideal for standard-sized numbers] */ 5738 aset.digits=pp; /* working context */ 5739 bset.digits=pp+rhs->digits; /* wider context */ 5740 for (;;) { /* iterate */ 5741 #if DECCHECK 5742 iterations++; 5743 if (iterations>24) break; /* consider 9 * 2**24 */ 5744 #endif 5745 /* calculate the adjustment (exp(-a)*x-1) into b. This is a */ 5746 /* catastrophic subtraction but it really is the difference */ 5747 /* from 1 that is of interest. */ 5748 /* Use the internal entry point to Exp as it allows the double */ 5749 /* range for calculating exp(-a) when a is the tiniest subnormal. */ 5750 a->bits^=DECNEG; /* make -a */ 5751 decExpOp(b, a, &bset, &ignore); /* b=exp(-a) */ 5752 a->bits^=DECNEG; /* restore sign of a */ 5753 /* now multiply by rhs and subtract 1, at the wider precision */ 5754 decMultiplyOp(b, b, rhs, &bset, &ignore); /* b=b*rhs */ 5755 decAddOp(b, b, &numone, &bset, DECNEG, &ignore); /* b=b-1 */ 5756 5757 /* the iteration ends when the adjustment cannot affect the */ 5758 /* result by >=0.5 ulp (at the requested digits), which */ 5759 /* is when its value is smaller than the accumulator by */ 5760 /* set->digits+1 digits (or it is zero) -- this is a looser */ 5761 /* requirement than for Exp because all that happens to the */ 5762 /* accumulator after this is the final rounding (but note that */ 5763 /* there must also be full precision in a, or a=0). */ 5764 5765 if (decNumberIsZero(b) || 5766 (a->digits+a->exponent)>=(b->digits+b->exponent+set->digits+1)) { 5767 if (a->digits==p) break; 5768 if (decNumberIsZero(a)) { 5769 decCompareOp(&cmp, rhs, &numone, &aset, COMPARE, &ignore); /* rhs=1 ? */ 5770 if (cmp.lsu[0]==0) a->exponent=0; /* yes, exact 0 */ 5771 else *status|=(DEC_Inexact | DEC_Rounded); /* no, inexact */ 5772 break; 5773 } 5774 /* force padding if adjustment has gone to 0 before full length */ 5775 if (decNumberIsZero(b)) b->exponent=a->exponent-p; 5776 } 5777 5778 /* not done yet ... */ 5779 decAddOp(a, a, b, &aset, 0, &ignore); /* a=a+b for next estimate */ 5780 if (pp==p) continue; /* precision is at maximum */ 5781 /* lengthen the next calculation */ 5782 pp=pp*2; /* double precision */ 5783 if (pp>p) pp=p; /* clamp to maximum */ 5784 aset.digits=pp; /* working context */ 5785 bset.digits=pp+rhs->digits; /* wider context */ 5786 } /* Newton's iteration */ 5787 5788 #if DECCHECK 5789 /* just a sanity check; remove the test to show always */ 5790 if (iterations>24) 5791 printf("Ln iterations=%ld, status=%08lx, p=%ld, d=%ld\n", 5792 (LI)iterations, (LI)*status, (LI)p, (LI)rhs->digits); 5793 #endif 5794 5795 /* Copy and round the result to res */ 5796 residue=1; /* indicate dirt to right */ 5797 if (ISZERO(a)) residue=0; /* .. unless underflowed to 0 */ 5798 aset.digits=set->digits; /* [use default rounding] */ 5799 decCopyFit(res, a, &aset, &residue, status); /* copy & shorten */ 5800 decFinish(res, set, &residue, status); /* cleanup/set flags */ 5801 } while(0); /* end protected */ 5802 5803 if (allocbufa!=NULL) free(allocbufa); /* drop any storage used */ 5804 if (allocbufb!=NULL) free(allocbufb); /* .. */ 5805 /* [status is handled by caller] */ 5806 return res; 5807 } /* decLnOp */ 5808 5809 /* ------------------------------------------------------------------ */ 5810 /* decQuantizeOp -- force exponent to requested value */ 5811 /* */ 5812 /* This computes C = op(A, B), where op adjusts the coefficient */ 5813 /* of C (by rounding or shifting) such that the exponent (-scale) */ 5814 /* of C has the value B or matches the exponent of B. */ 5815 /* The numerical value of C will equal A, except for the effects of */ 5816 /* any rounding that occurred. */ 5817 /* */ 5818 /* res is C, the result. C may be A or B */ 5819 /* lhs is A, the number to adjust */ 5820 /* rhs is B, the requested exponent */ 5821 /* set is the context */ 5822 /* quant is 1 for quantize or 0 for rescale */ 5823 /* status is the status accumulator (this can be called without */ 5824 /* risk of control loss) */ 5825 /* */ 5826 /* C must have space for set->digits digits. */ 5827 /* */ 5828 /* Unless there is an error or the result is infinite, the exponent */ 5829 /* after the operation is guaranteed to be that requested. */ 5830 /* ------------------------------------------------------------------ */ 5831 static decNumber * decQuantizeOp(decNumber *res, const decNumber *lhs, 5832 const decNumber *rhs, decContext *set, 5833 Flag quant, uInt *status) { 5834 #if DECSUBSET 5835 decNumber *alloclhs=NULL; /* non-NULL if rounded lhs allocated */ 5836 decNumber *allocrhs=NULL; /* .., rhs */ 5837 #endif 5838 const decNumber *inrhs=rhs; /* save original rhs */ 5839 Int reqdigits=set->digits; /* requested DIGITS */ 5840 Int reqexp; /* requested exponent [-scale] */ 5841 Int residue=0; /* rounding residue */ 5842 Int etiny=set->emin-(reqdigits-1); 5843 5844 #if DECCHECK 5845 if (decCheckOperands(res, lhs, rhs, set)) return res; 5846 #endif 5847 5848 do { /* protect allocated storage */ 5849 #if DECSUBSET 5850 if (!set->extended) { 5851 /* reduce operands and set lostDigits status, as needed */ 5852 if (lhs->digits>reqdigits) { 5853 alloclhs=decRoundOperand(lhs, set, status); 5854 if (alloclhs==NULL) break; 5855 lhs=alloclhs; 5856 } 5857 if (rhs->digits>reqdigits) { /* [this only checks lostDigits] */ 5858 allocrhs=decRoundOperand(rhs, set, status); 5859 if (allocrhs==NULL) break; 5860 rhs=allocrhs; 5861 } 5862 } 5863 #endif 5864 /* [following code does not require input rounding] */ 5865 5866 /* Handle special values */ 5867 if (SPECIALARGS) { 5868 /* NaNs get usual processing */ 5869 if (SPECIALARGS & (DECSNAN | DECNAN)) 5870 decNaNs(res, lhs, rhs, set, status); 5871 /* one infinity but not both is bad */ 5872 else if ((lhs->bits ^ rhs->bits) & DECINF) 5873 *status|=DEC_Invalid_operation; 5874 /* both infinity: return lhs */ 5875 else uprv_decNumberCopy(res, lhs); /* [nop if in place] */ 5876 break; 5877 } 5878 5879 /* set requested exponent */ 5880 if (quant) reqexp=inrhs->exponent; /* quantize -- match exponents */ 5881 else { /* rescale -- use value of rhs */ 5882 /* Original rhs must be an integer that fits and is in range, */ 5883 /* which could be from -1999999997 to +999999999, thanks to */ 5884 /* subnormals */ 5885 reqexp=decGetInt(inrhs); /* [cannot fail] */ 5886 } 5887 5888 #if DECSUBSET 5889 if (!set->extended) etiny=set->emin; /* no subnormals */ 5890 #endif 5891 5892 if (reqexp==BADINT /* bad (rescale only) or .. */ 5893 || reqexp==BIGODD || reqexp==BIGEVEN /* very big (ditto) or .. */ 5894 || (reqexp<etiny) /* < lowest */ 5895 || (reqexp>set->emax)) { /* > emax */ 5896 *status|=DEC_Invalid_operation; 5897 break;} 5898 5899 /* the RHS has been processed, so it can be overwritten now if necessary */ 5900 if (ISZERO(lhs)) { /* zero coefficient unchanged */ 5901 uprv_decNumberCopy(res, lhs); /* [nop if in place] */ 5902 res->exponent=reqexp; /* .. just set exponent */ 5903 #if DECSUBSET 5904 if (!set->extended) res->bits=0; /* subset specification; no -0 */ 5905 #endif 5906 } 5907 else { /* non-zero lhs */ 5908 Int adjust=reqexp-lhs->exponent; /* digit adjustment needed */ 5909 /* if adjusted coefficient will definitely not fit, give up now */ 5910 if ((lhs->digits-adjust)>reqdigits) { 5911 *status|=DEC_Invalid_operation; 5912 break; 5913 } 5914 5915 if (adjust>0) { /* increasing exponent */ 5916 /* this will decrease the length of the coefficient by adjust */ 5917 /* digits, and must round as it does so */ 5918 decContext workset; /* work */ 5919 workset=*set; /* clone rounding, etc. */ 5920 workset.digits=lhs->digits-adjust; /* set requested length */ 5921 /* [note that the latter can be <1, here] */ 5922 decCopyFit(res, lhs, &workset, &residue, status); /* fit to result */ 5923 decApplyRound(res, &workset, residue, status); /* .. and round */ 5924 residue=0; /* [used] */ 5925 /* If just rounded a 999s case, exponent will be off by one; */ 5926 /* adjust back (after checking space), if so. */ 5927 if (res->exponent>reqexp) { 5928 /* re-check needed, e.g., for quantize(0.9999, 0.001) under */ 5929 /* set->digits==3 */ 5930 if (res->digits==reqdigits) { /* cannot shift by 1 */ 5931 *status&=~(DEC_Inexact | DEC_Rounded); /* [clean these] */ 5932 *status|=DEC_Invalid_operation; 5933 break; 5934 } 5935 res->digits=decShiftToMost(res->lsu, res->digits, 1); /* shift */ 5936 res->exponent--; /* (re)adjust the exponent. */ 5937 } 5938 #if DECSUBSET 5939 if (ISZERO(res) && !set->extended) res->bits=0; /* subset; no -0 */ 5940 #endif 5941 } /* increase */ 5942 else /* adjust<=0 */ { /* decreasing or = exponent */ 5943 /* this will increase the length of the coefficient by -adjust */ 5944 /* digits, by adding zero or more trailing zeros; this is */ 5945 /* already checked for fit, above */ 5946 uprv_decNumberCopy(res, lhs); /* [it will fit] */ 5947 /* if padding needed (adjust<0), add it now... */ 5948 if (adjust<0) { 5949 res->digits=decShiftToMost(res->lsu, res->digits, -adjust); 5950 res->exponent+=adjust; /* adjust the exponent */ 5951 } 5952 } /* decrease */ 5953 } /* non-zero */ 5954 5955 /* Check for overflow [do not use Finalize in this case, as an */ 5956 /* overflow here is a "don't fit" situation] */ 5957 if (res->exponent>set->emax-res->digits+1) { /* too big */ 5958 *status|=DEC_Invalid_operation; 5959 break; 5960 } 5961 else { 5962 decFinalize(res, set, &residue, status); /* set subnormal flags */ 5963 *status&=~DEC_Underflow; /* suppress Underflow [as per 754] */ 5964 } 5965 } while(0); /* end protected */ 5966 5967 #if DECSUBSET 5968 if (allocrhs!=NULL) free(allocrhs); /* drop any storage used */ 5969 if (alloclhs!=NULL) free(alloclhs); /* .. */ 5970 #endif 5971 return res; 5972 } /* decQuantizeOp */ 5973 5974 /* ------------------------------------------------------------------ */ 5975 /* decCompareOp -- compare, min, or max two Numbers */ 5976 /* */ 5977 /* This computes C = A ? B and carries out one of four operations: */ 5978 /* COMPARE -- returns the signum (as a number) giving the */ 5979 /* result of a comparison unless one or both */ 5980 /* operands is a NaN (in which case a NaN results) */ 5981 /* COMPSIG -- as COMPARE except that a quiet NaN raises */ 5982 /* Invalid operation. */ 5983 /* COMPMAX -- returns the larger of the operands, using the */ 5984 /* 754 maxnum operation */ 5985 /* COMPMAXMAG -- ditto, comparing absolute values */ 5986 /* COMPMIN -- the 754 minnum operation */ 5987 /* COMPMINMAG -- ditto, comparing absolute values */ 5988 /* COMTOTAL -- returns the signum (as a number) giving the */ 5989 /* result of a comparison using 754 total ordering */ 5990 /* */ 5991 /* res is C, the result. C may be A and/or B (e.g., X=X?X) */ 5992 /* lhs is A */ 5993 /* rhs is B */ 5994 /* set is the context */ 5995 /* op is the operation flag */ 5996 /* status is the usual accumulator */ 5997 /* */ 5998 /* C must have space for one digit for COMPARE or set->digits for */ 5999 /* COMPMAX, COMPMIN, COMPMAXMAG, or COMPMINMAG. */ 6000 /* ------------------------------------------------------------------ */ 6001 /* The emphasis here is on speed for common cases, and avoiding */ 6002 /* coefficient comparison if possible. */ 6003 /* ------------------------------------------------------------------ */ 6004 static decNumber * decCompareOp(decNumber *res, const decNumber *lhs, 6005 const decNumber *rhs, decContext *set, 6006 Flag op, uInt *status) { 6007 #if DECSUBSET 6008 decNumber *alloclhs=NULL; /* non-NULL if rounded lhs allocated */ 6009 decNumber *allocrhs=NULL; /* .., rhs */ 6010 #endif 6011 Int result=0; /* default result value */ 6012 uByte merged; /* work */ 6013 6014 #if DECCHECK 6015 if (decCheckOperands(res, lhs, rhs, set)) return res; 6016 #endif 6017 6018 do { /* protect allocated storage */ 6019 #if DECSUBSET 6020 if (!set->extended) { 6021 /* reduce operands and set lostDigits status, as needed */ 6022 if (lhs->digits>set->digits) { 6023 alloclhs=decRoundOperand(lhs, set, status); 6024 if (alloclhs==NULL) {result=BADINT; break;} 6025 lhs=alloclhs; 6026 } 6027 if (rhs->digits>set->digits) { 6028 allocrhs=decRoundOperand(rhs, set, status); 6029 if (allocrhs==NULL) {result=BADINT; break;} 6030 rhs=allocrhs; 6031 } 6032 } 6033 #endif 6034 /* [following code does not require input rounding] */ 6035 6036 /* If total ordering then handle differing signs 'up front' */ 6037 if (op==COMPTOTAL) { /* total ordering */ 6038 if (decNumberIsNegative(lhs) & !decNumberIsNegative(rhs)) { 6039 result=-1; 6040 break; 6041 } 6042 if (!decNumberIsNegative(lhs) & decNumberIsNegative(rhs)) { 6043 result=+1; 6044 break; 6045 } 6046 } 6047 6048 /* handle NaNs specially; let infinities drop through */ 6049 /* This assumes sNaN (even just one) leads to NaN. */ 6050 merged=(lhs->bits | rhs->bits) & (DECSNAN | DECNAN); 6051 if (merged) { /* a NaN bit set */ 6052 if (op==COMPARE); /* result will be NaN */ 6053 else if (op==COMPSIG) /* treat qNaN as sNaN */ 6054 *status|=DEC_Invalid_operation | DEC_sNaN; 6055 else if (op==COMPTOTAL) { /* total ordering, always finite */ 6056 /* signs are known to be the same; compute the ordering here */ 6057 /* as if the signs are both positive, then invert for negatives */ 6058 if (!decNumberIsNaN(lhs)) result=-1; 6059 else if (!decNumberIsNaN(rhs)) result=+1; 6060 /* here if both NaNs */ 6061 else if (decNumberIsSNaN(lhs) && decNumberIsQNaN(rhs)) result=-1; 6062 else if (decNumberIsQNaN(lhs) && decNumberIsSNaN(rhs)) result=+1; 6063 else { /* both NaN or both sNaN */ 6064 /* now it just depends on the payload */ 6065 result=decUnitCompare(lhs->lsu, D2U(lhs->digits), 6066 rhs->lsu, D2U(rhs->digits), 0); 6067 /* [Error not possible, as these are 'aligned'] */ 6068 } /* both same NaNs */ 6069 if (decNumberIsNegative(lhs)) result=-result; 6070 break; 6071 } /* total order */ 6072 6073 else if (merged & DECSNAN); /* sNaN -> qNaN */ 6074 else { /* here if MIN or MAX and one or two quiet NaNs */ 6075 /* min or max -- 754 rules ignore single NaN */ 6076 if (!decNumberIsNaN(lhs) || !decNumberIsNaN(rhs)) { 6077 /* just one NaN; force choice to be the non-NaN operand */ 6078 op=COMPMAX; 6079 if (lhs->bits & DECNAN) result=-1; /* pick rhs */ 6080 else result=+1; /* pick lhs */ 6081 break; 6082 } 6083 } /* max or min */ 6084 op=COMPNAN; /* use special path */ 6085 decNaNs(res, lhs, rhs, set, status); /* propagate NaN */ 6086 break; 6087 } 6088 /* have numbers */ 6089 if (op==COMPMAXMAG || op==COMPMINMAG) result=decCompare(lhs, rhs, 1); 6090 else result=decCompare(lhs, rhs, 0); /* sign matters */ 6091 } while(0); /* end protected */ 6092 6093 if (result==BADINT) *status|=DEC_Insufficient_storage; /* rare */ 6094 else { 6095 if (op==COMPARE || op==COMPSIG ||op==COMPTOTAL) { /* returning signum */ 6096 if (op==COMPTOTAL && result==0) { 6097 /* operands are numerically equal or same NaN (and same sign, */ 6098 /* tested first); if identical, leave result 0 */ 6099 if (lhs->exponent!=rhs->exponent) { 6100 if (lhs->exponent<rhs->exponent) result=-1; 6101 else result=+1; 6102 if (decNumberIsNegative(lhs)) result=-result; 6103 } /* lexp!=rexp */ 6104 } /* total-order by exponent */ 6105 uprv_decNumberZero(res); /* [always a valid result] */ 6106 if (result!=0) { /* must be -1 or +1 */ 6107 *res->lsu=1; 6108 if (result<0) res->bits=DECNEG; 6109 } 6110 } 6111 else if (op==COMPNAN); /* special, drop through */ 6112 else { /* MAX or MIN, non-NaN result */ 6113 Int residue=0; /* rounding accumulator */ 6114 /* choose the operand for the result */ 6115 const decNumber *choice; 6116 if (result==0) { /* operands are numerically equal */ 6117 /* choose according to sign then exponent (see 754) */ 6118 uByte slhs=(lhs->bits & DECNEG); 6119 uByte srhs=(rhs->bits & DECNEG); 6120 #if DECSUBSET 6121 if (!set->extended) { /* subset: force left-hand */ 6122 op=COMPMAX; 6123 result=+1; 6124 } 6125 else 6126 #endif 6127 if (slhs!=srhs) { /* signs differ */ 6128 if (slhs) result=-1; /* rhs is max */ 6129 else result=+1; /* lhs is max */ 6130 } 6131 else if (slhs && srhs) { /* both negative */ 6132 if (lhs->exponent<rhs->exponent) result=+1; 6133 else result=-1; 6134 /* [if equal, use lhs, technically identical] */ 6135 } 6136 else { /* both positive */ 6137 if (lhs->exponent>rhs->exponent) result=+1; 6138 else result=-1; 6139 /* [ditto] */ 6140 } 6141 } /* numerically equal */ 6142 /* here result will be non-0; reverse if looking for MIN */ 6143 if (op==COMPMIN || op==COMPMINMAG) result=-result; 6144 choice=(result>0 ? lhs : rhs); /* choose */ 6145 /* copy chosen to result, rounding if need be */ 6146 decCopyFit(res, choice, set, &residue, status); 6147 decFinish(res, set, &residue, status); 6148 } 6149 } 6150 #if DECSUBSET 6151 if (allocrhs!=NULL) free(allocrhs); /* free any storage used */ 6152 if (alloclhs!=NULL) free(alloclhs); /* .. */ 6153 #endif 6154 return res; 6155 } /* decCompareOp */ 6156 6157 /* ------------------------------------------------------------------ */ 6158 /* decCompare -- compare two decNumbers by numerical value */ 6159 /* */ 6160 /* This routine compares A ? B without altering them. */ 6161 /* */ 6162 /* Arg1 is A, a decNumber which is not a NaN */ 6163 /* Arg2 is B, a decNumber which is not a NaN */ 6164 /* Arg3 is 1 for a sign-independent compare, 0 otherwise */ 6165 /* */ 6166 /* returns -1, 0, or 1 for A<B, A==B, or A>B, or BADINT if failure */ 6167 /* (the only possible failure is an allocation error) */ 6168 /* ------------------------------------------------------------------ */ 6169 static Int decCompare(const decNumber *lhs, const decNumber *rhs, 6170 Flag abs_c) { 6171 Int result; /* result value */ 6172 Int sigr; /* rhs signum */ 6173 Int compare; /* work */ 6174 6175 result=1; /* assume signum(lhs) */ 6176 if (ISZERO(lhs)) result=0; 6177 if (abs_c) { 6178 if (ISZERO(rhs)) return result; /* LHS wins or both 0 */ 6179 /* RHS is non-zero */ 6180 if (result==0) return -1; /* LHS is 0; RHS wins */ 6181 /* [here, both non-zero, result=1] */ 6182 } 6183 else { /* signs matter */ 6184 if (result && decNumberIsNegative(lhs)) result=-1; 6185 sigr=1; /* compute signum(rhs) */ 6186 if (ISZERO(rhs)) sigr=0; 6187 else if (decNumberIsNegative(rhs)) sigr=-1; 6188 if (result > sigr) return +1; /* L > R, return 1 */ 6189 if (result < sigr) return -1; /* L < R, return -1 */ 6190 if (result==0) return 0; /* both 0 */ 6191 } 6192 6193 /* signums are the same; both are non-zero */ 6194 if ((lhs->bits | rhs->bits) & DECINF) { /* one or more infinities */ 6195 if (decNumberIsInfinite(rhs)) { 6196 if (decNumberIsInfinite(lhs)) result=0;/* both infinite */ 6197 else result=-result; /* only rhs infinite */ 6198 } 6199 return result; 6200 } 6201 /* must compare the coefficients, allowing for exponents */ 6202 if (lhs->exponent>rhs->exponent) { /* LHS exponent larger */ 6203 /* swap sides, and sign */ 6204 const decNumber *temp=lhs; 6205 lhs=rhs; 6206 rhs=temp; 6207 result=-result; 6208 } 6209 compare=decUnitCompare(lhs->lsu, D2U(lhs->digits), 6210 rhs->lsu, D2U(rhs->digits), 6211 rhs->exponent-lhs->exponent); 6212 if (compare!=BADINT) compare*=result; /* comparison succeeded */ 6213 return compare; 6214 } /* decCompare */ 6215 6216 /* ------------------------------------------------------------------ */ 6217 /* decUnitCompare -- compare two >=0 integers in Unit arrays */ 6218 /* */ 6219 /* This routine compares A ? B*10**E where A and B are unit arrays */ 6220 /* A is a plain integer */ 6221 /* B has an exponent of E (which must be non-negative) */ 6222 /* */ 6223 /* Arg1 is A first Unit (lsu) */ 6224 /* Arg2 is A length in Units */ 6225 /* Arg3 is B first Unit (lsu) */ 6226 /* Arg4 is B length in Units */ 6227 /* Arg5 is E (0 if the units are aligned) */ 6228 /* */ 6229 /* returns -1, 0, or 1 for A<B, A==B, or A>B, or BADINT if failure */ 6230 /* (the only possible failure is an allocation error, which can */ 6231 /* only occur if E!=0) */ 6232 /* ------------------------------------------------------------------ */ 6233 static Int decUnitCompare(const Unit *a, Int alength, 6234 const Unit *b, Int blength, Int exp) { 6235 Unit *acc; /* accumulator for result */ 6236 Unit accbuff[SD2U(DECBUFFER*2+1)]; /* local buffer */ 6237 Unit *allocacc=NULL; /* -> allocated acc buffer, iff allocated */ 6238 Int accunits, need; /* units in use or needed for acc */ 6239 const Unit *l, *r, *u; /* work */ 6240 Int expunits, exprem, result; /* .. */ 6241 6242 if (exp==0) { /* aligned; fastpath */ 6243 if (alength>blength) return 1; 6244 if (alength<blength) return -1; 6245 /* same number of units in both -- need unit-by-unit compare */ 6246 l=a+alength-1; 6247 r=b+alength-1; 6248 for (;l>=a; l--, r--) { 6249 if (*l>*r) return 1; 6250 if (*l<*r) return -1; 6251 } 6252 return 0; /* all units match */ 6253 } /* aligned */ 6254 6255 /* Unaligned. If one is >1 unit longer than the other, padded */ 6256 /* approximately, then can return easily */ 6257 if (alength>blength+(Int)D2U(exp)) return 1; 6258 if (alength+1<blength+(Int)D2U(exp)) return -1; 6259 6260 /* Need to do a real subtract. For this, a result buffer is needed */ 6261 /* even though only the sign is of interest. Its length needs */ 6262 /* to be the larger of alength and padded blength, +2 */ 6263 need=blength+D2U(exp); /* maximum real length of B */ 6264 if (need<alength) need=alength; 6265 need+=2; 6266 acc=accbuff; /* assume use local buffer */ 6267 if (need*sizeof(Unit)>sizeof(accbuff)) { 6268 allocacc=(Unit *)malloc(need*sizeof(Unit)); 6269 if (allocacc==NULL) return BADINT; /* hopeless -- abandon */ 6270 acc=allocacc; 6271 } 6272 /* Calculate units and remainder from exponent. */ 6273 expunits=exp/DECDPUN; 6274 exprem=exp%DECDPUN; 6275 /* subtract [A+B*(-m)] */ 6276 accunits=decUnitAddSub(a, alength, b, blength, expunits, acc, 6277 -(Int)powers[exprem]); 6278 /* [UnitAddSub result may have leading zeros, even on zero] */ 6279 if (accunits<0) result=-1; /* negative result */ 6280 else { /* non-negative result */ 6281 /* check units of the result before freeing any storage */ 6282 for (u=acc; u<acc+accunits-1 && *u==0;) u++; 6283 result=(*u==0 ? 0 : +1); 6284 } 6285 /* clean up and return the result */ 6286 if (allocacc!