1 /* IEEE floating point support routines, for GDB, the GNU Debugger. 2 Copyright 1991, 1994, 1999, 2000, 2003, 2005, 2006, 2010, 2012 3 Free Software Foundation, Inc. 4 5 This file is part of GDB. 6 7 This program is free software; you can redistribute it and/or modify 8 it under the terms of the GNU General Public License as published by 9 the Free Software Foundation; either version 2 of the License, or 10 (at your option) any later version. 11 12 This program is distributed in the hope that it will be useful, 13 but WITHOUT ANY WARRANTY; without even the implied warranty of 14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 GNU General Public License for more details. 16 17 You should have received a copy of the GNU General Public License 18 along with this program; if not, write to the Free Software 19 Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA. */ 20 21 /* This is needed to pick up the NAN macro on some systems. */ 22 #define _GNU_SOURCE 23 24 #ifdef HAVE_CONFIG_H 25 #include "config.h" 26 #endif 27 28 #include <math.h> 29 30 #ifdef HAVE_STRING_H 31 #include <string.h> 32 #endif 33 34 /* On some platforms, <float.h> provides DBL_QNAN. */ 35 #ifdef STDC_HEADERS 36 #include <float.h> 37 #endif 38 39 #include "ansidecl.h" 40 #include "libiberty.h" 41 #include "floatformat.h" 42 43 #ifndef INFINITY 44 #ifdef HUGE_VAL 45 #define INFINITY HUGE_VAL 46 #else 47 #define INFINITY (1.0 / 0.0) 48 #endif 49 #endif 50 51 #ifndef NAN 52 #ifdef DBL_QNAN 53 #define NAN DBL_QNAN 54 #else 55 #define NAN (0.0 / 0.0) 56 #endif 57 #endif 58 59 static int mant_bits_set (const struct floatformat *, const unsigned char *); 60 static unsigned long get_field (const unsigned char *, 61 enum floatformat_byteorders, 62 unsigned int, 63 unsigned int, 64 unsigned int); 65 static int floatformat_always_valid (const struct floatformat *fmt, 66 const void *from); 67 68 static int 69 floatformat_always_valid (const struct floatformat *fmt ATTRIBUTE_UNUSED, 70 const void *from ATTRIBUTE_UNUSED) 71 { 72 return 1; 73 } 74 75 /* The odds that CHAR_BIT will be anything but 8 are low enough that I'm not 76 going to bother with trying to muck around with whether it is defined in 77 a system header, what we do if not, etc. */ 78 #define FLOATFORMAT_CHAR_BIT 8 79 80 /* floatformats for IEEE half, single and double, big and little endian. */ 81 const struct floatformat floatformat_ieee_half_big = 82 { 83 floatformat_big, 16, 0, 1, 5, 15, 31, 6, 10, 84 floatformat_intbit_no, 85 "floatformat_ieee_half_big", 86 floatformat_always_valid, 87 NULL 88 }; 89 const struct floatformat floatformat_ieee_half_little = 90 { 91 floatformat_little, 16, 0, 1, 5, 15, 31, 6, 10, 92 floatformat_intbit_no, 93 "floatformat_ieee_half_little", 94 floatformat_always_valid, 95 NULL 96 }; 97 const struct floatformat floatformat_ieee_single_big = 98 { 99 floatformat_big, 32, 0, 1, 8, 127, 255, 9, 23, 100 floatformat_intbit_no, 101 "floatformat_ieee_single_big", 102 floatformat_always_valid, 103 NULL 104 }; 105 const struct floatformat floatformat_ieee_single_little = 106 { 107 floatformat_little, 32, 0, 1, 8, 127, 255, 9, 23, 108 floatformat_intbit_no, 109 "floatformat_ieee_single_little", 110 floatformat_always_valid, 111 NULL 112 }; 113 const struct floatformat floatformat_ieee_double_big = 114 { 115 floatformat_big, 64, 0, 1, 11, 1023, 2047, 12, 52, 116 floatformat_intbit_no, 117 "floatformat_ieee_double_big", 118 floatformat_always_valid, 119 NULL 120 }; 121 const struct floatformat floatformat_ieee_double_little = 122 { 123 floatformat_little, 64, 0, 1, 11, 1023, 2047, 12, 52, 124 floatformat_intbit_no, 125 "floatformat_ieee_double_little", 126 floatformat_always_valid, 127 NULL 128 }; 129 130 /* floatformat for IEEE double, little endian byte order, with big endian word 131 ordering, as on the ARM. */ 132 133 const struct floatformat floatformat_ieee_double_littlebyte_bigword = 