=NULL) free(allocacc); /* drop any storage used */ 6287 return result; 6288 } /* decUnitCompare */ 6289 6290 /* ------------------------------------------------------------------ */ 6291 /* decUnitAddSub -- add or subtract two >=0 integers in Unit arrays */ 6292 /* */ 6293 /* This routine performs the calculation: */ 6294 /* */ 6295 /* C=A+(B*M) */ 6296 /* */ 6297 /* Where M is in the range -DECDPUNMAX through +DECDPUNMAX. */ 6298 /* */ 6299 /* A may be shorter or longer than B. */ 6300 /* */ 6301 /* Leading zeros are not removed after a calculation. The result is */ 6302 /* either the same length as the longer of A and B (adding any */ 6303 /* shift), or one Unit longer than that (if a Unit carry occurred). */ 6304 /* */ 6305 /* A and B content are not altered unless C is also A or B. */ 6306 /* C may be the same array as A or B, but only if no zero padding is */ 6307 /* requested (that is, C may be B only if bshift==0). */ 6308 /* C is filled from the lsu; only those units necessary to complete */ 6309 /* the calculation are referenced. */ 6310 /* */ 6311 /* Arg1 is A first Unit (lsu) */ 6312 /* Arg2 is A length in Units */ 6313 /* Arg3 is B first Unit (lsu) */ 6314 /* Arg4 is B length in Units */ 6315 /* Arg5 is B shift in Units (>=0; pads with 0 units if positive) */ 6316 /* Arg6 is C first Unit (lsu) */ 6317 /* Arg7 is M, the multiplier */ 6318 /* */ 6319 /* returns the count of Units written to C, which will be non-zero */ 6320 /* and negated if the result is negative. That is, the sign of the */ 6321 /* returned Int is the sign of the result (positive for zero) and */ 6322 /* the absolute value of the Int is the count of Units. */ 6323 /* */ 6324 /* It is the caller's responsibility to make sure that C size is */ 6325 /* safe, allowing space if necessary for a one-Unit carry. */ 6326 /* */ 6327 /* This routine is severely performance-critical; *any* change here */ 6328 /* must be measured (timed) to assure no performance degradation. */ 6329 /* In particular, trickery here tends to be counter-productive, as */ 6330 /* increased complexity of code hurts register optimizations on */ 6331 /* register-poor architectures. Avoiding divisions is nearly */ 6332 /* always a Good Idea, however. */ 6333 /* */ 6334 /* Special thanks to Rick McGuire (IBM Cambridge, MA) and Dave Clark */ 6335 /* (IBM Warwick, UK) for some of the ideas used in this routine. */ 6336 /* ------------------------------------------------------------------ */ 6337 static Int decUnitAddSub(const Unit *a, Int alength, 6338 const Unit *b, Int blength, Int bshift, 6339 Unit *c, Int m) { 6340 const Unit *alsu=a; /* A lsu [need to remember it] */ 6341 Unit *clsu=c; /* C ditto */ 6342 Unit *minC; /* low water mark for C */ 6343 Unit *maxC; /* high water mark for C */ 6344 eInt carry=0; /* carry integer (could be Long) */ 6345 Int add; /* work */ 6346 #if DECDPUN<=4 /* myriadal, millenary, etc. */ 6347 Int est; /* estimated quotient */ 6348 #endif 6349 6350 #if DECTRACE 6351 if (alength<1 || blength<1) 6352 printf("decUnitAddSub: alen blen m %ld %ld [%ld]\n", alength, blength, m); 6353 #endif 6354 6355 maxC=c+alength; /* A is usually the longer */ 6356 minC=c+blength; /* .. and B the shorter */ 6357 if (bshift!=0) { /* B is shifted; low As copy across */ 6358 minC+=bshift; 6359 /* if in place [common], skip copy unless there's a gap [rare] */ 6360 if (a==c && bshift<=alength) { 6361 c+=bshift; 6362 a+=bshift; 6363 } 6364 else for (; c<clsu+bshift; a++, c++) { /* copy needed */ 6365 if (a<alsu+alength) *c=*a; 6366 else *c=0; 6367 } 6368 } 6369 if (minC>maxC) { /* swap */ 6370 Unit *hold=minC; 6371 minC=maxC; 6372 maxC=hold; 6373 } 6374 6375 /* For speed, do the addition as two loops; the first where both A */ 6376 /* and B contribute, and the second (if necessary) where only one or */ 6377 /* other of the numbers contribute. */ 6378 /* Carry handling is the same (i.e., duplicated) in each case. */ 6379 for (; c<minC; c++) { 6380 carry+=*a; 6381 a++; 6382 carry+=((eInt)*b)*m; /* [special-casing m=1/-1 */ 6383 b++; /* here is not a win] */ 6384 /* here carry is new Unit of digits; it could be +ve or -ve */ 6385 if ((ueInt)carry<=DECDPUNMAX) { /* fastpath 0-DECDPUNMAX */ 6386 *c=(Unit)carry; 6387 carry=0; 6388 continue; 6389 } 6390 #if DECDPUN==4 /* use divide-by-multiply */ 6391 if (carry>=0) { 6392 est=(((ueInt)carry>>11)*53687)>>18; 6393 *c=(Unit)(carry-est*(DECDPUNMAX+1)); /* remainder */ 6394 carry=est; /* likely quotient [89%] */ 6395 if (*c<DECDPUNMAX+1) continue; /* estimate was correct */ 6396 carry++; 6397 *c-=DECDPUNMAX+1; 6398 continue; 6399 } 6400 /* negative case */ 6401 carry=carry+(eInt)(DECDPUNMAX+1)*(DECDPUNMAX+1); /* make positive */ 6402 est=(((ueInt)carry>>11)*53687)>>18; 6403 *c=(Unit)(carry-est*(DECDPUNMAX+1)); 6404 carry=est-(DECDPUNMAX+1); /* correctly negative */ 6405 if (*c<DECDPUNMAX+1) continue; /* was OK */ 6406 carry++; 6407 *c-=DECDPUNMAX+1; 6408 #elif DECDPUN==3 6409 if (carry>=0) { 6410 est=(((ueInt)carry>>3)*16777)>>21; 6411 *c=(Unit)(carry-est*(DECDPUNMAX+1)); /* remainder */ 6412 carry=est; /* likely quotient [99%] */ 6413 if (*c<DECDPUNMAX+1) continue; /* estimate was correct */ 6414 carry++; 6415 *c-=DECDPUNMAX+1; 6416 continue; 6417 } 6418 /* negative case */ 6419 carry=carry+(eInt)(DECDPUNMAX+1)*(DECDPUNMAX+1); /* make positive */ 6420 est=(((ueInt)carry>>3)*16777)>>21; 6421 *c=(Unit)(carry-est*(DECDPUNMAX+1)); 6422 carry=est-(DECDPUNMAX+1); /* correctly negative */ 6423 if (*c<DECDPUNMAX+1) continue; /* was OK */ 6424 carry++; 6425 *c-=DECDPUNMAX+1; 6426 #elif DECDPUN<=2 6427 /* Can use QUOT10 as carry <= 4 digits */ 6428 if (carry>=0) { 6429 est=QUOT10(carry, DECDPUN); 6430 *c=(Unit)(carry-est*(DECDPUNMAX+1)); /* remainder */ 6431 carry=est; /* quotient */ 6432 continue; 6433 } 6434 /* negative case */ 6435 carry=carry+(eInt)(DECDPUNMAX+1)*(DECDPUNMAX+1); /* make positive */ 6436 est=QUOT10(carry, DECDPUN); 6437 *c=(Unit)(carry-est*(DECDPUNMAX+1)); 6438 carry=est-(DECDPUNMAX+1); /* correctly negative */ 6439 #else 6440 /* remainder operator is undefined if negative, so must test */ 6441 if ((ueInt)carry<(DECDPUNMAX+1)*2) { /* fastpath carry +1 */ 6442 *c=(Unit)(carry-(DECDPUNMAX+1)); /* [helps additions] */ 6443 carry=1; 6444 continue; 6445 } 6446 if (carry>=0) { 6447 *c=(Unit)(carry%(DECDPUNMAX+1)); 6448 carry=carry/(DECDPUNMAX+1); 6449 continue; 6450 } 6451 /* negative case */ 6452 carry=carry+(eInt)(DECDPUNMAX+1)*(DECDPUNMAX+1); /* make positive */ 6453 *c=(Unit)(carry%(DECDPUNMAX+1)); 6454 carry=carry/(DECDPUNMAX+1)-(DECDPUNMAX+1); 6455 #endif 6456 } /* c */ 6457 6458 /* now may have one or other to complete */ 6459 /* [pretest to avoid loop setup/shutdown] */ 6460 if (c<maxC) for (; c<maxC; c++) { 6461 if (a<alsu+alength) { /* still in A */ 6462 carry+=*a; 6463 a++; 6464 } 6465 else { /* inside B */ 6466 carry+=((eInt)*b)*m; 6467 b++; 6468 } 6469 /* here carry is new Unit of digits; it could be +ve or -ve and */ 6470 /* magnitude up to DECDPUNMAX squared */ 6471 if ((ueInt)carry<=DECDPUNMAX) { /* fastpath 0-DECDPUNMAX */ 6472 *c=(Unit)carry; 6473 carry=0; 6474 continue; 6475 } 6476 /* result for this unit is negative or >DECDPUNMAX */ 6477 #if DECDPUN==4 /* use divide-by-multiply */ 6478 if (carry>=0) { 6479 est=(((ueInt)carry>>11)*53687)>>18; 6480 *c=(Unit)(carry-est*(DECDPUNMAX+1)); /* remainder */ 6481 carry=est; /* likely quotient [79.7%] */ 6482 if (*c<DECDPUNMAX+1) continue; /* estimate was correct */ 6483 carry++; 6484 *c-=DECDPUNMAX+1; 6485 continue; 6486 } 6487 /* negative case */ 6488 carry=carry+(eInt)(DECDPUNMAX+1)*(DECDPUNMAX+1); /* make positive */ 6489 est=(((ueInt)carry>>11)*53687)>>18; 6490 *c=(Unit)(carry-est*(DECDPUNMAX+1)); 6491 carry=est-(DECDPUNMAX+1); /* correctly negative */ 6492 if (*c<DECDPUNMAX+1) continue; /* was OK */ 6493 carry++; 6494 *c-=DECDPUNMAX+1; 6495 #elif DECDPUN==3 6496 if (carry>=0) { 6497 est=(((ueInt)carry>>3)*16777)>>21; 6498 *c=(Unit)(carry-est*(DECDPUNMAX+1)); /* remainder */ 6499 carry=est; /* likely quotient [99%] */ 6500 if (*c<DECDPUNMAX+1) continue; /* estimate was correct */ 6501 carry++; 6502 *c-=DECDPUNMAX+1; 6503 continue; 6504 } 6505 /* negative case */ 6506 carry=carry+(eInt)(DECDPUNMAX+1)*(DECDPUNMAX+1); /* make positive */ 6507 est=(((ueInt)carry>>3)*16777)>>21; 6508 *c=(Unit)(carry-est*(DECDPUNMAX+1)); 6509 carry=est-(DECDPUNMAX+1); /* correctly negative */ 6510 if (*c<DECDPUNMAX+1) continue; /* was OK */ 6511 carry++; 6512 *c-=DECDPUNMAX+1; 6513 #elif DECDPUN<=2 6514 if (carry>=0) { 6515 est=QUOT10(carry, DECDPUN); 6516 *c=(Unit)(carry-est*(DECDPUNMAX+1)); /* remainder */ 6517 carry=est; /* quotient */ 6518 continue; 6519 } 6520 /* negative case */ 6521 carry=carry+(eInt)(DECDPUNMAX+1)*(DECDPUNMAX+1); /* make positive */ 6522 est=QUOT10(carry, DECDPUN); 6523 *c=(Unit)(carry-est*(DECDPUNMAX+1)); 6524 carry=est-(DECDPUNMAX+1); /* correctly negative */ 6525 #else 6526 if ((ueInt)carry<(DECDPUNMAX+1)*2){ /* fastpath carry 1 */ 6527 *c=(Unit)(carry-(DECDPUNMAX+1)); 6528 carry=1; 6529 continue; 6530 } 6531 /* remainder operator is undefined if negative, so must test */ 6532 if (carry>=0) { 6533 *c=(Unit)(carry%(DECDPUNMAX+1)); 6534 carry=carry/(DECDPUNMAX+1); 6535 continue; 6536 } 6537 /* negative case */ 6538 carry=carry+(eInt)(DECDPUNMAX+1)*(DECDPUNMAX+1); /* make positive */ 6539 *c=(Unit)(carry%(DECDPUNMAX+1)); 6540 carry=carry/(DECDPUNMAX+1)-(DECDPUNMAX+1); 6541 #endif 6542 } /* c */ 6543 6544 /* OK, all A and B processed; might still have carry or borrow */ 6545 /* return number of Units in the result, negated if a borrow */ 6546 if (carry==0) return c-clsu; /* no carry, so no more to do */ 6547 if (carry>0) { /* positive carry */ 6548 *c=(Unit)carry; /* place as new unit */ 6549 c++; /* .. */ 6550 return c-clsu; 6551 } 6552 /* -ve carry: it's a borrow; complement needed */ 6553 add=1; /* temporary carry... */ 6554 for (c=clsu; c<maxC; c++) { 6555 add=DECDPUNMAX+add-*c; 6556 if (add<=DECDPUNMAX) { 6557 *c=(Unit)add; 6558 add=0; 6559 } 6560 else { 6561 *c=0; 6562 add=1; 6563 } 6564 } 6565 /* add an extra unit iff it would be non-zero */ 6566 #if DECTRACE 6567 printf("UAS borrow: add %ld, carry %ld\n", add, carry); 6568 #endif 6569 if ((add-carry-1)!=0) { 6570 *c=(Unit)(add-carry-1); 6571 c++; /* interesting, include it */ 6572 } 6573 return clsu-c; /* -ve result indicates borrowed */ 6574 } /* decUnitAddSub */ 6575 6576 /* ------------------------------------------------------------------ */ 6577 /* decTrim -- trim trailing zeros or normalize */ 6578 /* */ 6579 /* dn is the number to trim or normalize */ 6580 /* set is the context to use to check for clamp */ 6581 /* all is 1 to remove all trailing zeros, 0 for just fraction ones */ 6582 /* noclamp is 1 to unconditional (unclamped) trim */ 6583 /* dropped returns the number of discarded trailing zeros */ 6584 /* returns dn */ 6585 /* */ 6586 /* If clamp is set in the context then the number of zeros trimmed */ 6587 /* may be limited if the exponent is high. */ 6588 /* All fields are updated as required. This is a utility operation, */ 6589 /* so special values are unchanged and no error is possible. */ 6590 /* ------------------------------------------------------------------ */ 6591 static decNumber * decTrim(decNumber *dn, decContext *set, Flag all, 6592 Flag noclamp, Int *dropped) { 6593 Int d, exp; /* work */ 6594 uInt cut; /* .. */ 6595 Unit *up; /* -> current Unit */ 6596 6597 #if DECCHECK 6598 if (decCheckOperands(dn, DECUNUSED, DECUNUSED, DECUNCONT)) return dn; 6599 #endif 6600 6601 *dropped=0; /* assume no zeros dropped */ 6602 if ((dn->bits & DECSPECIAL) /* fast exit if special .. */ 6603 || (*dn->lsu & 0x01)) return dn; /* .. or odd */ 6604 if (ISZERO(dn)) { /* .. or 0 */ 6605 dn->exponent=0; /* (sign is preserved) */ 6606 return dn; 6607 } 6608 6609 /* have a finite number which is even */ 6610 exp=dn->exponent; 6611 cut=1; /* digit (1-DECDPUN) in Unit */ 6612 up=dn->lsu; /* -> current Unit */ 6613 for (d=0; d<dn->digits-1; d++) { /* [don't strip the final digit] */ 6614 /* slice by powers */ 6615 #if DECDPUN<=4 6616 uInt quot=QUOT10(*up, cut); 6617 if ((*up-quot*powers[cut])!=0) break; /* found non-0 digit */ 6618 #else 6619 if (*up%powers[cut]!=0) break; /* found non-0 digit */ 6620 #endif 6621 /* have a trailing 0 */ 6622 if (!all) { /* trimming */ 6623 /* [if exp>0 then all trailing 0s are significant for trim] */ 6624 if (exp<=0) { /* if digit might be significant */ 6625 if (exp==0) break; /* then quit */ 6626 exp++; /* next digit might be significant */ 6627 } 6628 } 6629 cut++; /* next power */ 6630 if (cut>DECDPUN) { /* need new Unit */ 6631 up++; 6632 cut=1; 6633 } 6634 } /* d */ 6635 if (d==0) return dn; /* none to drop */ 6636 6637 /* may need to limit drop if clamping */ 6638 if (set->clamp && !noclamp) { 6639 Int maxd=set->emax-set->digits+1-dn->exponent; 6640 if (maxd<=0) return dn; /* nothing possible */ 6641 if (d>maxd) d=maxd; 6642 } 6643 6644 /* effect the drop */ 6645 decShiftToLeast(dn->lsu, D2U(dn->digits), d); 6646 dn->exponent+=d; /* maintain numerical value */ 6647 dn->digits-=d; /* new length */ 6648 *dropped=d; /* report the count */ 6649 return dn; 6650 } /* decTrim */ 6651 6652 /* ------------------------------------------------------------------ */ 6653 /* decReverse -- reverse a Unit array in place */ 6654 /* */ 6655 /* ulo is the start of the array */ 6656 /* uhi is the end of the array (highest Unit to include) */ 6657 /* */ 6658 /* The units ulo through uhi are reversed in place (if the number */ 6659 /* of units is odd, the middle one is untouched). Note that the */ 6660 /* digit(s) in each unit are unaffected. */ 6661 /* ------------------------------------------------------------------ */ 6662 static void decReverse(Unit *ulo, Unit *uhi) { 6663 Unit temp; 6664 for (; ulo<uhi; ulo++, uhi--) { 6665 temp=*ulo; 6666 *ulo=*uhi; 6667 *uhi=temp; 6668 } 6669 return; 6670 } /* decReverse */ 6671 6672 /* ------------------------------------------------------------------ */ 6673 /* decShiftToMost -- shift digits in array towards most significant */ 6674 /* */ 6675 /* uar is the array */ 6676 /* digits is the count of digits in use in the array */ 6677 /* shift is the number of zeros to pad with (least significant); */ 6678 /* it must be zero or positive */ 6679 /* */ 6680 /* returns the new length of the integer in the array, in digits */ 6681 /* */ 6682 /* No overflow is permitted (that is, the uar array must be known to */ 6683 /* be large enough to hold the result, after shifting). */ 6684 /* ------------------------------------------------------------------ */ 6685 static Int decShiftToMost(Unit *uar, Int digits, Int shift) { 6686 Unit *target, *source, *first; /* work */ 6687 Int cut; /* odd 0's to add */ 6688 uInt next; /* work */ 6689 6690 if (shift==0) return digits; /* [fastpath] nothing to do */ 6691 if ((digits+shift)<=DECDPUN) { /* [fastpath] single-unit case */ 6692 *uar=(Unit)(*uar*powers[shift]); 6693 return digits+shift; 6694 } 6695 6696 next=0; /* all paths */ 6697 source=uar+D2U(digits)-1; /* where msu comes from */ 6698 target=source+D2U(shift); /* where upper part of first cut goes */ 6699 cut=DECDPUN-MSUDIGITS(shift); /* where to slice */ 6700 if (cut==0) { /* unit-boundary case */ 6701 for (; source>=uar; source--, target--) *target=*source; 6702 } 6703 else { 6704 first=uar+D2U(digits+shift)-1; /* where msu of source will end up */ 6705 for (; source>=uar; source--, target--) { 6706 /* split the source Unit and accumulate remainder for next */ 6707 #if DECDPUN<=4 6708 uInt quot=QUOT10(*source, cut); 6709 uInt rem=*source-quot*powers[cut]; 6710 next+=quot; 6711 #else 6712 uInt rem=*source%powers[cut]; 6713 next+=*source/powers[cut]; 6714 #endif 6715 if (target<=first) *target=(Unit)next; /* write to target iff valid */ 6716 next=rem*powers[DECDPUN-cut]; /* save remainder for next Unit */ 6717 } 6718 } /* shift-move */ 6719 6720 /* propagate any partial unit to one below and clear the rest */ 6721 for (; target>=uar; target--) { 6722 *target=(Unit)next; 6723 next=0; 6724 } 6725 return digits+shift; 6726 } /* decShiftToMost */ 6727 6728 /* ------------------------------------------------------------------ */ 6729 /* decShiftToLeast -- shift digits in array towards least significant */ 6730 /* */ 6731 /* uar is the array */ 6732 /* units is length of the array, in units */ 6733 /* shift is the number of digits to remove from the lsu end; it */ 6734 /* must be zero or positive and <= than units*DECDPUN. */ 6735 /* */ 6736 /* returns the new length of the integer in the array, in units */ 6737 /* */ 6738 /* Removed digits are discarded (lost). Units not required to hold */ 6739 /* the final result are unchanged. */ 6740 /* ------------------------------------------------------------------ */ 6741 static Int decShiftToLeast(Unit *uar, Int units, Int shift) { 6742 Unit *target, *up; /* work */ 6743 Int cut, count; /* work */ 6744 Int quot, rem; /* for division */ 6745 6746 if (shift==0) return units; /* [fastpath] nothing to do */ 6747 if (shift==units*DECDPUN) { /* [fastpath] little to do */ 6748 *uar=0; /* all digits cleared gives zero */ 6749 return 1; /* leaves just the one */ 6750 } 6751 6752 target=uar; /* both paths */ 6753 cut=MSUDIGITS(shift); 6754 if (cut==DECDPUN) { /* unit-boundary case; easy */ 6755 up=uar+D2U(shift); 6756 for (; up<uar+units; target++, up++) *target=*up; 6757 return target-uar; 6758 } 6759 6760 /* messier */ 6761 up=uar+D2U(shift-cut); /* source; correct to whole Units */ 6762 count=units*DECDPUN-shift; /* the maximum new length */ 6763 #if DECDPUN<=4 6764 quot=QUOT10(*up, cut); 6765 #else 6766 quot=*up/powers[cut]; 6767 #endif 6768 for (; ; target++) { 6769 *target=(Unit)quot; 6770 count-=(DECDPUN-cut); 6771 if (count<=0) break; 6772 up++; 6773 quot=*up; 6774 #if DECDPUN<=4 6775 quot=QUOT10(quot, cut); 6776 rem=*up-quot*powers[cut]; 6777 #else 6778 rem=quot%powers[cut]; 6779 quot=quot/powers[cut]; 6780 #endif 6781 *target=(Unit)(*target+rem*powers[DECDPUN-cut]); 6782 count-=cut; 6783 if (count<=0) break; 6784 } 6785 return target-uar+1; 6786 } /* decShiftToLeast */ 6787 6788 #if DECSUBSET 6789 /* ------------------------------------------------------------------ */ 6790 /* decRoundOperand -- round an operand [used for subset only] */ 6791 /* */ 6792 /* dn is the number to round (dn->digits is > set->digits) */ 6793 /* set is the relevant context */ 6794 /* status is the status accumulator */ 6795 /* */ 6796 /* returns an allocated decNumber with the rounded result. */ 6797 /* */ 6798 /* lostDigits and other status may be set by this. */ 6799 /* */ 6800 /* Since the input is an operand, it must not be modified. */ 6801 /* Instead, return an allocated decNumber, rounded as required. */ 6802 /* It is the caller's responsibility to free the allocated storage. */ 6803 /* */ 6804 /* If no storage is available then the result cannot be used, so NULL */ 6805 /* is returned. */ 6806 /* ------------------------------------------------------------------ */ 6807 static decNumber *decRoundOperand(const decNumber *dn, decContext *set, 6808 uInt *status) { 6809 decNumber *res; /* result structure */ 6810 uInt newstatus=0; /* status from round */ 6811 Int residue=0; /* rounding accumulator */ 6812 6813 /* Allocate storage for the returned decNumber, big enough for the */ 6814 /* length specified by the context */ 6815 res=(decNumber *)malloc(sizeof(decNumber) 6816 +(D2U(set->digits)-1)*sizeof(Unit)); 6817 if (res==NULL) { 6818 *status|=DEC_Insufficient_storage; 6819 return NULL; 6820 } 6821 decCopyFit(res, dn, set, &residue, &newstatus); 6822 decApplyRound(res, set, residue, &newstatus); 6823 6824 /* If that set Inexact then "lost digits" is raised... */ 6825 if (newstatus & DEC_Inexact) newstatus|=DEC_Lost_digits; 6826 *status|=newstatus; 6827 return res; 6828 } /* decRoundOperand */ 6829 #endif 6830 6831 /* ------------------------------------------------------------------ */ 6832 /* decCopyFit -- copy a number, truncating the coefficient if needed */ 6833 /* */ 6834 /* dest is the target decNumber */ 6835 /* src is the source decNumber */ 6836 /* set is the context [used for length (digits) and rounding mode] */ 6837 /* residue is the residue accumulator */ 6838 /* status contains the current status to be updated */ 6839 /* */ 6840 /* (dest==src is allowed and will be a no-op if fits) */ 6841 /* All fields are updated as required. */ 6842 /* ------------------------------------------------------------------ */ 6843 static void decCopyFit(decNumber *dest, const decNumber *src, 6844 decContext *set, Int *residue, uInt *status) { 6845 dest->bits=src->bits; 6846 dest->exponent=src->exponent; 6847 decSetCoeff(dest, set, src->lsu, src->digits, residue, status); 6848 } /* decCopyFit */ 6849 6850 /* ------------------------------------------------------------------ */ 6851 /* decSetCoeff -- set the coefficient of a number */ 6852 /* */ 6853 /* dn is the number whose coefficient array is to be set. */ 6854 /* It must have space for set->digits digits */ 6855 /* set is the context [for size] */ 6856 /* lsu -> lsu of the source coefficient [may be dn->lsu] */ 6857 /* len is digits in the source coefficient [may be dn->digits] */ 6858 /* residue is the residue accumulator. This has values as in */ 6859 /* decApplyRound, and will be unchanged unless the */ 6860 /* target size is less than len. In this case, the */ 6861 /* coefficient is truncated and the residue is updated to */ 6862 /* reflect the previous residue and the dropped digits. */ 6863 /* status is the status accumulator, as usual */ 6864 /* */ 6865 /* The coefficient may already be in the number, or it can be an */ 6866 /* external intermediate array. If it is in the number, lsu must == */ 6867 /* dn->lsu and len must == dn->digits. */ 6868 /* */ 6869 /* Note that the coefficient length (len) may be < set->digits, and */ 6870 /* in this case this merely copies the coefficient (or is a no-op */ 6871 /* if dn->lsu==lsu). */ 6872 /* */ 6873 /* Note also that (only internally, from decQuantizeOp and */ 6874 /* decSetSubnormal) the value of set->digits may be less than one, */ 6875 /* indicating a round to left. This routine handles that case */ 6876 /* correctly; caller ensures space. */ 6877 /* */ 6878 /* dn->digits, dn->lsu (and as required), and dn->exponent are */ 6879 /* updated as necessary. dn->bits (sign) is unchanged. */ 6880 /* */ 6881 /* DEC_Rounded status is set if any digits are discarded. */ 6882 /* DEC_Inexact status is set if any non-zero digits are discarded, or */ 6883 /* incoming residue was non-0 (implies rounded) */ 6884 /* ------------------------------------------------------------------ */ 6885 /* mapping array: maps 0-9 to canonical residues, so that a residue */ 6886 /* can be adjusted in the range [-1, +1] and achieve correct rounding */ 6887 /* 0 1 2 3 4 5 6 7 8 9 */ 6888 static const uByte resmap[10]={0, 3, 3, 3, 3, 5, 7, 7, 7, 7}; 6889 static void decSetCoeff(decNumber *dn, decContext *set, const Unit *lsu, 6890 Int len, Int *residue, uInt *status) { 6891 Int discard; /* number of digits to discard */ 6892 uInt cut; /* cut point in Unit */ 6893 const Unit *up; /* work */ 6894 Unit *target; /* .. */ 6895 Int count; /* .. */ 6896 #if DECDPUN<=4 6897 uInt temp; /* .. */ 6898 #endif 6899 6900 discard=len-set->digits; /* digits to discard */ 6901 if (discard<=0) { /* no digits are being discarded */ 6902 if (dn->lsu!=lsu) { /* copy needed */ 6903 /* copy the coefficient array to the result number; no shift needed */ 6904 count=len; /* avoids D2U */ 6905 up=lsu; 6906 for (target=dn->lsu; count>0; target++, up++, count-=DECDPUN) 6907 *target=*up; 6908 dn->digits=len; /* set the new length */ 6909 } 6910 /* dn->exponent and residue are unchanged, record any inexactitude */ 6911 if (*residue!=0) *status|=(DEC_Inexact | DEC_Rounded); 6912 return; 6913 } 6914 6915 /* some digits must be discarded ... */ 6916 dn->exponent+=discard; /* maintain numerical value */ 6917 *status|=DEC_Rounded; /* accumulate Rounded status */ 6918 if (*residue>1) *residue=1; /* previous residue now to right, so reduce */ 6919 6920 if (discard>len) { /* everything, +1, is being discarded */ 6921 /* guard digit is 0 */ 6922 /* residue is all the number [NB could be all 0s] */ 6923 if (*residue<=0) { /* not already positive */ 6924 count=len; /* avoids D2U */ 6925 for (up=lsu; count>0; up++, count-=DECDPUN) if (*up!