134 { 135 floatformat_littlebyte_bigword, 64, 0, 1, 11, 1023, 2047, 12, 52, 136 floatformat_intbit_no, 137 "floatformat_ieee_double_littlebyte_bigword", 138 floatformat_always_valid, 139 NULL 140 }; 141 142 /* floatformat for VAX. Not quite IEEE, but close enough. */ 143 144 const struct floatformat floatformat_vax_f = 145 { 146 floatformat_vax, 32, 0, 1, 8, 129, 0, 9, 23, 147 floatformat_intbit_no, 148 "floatformat_vax_f", 149 floatformat_always_valid, 150 NULL 151 }; 152 const struct floatformat floatformat_vax_d = 153 { 154 floatformat_vax, 64, 0, 1, 8, 129, 0, 9, 55, 155 floatformat_intbit_no, 156 "floatformat_vax_d", 157 floatformat_always_valid, 158 NULL 159 }; 160 const struct floatformat floatformat_vax_g = 161 { 162 floatformat_vax, 64, 0, 1, 11, 1025, 0, 12, 52, 163 floatformat_intbit_no, 164 "floatformat_vax_g", 165 floatformat_always_valid, 166 NULL 167 }; 168 169 static int floatformat_i387_ext_is_valid (const struct floatformat *fmt, 170 const void *from); 171 172 static int 173 floatformat_i387_ext_is_valid (const struct floatformat *fmt, const void *from) 174 { 175 /* In the i387 double-extended format, if the exponent is all ones, 176 then the integer bit must be set. If the exponent is neither 0 177 nor ~0, the intbit must also be set. Only if the exponent is 178 zero can it be zero, and then it must be zero. */ 179 unsigned long exponent, int_bit; 180 const unsigned char *ufrom = (const unsigned char *) from; 181 182 exponent = get_field (ufrom, fmt->byteorder, fmt->totalsize, 183 fmt->exp_start, fmt->exp_len); 184 int_bit = get_field (ufrom, fmt->byteorder, fmt->totalsize, 185 fmt->man_start, 1); 186 187 if ((exponent == 0) != (int_bit == 0)) 188 return 0; 189 else 190 return 1; 191 } 192 193 const struct floatformat floatformat_i387_ext = 194 { 195 floatformat_little, 80, 0, 1, 15, 0x3fff, 0x7fff, 16, 64, 196 floatformat_intbit_yes, 197 "floatformat_i387_ext", 198 floatformat_i387_ext_is_valid, 199 NULL 200 }; 201 const struct floatformat floatformat_m68881_ext = 202 { 203 /* Note that the bits from 16 to 31 are unused. */ 204 floatformat_big, 96, 0, 1, 15, 0x3fff, 0x7fff, 32, 64, 205 floatformat_intbit_yes, 206 "floatformat_m68881_ext", 207 floatformat_always_valid, 208 NULL 209 }; 210 const struct floatformat floatformat_i960_ext = 211 { 212 /* Note that the bits from 0 to 15 are unused. */ 213 floatformat_little, 96, 16, 17, 15, 0x3fff, 0x7fff, 32, 64, 214 floatformat_intbit_yes, 215 "floatformat_i960_ext", 216 floatformat_always_valid, 217 NULL 218 }; 219 const struct floatformat floatformat_m88110_ext = 220 { 221 floatformat_big, 80, 0, 1, 15, 0x3fff, 0x7fff, 16, 64, 222 floatformat_intbit_yes, 223 "floatformat_m88110_ext", 224 floatformat_always_valid, 225 NULL 226 }; 227 const struct floatformat floatformat_m88110_harris_ext = 228 { 229 /* Harris uses raw format 128 bytes long, but the number is just an ieee 230 double, and the last 64 bits are wasted. */ 231 floatformat_big,128, 0, 1, 11, 0x3ff, 0x7ff, 12, 52, 232 floatformat_intbit_no, 233 "floatformat_m88110_ext_harris", 234 floatformat_always_valid, 235 NULL 236 }; 237 const struct floatformat floatformat_arm_ext_big = 238 { 239 /* Bits 1 to 16 are unused. */ 240 floatformat_big, 96, 0, 17, 15, 0x3fff, 0x7fff, 32, 64, 241 floatformat_intbit_yes, 242 "floatformat_arm_ext_big", 243 floatformat_always_valid, 244 NULL 245 }; 246 const struct floatformat floatformat_arm_ext_littlebyte_bigword = 247 { 248 /* Bits 1 to 16 are unused. */ 249 floatformat_littlebyte_bigword, 96, 0, 17, 15, 0x3fff, 0x7fff, 32, 64, 250 floatformat_intbit_yes, 251 "floatformat_arm_ext_littlebyte_bigword", 252 floatformat_always_valid, 253 NULL 254 }; 255 const struct floatformat floatformat_ia64_spill_big = 256 { 257 floatformat_big, 128, 0, 1, 17, 65535, 0x1ffff, 18, 64, 258 floatformat_intbit_yes, 259 "floatformat_ia64_spill_big", 260 floatformat_always_valid, 261 NULL 262 }; 263 