=0) { /* found non-0 */ 6926 *residue=1; 6927 break; /* no need to check any others */ 6928 } 6929 } 6930 if (*residue!=0) *status|=DEC_Inexact; /* record inexactitude */ 6931 *dn->lsu=0; /* coefficient will now be 0 */ 6932 dn->digits=1; /* .. */ 6933 return; 6934 } /* total discard */ 6935 6936 /* partial discard [most common case] */ 6937 /* here, at least the first (most significant) discarded digit exists */ 6938 6939 /* spin up the number, noting residue during the spin, until get to */ 6940 /* the Unit with the first discarded digit. When reach it, extract */ 6941 /* it and remember its position */ 6942 count=0; 6943 for (up=lsu;; up++) { 6944 count+=DECDPUN; 6945 if (count>=discard) break; /* full ones all checked */ 6946 if (*up!=0) *residue=1; 6947 } /* up */ 6948 6949 /* here up -> Unit with first discarded digit */ 6950 cut=discard-(count-DECDPUN)-1; 6951 if (cut==DECDPUN-1) { /* unit-boundary case (fast) */ 6952 Unit half=(Unit)powers[DECDPUN]>>1; 6953 /* set residue directly */ 6954 if (*up>=half) { 6955 if (*up>half) *residue=7; 6956 else *residue+=5; /* add sticky bit */ 6957 } 6958 else { /* <half */ 6959 if (*up!=0) *residue=3; /* [else is 0, leave as sticky bit] */ 6960 } 6961 if (set->digits<=0) { /* special for Quantize/Subnormal :-( */ 6962 *dn->lsu=0; /* .. result is 0 */ 6963 dn->digits=1; /* .. */ 6964 } 6965 else { /* shift to least */ 6966 count=set->digits; /* now digits to end up with */ 6967 dn->digits=count; /* set the new length */ 6968 up++; /* move to next */ 6969 /* on unit boundary, so shift-down copy loop is simple */ 6970 for (target=dn->lsu; count>0; target++, up++, count-=DECDPUN) 6971 *target=*up; 6972 } 6973 } /* unit-boundary case */ 6974 6975 else { /* discard digit is in low digit(s), and not top digit */ 6976 uInt discard1; /* first discarded digit */ 6977 uInt quot, rem; /* for divisions */ 6978 if (cut==0) quot=*up; /* is at bottom of unit */ 6979 else /* cut>0 */ { /* it's not at bottom of unit */ 6980 #if DECDPUN<=4 6981 quot=QUOT10(*up, cut); 6982 rem=*up-quot*powers[cut]; 6983 #else 6984 rem=*up%powers[cut]; 6985 quot=*up/powers[cut]; 6986 #endif 6987 if (rem!=0) *residue=1; 6988 } 6989 /* discard digit is now at bottom of quot */ 6990 #if DECDPUN<=4 6991 temp=(quot*6554)>>16; /* fast /10 */ 6992 /* Vowels algorithm here not a win (9 instructions) */ 6993 discard1=quot-X10(temp); 6994 quot=temp; 6995 #else 6996 discard1=quot%10; 6997 quot=quot/10; 6998 #endif 6999 /* here, discard1 is the guard digit, and residue is everything */ 7000 /* else [use mapping array to accumulate residue safely] */ 7001 *residue+=resmap[discard1]; 7002 cut++; /* update cut */ 7003 /* here: up -> Unit of the array with bottom digit */ 7004 /* cut is the division point for each Unit */ 7005 /* quot holds the uncut high-order digits for the current unit */ 7006 if (set->digits<=0) { /* special for Quantize/Subnormal :-( */ 7007 *dn->lsu=0; /* .. result is 0 */ 7008 dn->digits=1; /* .. */ 7009 } 7010 else { /* shift to least needed */ 7011 count=set->digits; /* now digits to end up with */ 7012 dn->digits=count; /* set the new length */ 7013 /* shift-copy the coefficient array to the result number */ 7014 for (target=dn->lsu; ; target++) { 7015 *target=(Unit)quot; 7016 count-=(DECDPUN-cut); 7017 if (count<=0) break; 7018 up++; 7019 quot=*up; 7020 #if DECDPUN<=4 7021 quot=QUOT10(quot, cut); 7022 rem=*up-quot*powers[cut]; 7023 #else 7024 rem=quot%powers[cut]; 7025 quot=quot/powers[cut]; 7026 #endif 7027 *target=(Unit)(*target+rem*powers[DECDPUN-cut]); 7028 count-=cut; 7029 if (count<=0) break; 7030 } /* shift-copy loop */ 7031 } /* shift to least */ 7032 } /* not unit boundary */ 7033 7034 if (*residue!=0) *status|=DEC_Inexact; /* record inexactitude */ 7035 return; 7036 } /* decSetCoeff */ 7037 7038 /* ------------------------------------------------------------------ */ 7039 /* decApplyRound -- apply pending rounding to a number */ 7040 /* */ 7041 /* dn is the number, with space for set->digits digits */ 7042 /* set is the context [for size and rounding mode] */ 7043 /* residue indicates pending rounding, being any accumulated */ 7044 /* guard and sticky information. It may be: */ 7045 /* 6-9: rounding digit is >5 */ 7046 /* 5: rounding digit is exactly half-way */ 7047 /* 1-4: rounding digit is <5 and >0 */ 7048 /* 0: the coefficient is exact */ 7049 /* -1: as 1, but the hidden digits are subtractive, that */ 7050 /* is, of the opposite sign to dn. In this case the */ 7051 /* coefficient must be non-0. This case occurs when */ 7052 /* subtracting a small number (which can be reduced to */ 7053 /* a sticky bit); see decAddOp. */ 7054 /* status is the status accumulator, as usual */ 7055 /* */ 7056 /* This routine applies rounding while keeping the length of the */ 7057 /* coefficient constant. The exponent and status are unchanged */ 7058 /* except if: */ 7059 /* */ 7060 /* -- the coefficient was increased and is all nines (in which */ 7061 /* case Overflow could occur, and is handled directly here so */ 7062 /* the caller does not need to re-test for overflow) */ 7063 /* */ 7064 /* -- the coefficient was decreased and becomes all nines (in which */ 7065 /* case Underflow could occur, and is also handled directly). */ 7066 /* */ 7067 /* All fields in dn are updated as required. */ 7068 /* */ 7069 /* ------------------------------------------------------------------ */ 7070 static void decApplyRound(decNumber *dn, decContext *set, Int residue, 7071 uInt *status) { 7072 Int bump; /* 1 if coefficient needs to be incremented */ 7073 /* -1 if coefficient needs to be decremented */ 7074 7075 if (residue==0) return; /* nothing to apply */ 7076 7077 bump=0; /* assume a smooth ride */ 7078 7079 /* now decide whether, and how, to round, depending on mode */ 7080 switch (set->round) { 7081 case DEC_ROUND_05UP: { /* round zero or five up (for reround) */ 7082 /* This is the same as DEC_ROUND_DOWN unless there is a */ 7083 /* positive residue and the lsd of dn is 0 or 5, in which case */ 7084 /* it is bumped; when residue is <0, the number is therefore */ 7085 /* bumped down unless the final digit was 1 or 6 (in which */ 7086 /* case it is bumped down and then up -- a no-op) */ 7087 Int lsd5=*dn->lsu%5; /* get lsd and quintate */ 7088 if (residue<0 && lsd5!=1) bump=-1; 7089 else if (residue>0 && lsd5==0) bump=1; 7090 /* [bump==1 could be applied directly; use common path for clarity] */ 7091 break;} /* r-05 */ 7092 7093 case DEC_ROUND_DOWN: { 7094 /* no change, except if negative residue */ 7095 if (residue<0) bump=-1; 7096 break;} /* r-d */ 7097 7098 case DEC_ROUND_HALF_DOWN: { 7099 if (residue>5) bump=1; 7100 break;} /* r-h-d */ 7101 7102 case DEC_ROUND_HALF_EVEN: { 7103 if (residue>5) bump=1; /* >0.5 goes up */ 7104 else if (residue==5) { /* exactly 0.5000... */ 7105 /* 0.5 goes up iff [new] lsd is odd */ 7106 if (*dn->lsu & 0x01) bump=1; 7107 } 7108 break;} /* r-h-e */ 7109 7110 case DEC_ROUND_HALF_UP: { 7111 if (residue>=5) bump=1; 7112 break;} /* r-h-u */ 7113 7114 case DEC_ROUND_UP: { 7115 if (residue>0) bump=1; 7116 break;} /* r-u */ 7117 7118 case DEC_ROUND_CEILING: { 7119 /* same as _UP for positive numbers, and as _DOWN for negatives */ 7120 /* [negative residue cannot occur on 0] */ 7121 if (decNumberIsNegative(dn)) { 7122 if (residue<0) bump=-1; 7123 } 7124 else { 7125 if (residue>0) bump=1; 7126 } 7127 break;} /* r-c */ 7128 7129 case DEC_ROUND_FLOOR: { 7130 /* same as _UP for negative numbers, and as _DOWN for positive */ 7131 /* [negative residue cannot occur on 0] */ 7132 if (!decNumberIsNegative(dn)) { 7133 if (residue<0) bump=-1; 7134 } 7135 else { 7136 if (residue>0) bump=1; 7137 } 7138 break;} /* r-f */ 7139 7140 default: { /* e.g., DEC_ROUND_MAX */ 7141 *status|=DEC_Invalid_context; 7142 #if DECTRACE || (DECCHECK && DECVERB) 7143 printf("Unknown rounding mode: %d\n", set->round); 7144 #endif 7145 break;} 7146 } /* switch */ 7147 7148 /* now bump the number, up or down, if need be */ 7149 if (bump==0) return; /* no action required */ 7150 7151 /* Simply use decUnitAddSub unless bumping up and the number is */ 7152 /* all nines. In this special case set to 100... explicitly */ 7153 /* and adjust the exponent by one (as otherwise could overflow */ 7154 /* the array) */ 7155 /* Similarly handle all-nines result if bumping down. */ 7156 if (bump>0) { 7157 Unit *up; /* work */ 7158 uInt count=dn->digits; /* digits to be checked */ 7159 for (up=dn->lsu; ; up++) { 7160 if (count<=DECDPUN) { 7161 /* this is the last Unit (the msu) */ 7162 if (*up!=powers[count]-1) break; /* not still 9s */ 7163 /* here if it, too, is all nines */ 7164 *up=(Unit)powers[count-1]; /* here 999 -> 100 etc. */ 7165 for (up=up-1; up>=dn->lsu; up--) *up=0; /* others all to 0 */ 7166 dn->exponent++; /* and bump exponent */ 7167 /* [which, very rarely, could cause Overflow...] */ 7168 if ((dn->exponent+dn->digits)>set->emax+1) { 7169 decSetOverflow(dn, set, status); 7170 } 7171 return; /* done */ 7172 } 7173 /* a full unit to check, with more to come */ 7174 if (*up!=DECDPUNMAX) break; /* not still 9s */ 7175 count-=DECDPUN; 7176 } /* up */ 7177 } /* bump>0 */ 7178 else { /* -1 */ 7179 /* here checking for a pre-bump of 1000... (leading 1, all */ 7180 /* other digits zero) */ 7181 Unit *up, *sup; /* work */ 7182 uInt count=dn->digits; /* digits to be checked */ 7183 for (up=dn->lsu; ; up++) { 7184 if (count<=DECDPUN) { 7185 /* this is the last Unit (the msu) */ 7186 if (*up!=powers[count-1]) break; /* not 100.. */ 7187 /* here if have the 1000... case */ 7188 sup=up; /* save msu pointer */ 7189 *up=(Unit)powers[count]-1; /* here 100 in msu -> 999 */ 7190 /* others all to all-nines, too */ 7191 for (up=up-1; up>=dn->lsu; up--) *up=(Unit)powers[DECDPUN]-1; 7192 dn->exponent--; /* and bump exponent */ 7193 7194 /* iff the number was at the subnormal boundary (exponent=etiny) */ 7195 /* then the exponent is now out of range, so it will in fact get */ 7196 /* clamped to etiny and the final 9 dropped. */ 7197 /* printf(">> emin=%d exp=%d sdig=%d\n", set->emin, */ 7198 /* dn->exponent, set->digits); */ 7199 if (dn->exponent+1==set->emin-set->digits+1) { 7200 if (count==1 && dn->digits==1) *sup=0; /* here 9 -> 0[.9] */ 7201 else { 7202 *sup=(Unit)powers[count-1]-1; /* here 999.. in msu -> 99.. */ 7203 dn->digits--; 7204 } 7205 dn->exponent++; 7206 *status|=DEC_Underflow | DEC_Subnormal | DEC_Inexact | DEC_Rounded; 7207 } 7208 return; /* done */ 7209 } 7210 7211 /* a full unit to check, with more to come */ 7212 if (*up!=0) break; /* not still 0s */ 7213 count-=DECDPUN; 7214 } /* up */ 7215 7216 } /* bump<0 */ 7217 7218 /* Actual bump needed. Do it. */ 7219 decUnitAddSub(dn->lsu, D2U(dn->digits), uarrone, 1, 0, dn->lsu, bump); 7220 } /* decApplyRound */ 7221 7222 #if DECSUBSET 7223 /* ------------------------------------------------------------------ */ 7224 /* decFinish -- finish processing a number */ 7225 /* */ 7226 /* dn is the number */ 7227 /* set is the context */ 7228 /* residue is the rounding accumulator (as in decApplyRound) */ 7229 /* status is the accumulator */ 7230 /* */ 7231 /* This finishes off the current number by: */ 7232 /* 1. If not extended: */ 7233 /* a. Converting a zero result to clean '0' */ 7234 /* b. Reducing positive exponents to 0, if would fit in digits */ 7235 /* 2. Checking for overflow and subnormals (always) */ 7236 /* Note this is just Finalize when no subset arithmetic. */ 7237 /* All fields are updated as required. */ 7238 /* ------------------------------------------------------------------ */ 7239 static void decFinish(decNumber *dn, decContext *set, Int *residue, 7240 uInt *status) { 7241 if (!set->extended) { 7242 if ISZERO(dn) { /* value is zero */ 7243 dn->exponent=0; /* clean exponent .. */ 7244 dn->bits=0; /* .. and sign */ 7245 return; /* no error possible */ 7246 } 7247 if (dn->exponent>=0) { /* non-negative exponent */ 7248 /* >0; reduce to integer if possible */ 7249 if (set->digits >= (dn->exponent+dn->digits)) { 7250 dn->digits=decShiftToMost(dn->lsu, dn->digits, dn->exponent); 7251 dn->exponent=0; 7252 } 7253 } 7254 } /* !extended */ 7255 7256 decFinalize(dn, set, residue, status); 7257 } /* decFinish */ 7258 #endif 7259 7260 /* ------------------------------------------------------------------ */ 7261 /* decFinalize -- final check, clamp, and round of a number */ 7262 /* */ 7263 /* dn is the number */ 7264 /* set is the context */ 7265 /* residue is the rounding accumulator (as in decApplyRound) */ 7266 /* status is the status accumulator */ 7267 /* */ 7268 /* This finishes off the current number by checking for subnormal */ 7269 /* results, applying any pending rounding, checking for overflow, */ 7270 /* and applying any clamping. */ 7271 /* Underflow and overflow conditions are raised as appropriate. */ 7272 /* All fields are updated as required. */ 7273 /* ------------------------------------------------------------------ */ 7274 static void decFinalize(decNumber *dn, decContext *set, Int *residue, 7275 uInt *status) { 7276 Int shift; /* shift needed if clamping */ 7277 Int tinyexp=set->emin-dn->digits+1; /* precalculate subnormal boundary */ 7278 7279 /* Must be careful, here, when checking the exponent as the */ 7280 /* adjusted exponent could overflow 31 bits [because it may already */ 7281 /* be up to twice the expected]. */ 7282 7283 /* First test for subnormal. This must be done before any final */ 7284 /* round as the result could be rounded to Nmin or 0. */ 7285 if (dn->exponent<=tinyexp) { /* prefilter */ 7286 Int comp; 7287 decNumber nmin; 7288 /* A very nasty case here is dn == Nmin and residue<0 */ 7289 if (dn->exponent<tinyexp) { 7290 /* Go handle subnormals; this will apply round if needed. */ 7291 decSetSubnormal(dn, set, residue, status); 7292 return; 7293 } 7294 /* Equals case: only subnormal if dn=Nmin and negative residue */ 7295 uprv_decNumberZero(&nmin); 7296 nmin.lsu[0]=1; 7297 nmin.exponent=set->emin; 7298 comp=decCompare(dn, &nmin, 1); /* (signless compare) */ 7299 if (comp==BADINT) { /* oops */ 7300 *status|=DEC_Insufficient_storage; /* abandon... */ 7301 return; 7302 } 7303 if (*residue<0 && comp==0) { /* neg residue and dn==Nmin */ 7304 decApplyRound(dn, set, *residue, status); /* might force down */ 7305 decSetSubnormal(dn, set, residue, status); 7306 return; 7307 } 7308 } 7309 7310 /* now apply any pending round (this could raise overflow). */ 7311 if (*residue!=0) decApplyRound(dn, set, *residue, status); 7312 7313 /* Check for overflow [redundant in the 'rare' case] or clamp */ 7314 if (dn->exponent<=set->emax-set->digits+1) return; /* neither needed */ 7315 7316 7317 /* here when might have an overflow or clamp to do */ 7318 if (dn->exponent>set->emax-dn->digits+1) { /* too big */ 7319 decSetOverflow(dn, set, status); 7320 return; 7321 } 7322 /* here when the result is normal but in clamp range */ 7323 if (!set->clamp) return; 7324 7325 /* here when need to apply the IEEE exponent clamp (fold-down) */ 7326 shift=dn->exponent-(set->emax-set->digits+1); 7327 7328 /* shift coefficient (if non-zero) */ 7329 if (!ISZERO(dn)) { 7330 dn->digits=decShiftToMost(dn->lsu, dn->digits, shift); 7331 } 7332 dn->exponent-=shift; /* adjust the exponent to match */ 7333 *status|=DEC_Clamped; /* and record the dirty deed */ 7334 return; 7335 } /* decFinalize */ 7336 7337 /* ------------------------------------------------------------------ */ 7338 /* decSetOverflow -- set number to proper overflow value */ 7339 /* */ 7340 /* dn is the number (used for sign [only] and result) */ 7341 /* set is the context [used for the rounding mode, etc.] */ 7342 /* status contains the current status to be updated */ 7343 /* */ 7344 /* This sets the sign of a number and sets its value to either */ 7345 /* Infinity or the maximum finite value, depending on the sign of */ 7346 /* dn and the rounding mode, following IEEE 754 rules. */ 7347 /* ------------------------------------------------------------------ */ 7348 static void decSetOverflow(decNumber *dn, decContext *set, uInt *status) { 7349 Flag needmax=0; /* result is maximum finite value */ 7350 uByte sign=dn->bits&DECNEG; /* clean and save sign bit */ 7351 7352 if (ISZERO(dn)) { /* zero does not overflow magnitude */ 7353 Int emax=set->emax; /* limit value */ 7354 if (set->clamp) emax-=set->digits-1; /* lower if clamping */ 7355 if (dn->exponent>emax) { /* clamp required */ 7356 dn->exponent=emax; 7357 *status|=DEC_Clamped; 7358 } 7359 return; 7360 } 7361 7362 uprv_decNumberZero(dn); 7363 switch (set->round) { 7364 case DEC_ROUND_DOWN: { 7365 needmax=1; /* never Infinity */ 7366 break;} /* r-d */ 7367 case DEC_ROUND_05UP: { 7368 needmax=1; /* never Infinity */ 7369 break;} /* r-05 */ 7370 case DEC_ROUND_CEILING: { 7371 if (sign) needmax=1; /* Infinity if non-negative */ 7372 break;} /* r-c */ 7373 case DEC_ROUND_FLOOR: { 7374 if (!sign) needmax=1; /* Infinity if negative */ 7375 break;} /* r-f */ 7376 default: break; /* Infinity in all other cases */ 7377 } 7378 if (needmax) { 7379 decSetMaxValue(dn, set); 7380 dn->bits=sign; /* set sign */ 7381 } 7382 else dn->bits=sign|DECINF; /* Value is +/-Infinity */ 7383 *status|=DEC_Overflow | DEC_Inexact | DEC_Rounded; 7384 } /* decSetOverflow */ 7385 7386 /* ------------------------------------------------------------------ */ 7387 /* decSetMaxValue -- set number to +Nmax (maximum normal value) */ 7388 /* */ 7389 /* dn is the number to set */ 7390 /* set is the context [used for digits and emax] */ 7391 /* */ 7392 /* This sets the number to the maximum positive value. */ 7393 /* ------------------------------------------------------------------ */ 7394 static void decSetMaxValue(decNumber *dn, decContext *set) { 7395 Unit *up; /* work */ 7396 Int count=set->digits; /* nines to add */ 7397 dn->digits=count; 7398 /* fill in all nines to set maximum value */ 7399 for (up=dn->lsu; ; up++) { 7400 if (count>DECDPUN) *up=DECDPUNMAX; /* unit full o'nines */ 7401 else { /* this is the msu */ 7402 *up=(Unit)(powers[count]-1); 7403 break; 7404 } 7405 count-=DECDPUN; /* filled those digits */ 7406 } /* up */ 7407 dn->bits=0; /* + sign */ 7408 dn->exponent=set->emax-set->digits+1; 7409 } /* decSetMaxValue */ 7410 7411 /* ------------------------------------------------------------------ */ 7412 /* decSetSubnormal -- process value whose exponent is <Emin */ 7413 /* */ 7414 /* dn is the number (used as input as well as output; it may have */ 7415 /* an allowed subnormal value, which may need to be rounded) */ 7416 /* set is the context [used for the rounding mode] */ 7417 /* residue is any pending residue */ 7418 /* status contains the current status to be updated */ 7419 /* */ 7420 /* If subset mode, set result to zero and set Underflow flags. */ 7421 /* */ 7422 /* Value may be zero with a low exponent; this does not set Subnormal */ 7423 /* but the exponent will be clamped to Etiny. */ 7424 /* */ 7425 /* Otherwise ensure exponent is not out of range, and round as */ 7426 /* necessary. Underflow is set if the result is Inexact. */ 7427 /* ------------------------------------------------------------------ */ 7428 static void decSetSubnormal(decNumber *dn, decContext *set, Int *residue, 7429 uInt *status) { 7430 decContext workset; /* work */ 7431 Int etiny, adjust; /* .. */ 7432 7433 #if DECSUBSET 7434 /* simple set to zero and 'hard underflow' for subset */ 7435 if (!set->extended) { 7436 uprv_decNumberZero(dn); 7437 /* always full overflow */ 7438 *status|=DEC_Underflow | DEC_Subnormal | DEC_Inexact | DEC_Rounded; 7439 return; 7440 } 7441 #endif 7442 7443 /* Full arithmetic -- allow subnormals, rounded to minimum exponent */ 7444 /* (Etiny) if needed */ 7445 etiny=set->emin-(set->digits-1); /* smallest allowed exponent */ 7446 7447 if ISZERO(dn) { /* value is zero */ 7448 /* residue can never be non-zero here */ 7449 #if DECCHECK 7450 if (*residue!=0) { 7451 printf("++ Subnormal 0 residue %ld\n", (LI)*residue); 7452 *status|=DEC_Invalid_operation; 7453 } 7454 #endif 7455 if (dn->exponent<etiny) { /* clamp required */ 7456 dn->exponent=etiny; 7457 *status|=DEC_Clamped; 7458 } 7459 return; 7460 } 7461 7462 *status|=DEC_Subnormal; /* have a non-zero subnormal */ 7463 adjust=etiny-dn->exponent; /* calculate digits to remove */ 7464 if (adjust<=0) { /* not out of range; unrounded */ 7465 /* residue can never be non-zero here, except in the Nmin-residue */ 7466 /* case (which is a subnormal result), so can take fast-path here */ 7467 /* it may already be inexact (from setting the coefficient) */ 7468 if (*status&DEC_Inexact) *status|=DEC_Underflow; 7469 return; 7470 } 7471 7472 /* adjust>0, so need to rescale the result so exponent becomes Etiny */ 7473 /* [this code is similar to that in rescale] */ 7474 workset=*set; /* clone rounding, etc. */ 7475 workset.digits=dn->digits-adjust; /* set requested length */ 7476 workset.emin-=adjust; /* and adjust emin to match */ 7477 /* [note that the latter can be <1, here, similar to Rescale case] */ 7478 decSetCoeff(dn, &workset, dn->lsu, dn->digits, residue, status); 7479 decApplyRound(dn, &workset, *residue, status); 7480 7481 /* Use 754 default rule: Underflow is set iff Inexact */ 7482 /* [independent of whether trapped] */ 7483 if (*status&DEC_Inexact) *status|=DEC_Underflow; 7484 7485 /* if rounded up a 999s case, exponent will be off by one; adjust */ 7486 /* back if so [it will fit, because it was shortened earlier] */ 7487 if (dn->exponent>etiny) { 7488 dn->digits=decShiftToMost(dn->lsu, dn->digits, 1); 7489 dn->exponent--; /* (re)adjust the exponent. */ 7490 } 7491 7492 /* if rounded to zero, it is by definition clamped... */ 7493 if (ISZERO(dn)) *status|=DEC_Clamped; 7494 } /* decSetSubnormal */ 7495 7496 /* ------------------------------------------------------------------ */ 7497 /* decCheckMath - check entry conditions for a math function */ 7498 /* */ 7499 /* This checks the context and the operand */ 7500 /* */ 7501 /* rhs is the operand to check */ 7502 /* set is the context to check */ 7503 /* status is unchanged if both are good */ 7504 /* */ 7505 /* returns non-zero if status is changed, 0 otherwise */ 7506 /* */ 7507 /* Restrictions enforced: */ 7508 /* */ 7509 /* digits, emax, and -emin in the context must be less than */ 7510 /* DEC_MAX_MATH (999999), and A must be within these bounds if */ 7511 /* non-zero. Invalid_operation is set in the status if a */ 7512 /* restriction is violated. */ 7513 /* ------------------------------------------------------------------ */ 7514 static uInt decCheckMath(const decNumber *rhs, decContext *set, 7515 uInt *status) { 7516 uInt save=*status; /* record */ 7517 if (set->digits>DEC_MAX_MATH 7518 || set->emax>DEC_MAX_MATH 7519 || -set->emin>DEC_MAX_MATH) *status|=DEC_Invalid_context; 7520 else if ((rhs->digits>DEC_MAX_MATH 7521 || rhs->exponent+rhs->digits>DEC_MAX_MATH+1 7522 || rhs->exponent+rhs->digits<2*(1-DEC_MAX_MATH)) 7523 && !ISZERO(rhs)) *status|=DEC_Invalid_operation; 7524 return (*status!=save); 7525 } /* decCheckMath */ 7526 7527 /* ------------------------------------------------------------------ */ 7528 /* decGetInt -- get integer from a number */ 7529 /* */ 7530 /* dn is the number [which will not be altered] */ 7531 /* */ 7532 /* returns one of: */ 7533 /* BADINT if there is a non-zero fraction */ 7534 /* the converted integer */ 7535 /* BIGEVEN if the integer is even and magnitude > 2*10**9 */ 7536 /* BIGODD if the integer is odd and magnitude > 2*10**9 */ 7537 /* */ 7538 /* This checks and gets a whole number from the input decNumber. */ 7539 /* The sign can be determined from dn by the caller when BIGEVEN or */ 7540 /* BIGODD is returned. */ 7541 /* ------------------------------------------------------------------ */ 7542 static Int decGetInt(const decNumber *dn) { 7543 Int theInt; /* result accumulator */ 7544 const Unit *up; /* work */ 7545 Int got; /* digits (real or not) processed */ 7546 Int ilength=dn->digits+dn->exponent; /* integral length */ 7547 Flag neg=decNumberIsNegative(dn); /* 1 if -ve */ 7548 7549 /* The number must be an integer that fits in 10 digits */ 7550 /* Assert, here, that 10 is enough for any rescale Etiny */ 7551 #if DEC_MAX_EMAX > 999999999 7552 #error GetInt may need updating [for Emax] 7553 #endif 7554 #if DEC_MIN_EMIN < -999999999 7555 #error GetInt may need updating [for Emin] 7556 #endif 7557 if (ISZERO(dn)) return 0; /* zeros are OK, with any exponent */ 7558 7559 up=dn->lsu; /* ready for lsu */ 7560 theInt=0; /* ready to accumulate */ 7561 if (dn->exponent>=0) { /* relatively easy */ 7562 /* no fractional part [usual]; allow for positive exponent */ 7563 got=dn->exponent; 7564 } 7565 else { /* -ve exponent; some fractional part to check and discard */ 7566 Int count=-dn->exponent; /* digits to discard */ 7567 /* spin up whole units until reach the Unit with the unit digit */ 7568 for (; count>=DECDPUN; up++) { 7569 if (*up!=0) return BADINT; /* non-zero Unit to discard */ 7570 count-=DECDPUN; 7571 } 7572 if (count==0) got=0; /* [a multiple of DECDPUN] */ 7573 else { /* [not multiple of DECDPUN] */ 7574 Int rem; /* work */ 7575 /* slice off fraction digits and check for non-zero */ 7576 #if DECDPUN<=4 7577 theInt=QUOT10(*up, count); 7578 rem=*up-theInt*powers[count]; 7579 #else 7580 rem=*up%powers[count]; /* slice off discards */ 7581 theInt=*up/powers[count]; 7582 #endif 7583 if (rem!=0) return BADINT; /* non-zero fraction */ 7584 /* it looks good */ 7585 got=DECDPUN-count; /* number of digits so far */ 7586 up++; /* ready for next */ 7587 } 7588 } 7589 /* now it's known there's no fractional part */ 7590 7591 /* tricky code now, to accumulate up to 9.3 digits */ 7592 if (got==0) {theInt=*up; got+=DECDPUN; up++;} /* ensure lsu is there */ 7593 7594 if (ilength<11) { 7595 Int save=theInt; 7596 /* collect any remaining unit(s) */ 7597 for (; got<ilength; up++) { 7598 theInt+=*up*powers[got]; 7599 got+=DECDPUN; 7600 } 7601 if (ilength==10) { /* need to check for wrap */ 7602 if (theInt/(Int)powers[got-DECDPUN]!=(Int)*(up-1)) ilength=11; 7603 /* [that test also disallows the BADINT result case] */ 7604 else if (neg && theInt>1999999997) ilength=11; 7605 else if (!neg && theInt>999999999) ilength=11; 7606 if (ilength==11) theInt=save; /* restore correct low bit */ 7607 } 7608 } 7609 7610 if (ilength>10) { /* too big */ 7611 if (theInt&1) return BIGODD; /* bottom bit 1 */ 7612 return BIGEVEN; /* bottom bit 0 */ 7613 } 7614 7615 if (neg) theInt=-theInt; /* apply sign */ 7616 return theInt; 7617 } /* decGetInt */ 7618 7619 /* ------------------------------------------------------------------ */ 7620 /* decDecap -- decapitate the coefficient of a number */ 7621 /* */ 7622 /* dn is the number to be decapitated */ 7623 /* drop is the number of digits to be removed from the left of dn; */ 7624 /* this must be <= dn->digits (if equal, the coefficient is */ 7625 /* set to 0) */ 7626 /* */ 7627 /* Returns dn; dn->digits will be <= the initial digits less drop */ 7628 /* (after removing drop digits there may be leading zero digits */ 7629 /* which will also be removed). Only dn->lsu and dn->digits change. */ 7630 /* ------------------------------------------------------------------ */ 7631 static decNumber *decDecap(decNumber *dn, Int drop) { 7632 Unit *msu; /* -> target cut point */ 7633 Int cut; /* work */ 7634 if (drop>=dn->digits) { /* losing the whole thing */ 7635 #if DECCHECK 7636 if (drop>dn->digits) 7637 printf("decDecap called with drop>digits [%ld>%ld]\n", 7638 (LI)drop, (LI)dn->digits); 7639 #endif 7640 dn->lsu[0]=0; 7641 dn->digits=1; 7642 return dn; 7643 } 7644 msu=dn->lsu+D2U(dn->digits-drop)-1; /* -> likely msu */ 7645 cut=MSUDIGITS(dn->digits-drop); /* digits to be in use in msu */ 7646 if (cut!=DECDPUN) *msu%=powers[cut]; /* clear left digits */ 7647 /* that may have left leading zero digits, so do a proper count... */ 7648 dn->digits=decGetDigits(dn->lsu, msu-dn->lsu+1); 7649 return dn; 7650 } /* decDecap */ 7651 7652 /* ------------------------------------------------------------------ */ 7653 /* decBiStr -- compare string with pairwise options */ 7654 /* */ 7655 /* targ is the string to compare */ 7656 /* str1 is one of the strings to compare against (length may be 0) */ 7657 /* str2 is the other; it must be the same length as str1 */ 7658 /* */ 7659 /* returns 1 if strings compare equal, (that is, it is the same */ 7660 /* length as str1 and str2, and each character of targ is in either */ 7661 /* str1 or str2 in the corresponding position), or 0 otherwise */ 7662 /* */ 7663 /* This is used for generic caseless compare, including the awkward */ 7664 /* case of the Turkish dotted and dotless Is. Use as (for example): */ 7665 /* if (decBiStr(test, "mike", "MIKE")) ... */ 7666 /* ------------------------------------------------------------------ */ 7667 static Flag decBiStr(const char *targ, const char *str1, const char *str2) { 7668 for (;;targ++, str1++, str2++) { 7669 if (*targ!=*str1 && *targ!=*str2) return 0; 7670 /* *targ has a match in one (or both, if terminator) */ 7671 if (*targ=='\0') break; 7672 } /* forever */ 7673 return 1; 7674 } /* decBiStr */ 7675 7676 /* ------------------------------------------------------------------ */ 7677 /* decNaNs -- handle NaN operand or operands */ 7678 /* */ 7679 /* res is the result number */ 7680 /* lhs is the first operand */ 7681 /* rhs is the second operand, or NULL if none */ 7682 /* context is used to limit payload length */ 7683 /* status contains the current status */ 7684 /* returns res in case convenient */ 7685 /* */ 7686 /* Called when one or both operands is a NaN, and propagates the */ 7687 /* appropriate result to res. When an sNaN is found, it is changed */ 7688 /* to a qNaN and Invalid operation is set. */ 7689 /* ------------------------------------------------------------------ */ 7690 static decNumber * decNaNs(decNumber *res, const decNumber *lhs, 7691 const decNumber *rhs, decContext *set, 7692 uInt *status) { 7693 /* This decision tree ends up with LHS being the source pointer, */ 7694 /* and status updated if need be */ 7695 if (lhs->bits & DECSNAN) 7696 *status|=DEC_Invalid_operation | DEC_sNaN; 7697 else if (rhs==NULL); 7698 else if (rhs->bits & DECSNAN) { 7699 lhs=rhs; 7700 *status|=DEC_Invalid_operation | DEC_sNaN; 7701 } 7702 else if (lhs->bits & DECNAN); 7703 else lhs=rhs; 7704 7705 /* propagate the payload */ 7706 if (lhs->digits<=set->digits) uprv_decNumberCopy(res, lhs); /* easy */ 7707 else { /* too long */ 7708 const Unit *ul; 7709 Unit *ur, *uresp1; 7710 /* copy safe number of units, then decapitate */ 7711 res->bits=lhs->bits; /* need sign etc. */ 7712 uresp1=res->lsu+D2U(set->digits); 7713 for (ur=res->lsu, ul=lhs->lsu; ur<uresp1; ur++, ul++) *ur=*ul; 7714 res->digits=D2U(set->digits)*DECDPUN; 7715 /* maybe still too long */ 7716 if (res->digits>set->digits) decDecap(res, res->digits-set->digits); 7717 } 7718 7719 res->bits&=~DECSNAN; /* convert any sNaN to NaN, while */ 7720 res->bits|=DECNAN; /* .. preserving sign */ 7721 res->exponent=0; /* clean exponent */ 7722 /* [coefficient was copied/decapitated] */ 7723 return res; 7724 } /* decNaNs */ 7725 7726 /* ------------------------------------------------------------------ */ 7727 /* decStatus -- apply non-zero status */ 7728 /* */ 7729 /* dn is the number to set if error */ 7730 /* status contains the current status (not yet in context) */ 7731 /* set is the context */ 7732 /* */ 7733 /* If the status is an error status, the number is set to a NaN, */ 7734 /* unless the error was an overflow, divide-by-zero, or underflow, */ 7735 /* in which case the number will have already been set. */ 7736 /* */ 7737 /* The context status is then updated with the new status. Note that */ 7738 /* this may raise a signal, so control may never return from this */ 7739 /* routine (hence resources must be recovered before it is called). */ 7740 /* ------------------------------------------------------------------ */ 7741 static void decStatus(decNumber *dn, uInt status, decContext *set) { 7742 if (status & DEC_NaNs) { /* error status -> NaN */ 7743 /* if cause was an sNaN, clear and propagate [NaN is already set up] */ 7744 if (status & DEC_sNaN) status&=~DEC_sNaN; 7745 else { 7746 uprv_decNumberZero(dn); /* other error: clean throughout */ 7747 dn->bits=DECNAN; /* and make a quiet NaN */ 7748 } 7749 } 7750 uprv_decContextSetStatus(set, status); /* [may not return] */ 7751 return; 7752 } /* decStatus */ 7753 7754 /* ------------------------------------------------------------------ */ 7755 /* decGetDigits -- count digits in a Units array */ 7756 /* */ 7757 /* uar is the Unit array holding the number (this is often an */ 7758 /* accumulator of some sort) */ 7759 /* len is the length of the array in units [>=1] */ 7760 /* */ 7761 /* returns the number of (significant) digits in the array */ 7762 /* */ 7763 /* All leading zeros are excluded, except the last if the array has */ 7764 /* only zero Units. */ 7765 /* ------------------------------------------------------------------ */ 7766 /* This may be called twice during some operations. */ 7767 static Int decGetDigits(Unit *uar, Int len) { 7768 Unit *up=uar+(len-1); /* -> msu */ 7769 Int digits=(len-1)*DECDPUN+1; /* possible digits excluding msu */ 7770 #if DECDPUN>4 7771 uInt const *pow; /* work */ 7772 #endif 7773 /* (at least 1 in final msu) */ 7774 #if DECCHECK 7775 if (len<1) printf("decGetDigits called with len<1 [%ld]\n", (LI)len); 7776 #endif 7777 7778 for (; up>=uar; up--) { 7779 if (*up==0) { /* unit is all 0s */ 7780 if (digits==1) break; /* a zero has one digit */ 7781 digits-=DECDPUN; /* adjust for 0 unit */ 7782 continue;} 7783 /* found the first (most significant) non-zero Unit */ 7784 #if DECDPUN>1 /* not done yet */ 7785 if (*up<10) break; /* is 1-9 */ 7786 digits++; 7787 #if DECDPUN>2 /* not done yet */ 7788 if (*up<100) break; /* is 10-99 */ 7789 digits++; 7790 #if DECDPUN>3 /* not done yet */ 7791 if (*up<1000) break; /* is 100-999 */ 7792 digits++; 7793 #if DECDPUN>4 /* count the rest ... */ 7794 for (pow=&powers[4]; *up>=*pow; pow++) digits++; 7795 #endif 7796 #endif 7797 #endif 7798 #endif 7799 break; 7800 } /* up */ 7801 return digits; 7802 } /* decGetDigits */ 7803 7804 #if DECTRACE | DECCHECK 7805 /* ------------------------------------------------------------------ */ 7806 /* decNumberShow -- display a number [debug aid] */ 7807 /* dn is the number to show */ 7808 /* */ 7809 /* Shows: sign, exponent, coefficient (msu first), digits */ 7810 /* or: sign, special-value */ 7811 /* ------------------------------------------------------------------ */ 7812 /* this is public so other modules can use it */ 7813 void uprv_decNumberShow(const decNumber *dn) { 7814 const Unit *up; /* work */ 7815 uInt u, d; /* .. */ 7816 Int cut; /* .. */ 7817 char isign='+'; /* main sign */ 7818 if (dn==NULL) { 7819 printf("NULL\n"); 7820 return;} 7821 if (decNumberIsNegative(dn)) isign='-'; 7822 printf(" >> %c ", isign); 7823 if (dn->bits&DECSPECIAL) { /* Is a special value */ 7824 if (decNumberIsInfinite(dn)) printf("Infinity"); 7825 else { /* a NaN */ 7826 if (dn->bits&DECSNAN) printf("sNaN"); /* signalling NaN */ 7827 else printf("NaN"); 7828 } 7829 /* if coefficient and exponent are 0, no more to do */ 7830 if (dn->exponent==0 && dn->digits==1 && *dn->lsu==0) { 7831 printf("\n"); 7832 return;} 7833 /* drop through to report other information */ 7834 printf(" "); 7835 } 7836 7837 /* now carefully display the coefficient */ 7838 up=dn->lsu+D2U(dn->digits)-1; /* msu */ 7839 printf("%ld", (LI)*up); 7840 for (up=up-1; up>=dn->lsu; up--) { 7841 u=*up; 7842 printf(":"); 7843 for (cut=DECDPUN-1; cut>=0; cut--) { 7844 d=u/powers[cut]; 7845 u-=d*powers[cut]; 7846 printf("%ld", (LI)d); 7847 } /* cut */ 7848 } /* up */ 7849 if (dn->exponent!=0) { 7850 char esign='+'; 7851 if (dn->exponent<0) esign='-'; 7852 printf(" E%c%ld", esign, (LI)abs(dn->exponent)); 7853 } 7854 printf(" [%ld]\n", (LI)dn->digits); 7855 } /* decNumberShow */ 7856 #endif 7857 7858 #if DECTRACE || DECCHECK 7859 /* ------------------------------------------------------------------ */ 7860 /* decDumpAr -- display a unit array [debug/check aid] */ 7861 /* name is a single-character tag name */ 7862 /* ar is the array to display */ 7863 /* len is the length of the array in Units */ 7864 /* ------------------------------------------------------------------ */ 7865 static void decDumpAr(char name, const Unit *ar, Int len) { 7866 Int i; 7867 const char *spec; 7868 #if DECDPUN==9 7869 spec="%09d "; 7870 #elif DECDPUN==8 7871 spec="%08d "; 7872 #elif DECDPUN==7 7873 spec="%07d "; 7874 #elif DECDPUN==6 7875 spec="%06d "; 7876 #elif DECDPUN==5 7877 spec="%05d "; 7878 #elif DECDPUN==4 7879 spec="%04d "; 7880 #elif DECDPUN==3 7881 spec="%03d "; 7882 #elif DECDPUN==2 7883 spec="%02d "; 7884 #else 7885 spec="%d "; 7886 #endif 7887 printf(" :%c: ", name); 7888 for (i=len-1; i>=0; i--) { 7889 if (i==len-1) printf("%ld ", (LI)ar[i]); 7890 else printf(spec, ar[i]); 7891 } 7892 printf("\n"); 7893 return;} 7894 #endif 7895 7896 #if DECCHECK 7897 /* ------------------------------------------------------------------ */ 7898 /* decCheckOperands -- check operand(s) to a routine */ 7899 /* res is the result structure (not checked; it will be set to */ 7900 /* quiet NaN if error found (and it is not NULL)) */ 7901 /* lhs is the first operand (may be DECUNRESU) */ 7902 /* rhs is the second (may be DECUNUSED) */ 7903 /* set is the context (may be DECUNCONT) */ 7904 /* returns 0 if both operands, and the context are clean, or 1 */ 7905 /* otherwise (in which case the context will show an error, */ 7906 /* unless NULL). Note that res is not cleaned; caller should */ 7907 /* handle this so res=NULL case is safe. */ 7908 /* The caller is expected to abandon immediately if 1 is returned. */ 7909 /* ------------------------------------------------------------------ */ 7910 static Flag decCheckOperands(decNumber *res, const decNumber *lhs, 7911 const decNumber *rhs, decContext *set) { 7912 Flag bad=0; 7913 if (set==NULL) { /* oops; hopeless */ 7914 #if DECTRACE || DECVERB 7915 printf("Reference to context is NULL.\n"); 7916 #endif 7917 bad=1; 7918 return 1;} 7919 else if (set!=DECUNCONT 7920 && (set->digits<1 || set->round>=DEC_ROUND_MAX)) { 7921 bad=1; 7922 #if DECTRACE || DECVERB 7923 printf("Bad context [digits=%ld round=%ld].\n", 7924 (LI)set->digits, (LI)set->round); 7925 #endif 7926 } 7927 else { 7928 if (res==NULL) { 7929 bad=1; 7930 #if DECTRACE 7931 /* this one not DECVERB as standard tests include NULL */ 7932 printf("Reference to result is NULL.\n"); 7933 #endif 7934 } 7935 if (!bad && lhs!=DECUNUSED) bad=(decCheckNumber(lhs)); 7936 if (!bad && rhs!=DECUNUSED) bad=(decCheckNumber(rhs)); 7937 } 7938 if (bad) { 7939 if (set!=DECUNCONT) uprv_decContextSetStatus(set, DEC_Invalid_operation); 7940 if (res!=DECUNRESU && res!=NULL) { 7941 uprv_decNumberZero(res); 7942 res->bits=DECNAN; /* qNaN */ 7943 } 7944 } 7945 return bad; 7946 } /* decCheckOperands */ 7947 7948 /* ------------------------------------------------------------------ */ 7949 /* decCheckNumber -- check a number */ 7950 /* dn is the number to check */ 7951 /* returns 0 if the number is clean, or 1 otherwise */ 7952 /* */ 7953 /* The number is considered valid if it could be a result from some */ 7954 /* operation in some valid context. */ 7955 /* ------------------------------------------------------------------ */ 7956 static Flag decCheckNumber(const decNumber *dn) { 7957 const Unit *up; /* work */ 7958 uInt maxuint; /* .. */ 7959 Int ae, d, digits; /* .. */ 7960 Int emin, emax; /* .. */ 7961 7962 if (dn==NULL) { /* hopeless */ 7963 #if DECTRACE 7964 /* this one not DECVERB as standard tests include NULL */ 7965 printf("Reference to decNumber is NULL.\n"); 7966 #endif 7967 return 1;} 7968 7969 /* check special values */ 7970 if (dn->bits & DECSPECIAL) { 7971 if (dn->exponent!=0) { 7972 #if DECTRACE || DECVERB 7973 printf("Exponent %ld (not 0) for a special value [%02x].\n", 7974 (LI)dn->exponent, dn->bits); 7975 #endif 7976 return 1;} 7977 7978 /* 2003.09.08: NaNs may now have coefficients, so next tests Inf only */ 7979 if (decNumberIsInfinite(dn)) { 7980 if (dn->digits!=1) { 7981 #if DECTRACE || DECVERB 7982 printf("Digits %ld (not 1) for an infinity.\n", (LI)dn->digits); 7983 #endif 7984 return 1;} 7985 if (*dn->lsu!=0) { 7986 #if DECTRACE || DECVERB 7987 printf("LSU %ld (not 0) for an infinity.\n", (LI)*dn->lsu); 7988 #endif 7989 decDumpAr('I', dn->lsu, D2U(dn->digits)); 7990 return 1;} 7991 } /* Inf */ 7992 /* 2002.12.26: negative NaNs can now appear through proposed IEEE */ 7993 /* concrete formats (decimal64, etc.). */ 7994 return 0; 7995 } 7996 7997 /* check the coefficient */ 7998 if (dn->digits<1 || dn->digits>DECNUMMAXP) { 7999 #if DECTRACE || DECVERB 8000 printf("Digits %ld in number.\n", (LI)dn->digits); 8001 #endif 8002 return 1;} 8003 8004 d=dn->digits; 8005 8006 for (up=dn->lsu; d>0; up++) { 8007 if (d>DECDPUN) maxuint=DECDPUNMAX; 8008 else { /* reached the msu */ 8009 maxuint=powers[d]-1; 8010 if (dn->digits>1 && *up<powers[d-1]) { 8011 #if DECTRACE || DECVERB 8012 printf("Leading 0 in number.\n"); 8013 uprv_decNumberShow(dn); 8014 #endif 8015 return 1;} 8016 } 8017 if (*up>maxuint) { 8018 #if DECTRACE || DECVERB 8019 printf("Bad Unit [%08lx] in %ld-digit number at offset %ld [maxuint %ld].\n", 8020 (LI)*up, (LI)dn->digits, (LI)(up-dn->lsu), (LI)maxuint); 8021 #endif 8022 return 1;} 8023 d-=DECDPUN; 8024 } 8025 8026 /* check the exponent. Note that input operands can have exponents */ 8027 /* which are out of the set->emin/set->emax and set->digits range */ 8028 /* (just as they can have more digits than set->digits). */ 8029 ae=dn->exponent+dn->digits-1; /* adjusted exponent */ 8030 emax=DECNUMMAXE; 8031 emin=DECNUMMINE; 8032 digits=DECNUMMAXP; 8033 if (ae<emin-(digits-1)) { 8034 #if DECTRACE || DECVERB 8035 printf("Adjusted exponent underflow [%ld].\n", (LI)ae); 8036 uprv_decNumberShow(dn); 8037 #endif 8038 return 1;} 8039 if (ae>+emax) { 8040 #if DECTRACE || DECVERB 8041 printf("Adjusted exponent overflow [%ld].\n", (LI)ae); 8042 uprv_decNumberShow(dn); 8043 #endif 8044 return 1;} 8045 8046 return 0; /* it's OK */ 8047 } /* decCheckNumber */ 8048 8049 /* ------------------------------------------------------------------ */ 8050 /* decCheckInexact -- check a normal finite inexact result has digits */ 8051 /* dn is the number to check */ 8052 /* set is the context (for status and precision) */ 8053 /* sets Invalid operation, etc., if some digits are missing */ 8054 /* [this check is not made for DECSUBSET compilation or when */ 8055 /* subnormal is not set] */ 8056 /* ------------------------------------------------------------------ */ 8057 static void decCheckInexact(const decNumber *dn, decContext *set) { 8058 #if !DECSUBSET && DECEXTFLAG 8059 if ((set->status & (DEC_Inexact|DEC_Subnormal))==DEC_Inexact 8060 && (set->digits!=dn->digits) && !(dn->bits & DECSPECIAL)) { 8061 #if DECTRACE || DECVERB 8062 printf("Insufficient digits [%ld] on normal Inexact result.\n", 8063 (LI)dn->digits); 8064 uprv_decNumberShow(dn); 8065 #endif 8066 uprv_decContextSetStatus(set, DEC_Invalid_operation); 8067 } 8068 #else 8069 /* next is a noop for quiet compiler */ 8070 if (dn!=NULL && dn->digits==0) set->status|=DEC_Invalid_operation; 8071 #endif 8072 return; 8073 } /* decCheckInexact */ 8074 #endif 8075 8076 #if DECALLOC 8077 #undef malloc 8078 #undef free 8079 /* ------------------------------------------------------------------ */ 8080 /* decMalloc -- accountable allocation routine */ 8081 /* n is the number of bytes to allocate */ 8082 /* */ 8083 /* Semantics is the same as the stdlib malloc routine, but bytes */ 8084 /* allocated are accounted for globally, and corruption fences are */ 8085 /* added before and after the 'actual' storage. */ 8086 /* ------------------------------------------------------------------ */ 8087 /* This routine allocates storage with an extra twelve bytes; 8 are */ 8088 /* at the start and hold: */ 8089 /* 0-3 the original length requested */ 8090 /* 4-7 buffer corruption detection fence (DECFENCE, x4) */ 8091 /* The 4 bytes at the end also hold a corruption fence (DECFENCE, x4) */ 8092 /* ------------------------------------------------------------------ */ 8093 static void *decMalloc(size_t n) { 8094 uInt size=n+12; /* true size */ 8095 void *alloc; /* -> allocated storage */ 8096 uByte *b, *b0; /* work */ 8097 uInt uiwork; /* for macros */ 8098 8099 alloc=malloc(size); /* -> allocated storage */ 8100 if (alloc==NULL) return NULL; /* out of strorage */ 8101 b0=(uByte *)alloc; /* as bytes */ 8102 decAllocBytes+=n; /* account for storage */ 8103 UBFROMUI(alloc, n); /* save n */ 8104 /* printf(" alloc ++ dAB: %ld (%ld)\n", (LI)decAllocBytes, (LI)n); */ 8105 for (b=b0+4; b<b0+8; b++) *b=DECFENCE; 8106 for (b=b0+n+8; b<b0+n+12; b++) *b=DECFENCE; 8107 return b0+8; /* -> play area */ 8108 } /* decMalloc */ 8109 8110 /* ------------------------------------------------------------------ */ 8111 /* decFree -- accountable free routine */ 8112 /* alloc is the storage to free */ 8113 /* */ 8114 /* Semantics is the same as the stdlib malloc routine, except that */ 8115 /* the global storage accounting is updated and the fences are */ 8116 /* checked to ensure that no routine has written 'out of bounds'. */ 8117 /* ------------------------------------------------------------------ */ 8118 /* This routine first checks that the fences have not been corrupted. */ 8119 /* It then frees the storage using the 'truw' storage address (that */ 8120 /* is, offset by 8). */ 8121 /* ------------------------------------------------------------------ */ 8122 static void decFree(void *alloc) { 8123 uInt n; /* original length */ 8124 uByte *b, *b0; /* work */ 8125 uInt uiwork; /* for macros */ 8126 8127 if (alloc==NULL) return; /* allowed; it's a nop */ 8128 b0=(uByte *)alloc; /* as bytes */ 8129 b0-=8; /* -> true start of storage */ 8130 n=UBTOUI(b0); /* lift length */ 8131 for (b=b0+4; b<b0+8; b++) if (*b!=DECFENCE) 8132 printf("=== Corrupt byte [%02x] at offset %d from %ld ===\n", *b, 8133 b-b0-8, (LI)b0); 8134 for (b=b0+n+8; b<b0+n+12; b++) if (*b!=DECFENCE) 8135 printf("=== Corrupt byte [%02x] at offset +%d from %ld, n=%ld ===\n", *b, 8136 b-b0-8, (LI)b0, (LI)n); 8137 free(b0); /* drop the storage */ 8138 decAllocBytes-=n; /* account for storage */ 8139 /* printf(" free -- dAB: %d (%d)\n", decAllocBytes, -n); */ 8140 } /* decFree */ 8141 #define malloc(a) decMalloc(a) 8142 #define free(a) decFree(a) 8143 #endif 8144