const struct floatformat floatformat_ia64_spill_little = 264 { 265 floatformat_little, 128, 0, 1, 17, 65535, 0x1ffff, 18, 64, 266 floatformat_intbit_yes, 267 "floatformat_ia64_spill_little", 268 floatformat_always_valid, 269 NULL 270 }; 271 const struct floatformat floatformat_ia64_quad_big = 272 { 273 floatformat_big, 128, 0, 1, 15, 16383, 0x7fff, 16, 112, 274 floatformat_intbit_no, 275 "floatformat_ia64_quad_big", 276 floatformat_always_valid, 277 NULL 278 }; 279 const struct floatformat floatformat_ia64_quad_little = 280 { 281 floatformat_little, 128, 0, 1, 15, 16383, 0x7fff, 16, 112, 282 floatformat_intbit_no, 283 "floatformat_ia64_quad_little", 284 floatformat_always_valid, 285 NULL 286 }; 287 288 static int 289 floatformat_ibm_long_double_is_valid (const struct floatformat *fmt, 290 const void *from) 291 { 292 const unsigned char *ufrom = (const unsigned char *) from; 293 const struct floatformat *hfmt = fmt->split_half; 294 long top_exp, bot_exp; 295 int top_nan = 0; 296 297 top_exp = get_field (ufrom, hfmt->byteorder, hfmt->totalsize, 298 hfmt->exp_start, hfmt->exp_len); 299 bot_exp = get_field (ufrom + 8, hfmt->byteorder, hfmt->totalsize, 300 hfmt->exp_start, hfmt->exp_len); 301 302 if ((unsigned long) top_exp == hfmt->exp_nan) 303 top_nan = mant_bits_set (hfmt, ufrom); 304 305 /* A NaN is valid with any low part. */ 306 if (top_nan) 307 return 1; 308 309 /* An infinity, zero or denormal requires low part 0 (positive or 310 negative). */ 311 if ((unsigned long) top_exp == hfmt->exp_nan || top_exp == 0) 312 { 313 if (bot_exp != 0) 314 return 0; 315 316 return !mant_bits_set (hfmt, ufrom + 8); 317 } 318 319 /* The top part is now a finite normal value. The long double value 320 is the sum of the two parts, and the top part must equal the 321 result of rounding the long double value to nearest double. Thus 322 the bottom part must be <= 0.5ulp of the top part in absolute 323 value, and if it is < 0.5ulp then the long double is definitely 324 valid. */ 325 if (bot_exp < top_exp - 53) 326 return 1; 327 if (bot_exp > top_exp - 53 && bot_exp != 0) 328 return 0; 329 if (bot_exp == 0) 330 { 331 /* The bottom part is 0 or denormal. Determine which, and if 332 denormal the first two set bits. */ 333 int first_bit = -1, second_bit = -1, cur_bit; 334 for (cur_bit = 0; (unsigned int) cur_bit < hfmt->man_len; cur_bit++) 335 if (get_field (ufrom + 8, hfmt->byteorder, hfmt->totalsize, 336 hfmt->man_start + cur_bit, 1)) 337 { 338 if (first_bit == -1) 339 first_bit = cur_bit; 340 else 341 { 342 second_bit = cur_bit; 343 break; 344 } 345 } 346 /* Bottom part 0 is OK. */ 347 if (first_bit == -1) 348 return 1; 349 /* The real exponent of the bottom part is -first_bit. */ 350 if (-first_bit < top_exp - 53) 351 return 1; 352 if (-first_bit > top_exp - 53) 353 return 0; 354 /* The bottom part is at least 0.5ulp of the top part. For this 355 to be OK, the bottom part must be exactly 0.5ulp (i.e. no 356 more bits set) and the top part must have last bit 0. */ 357 if (second_bit != -1) 358 return 0; 359 return !get_field (ufrom, hfmt->byteorder, hfmt->totalsize, 360 hfmt->man_start + hfmt->man_len - 1, 1); 361 } 362 else 363 { 364 /* The bottom part is at least 0.5ulp of the top part. For this 365 to be OK, it must be exactly 0.5ulp (i.e. no explicit bits 366 set) and the top part must have last bit 0. */ 367 if (get_field (ufrom, hfmt->byteorder, hfmt->totalsize, 368 hfmt->man_start + hfmt->man_len - 1, 1)) 369 return 0; 370 return !mant_bits_set (hfmt, ufrom + 8); 371 } 372 } 373 374 const struct floatformat floatformat_ibm_long_double_big = 375 { 376 floatformat_big, 128, 0, 1, 11, 1023, 2047, 12, 52, 377 floatformat_intbit_no, 378 "floatformat_ibm_long_double_big", 379 floatformat_ibm_long_double_is_valid, 380 &floatformat_ieee_double_big 381 }; 382 383 const struct floatformat floatformat_ibm_long_double_little = 384 { 385 floatformat_little, 128, 0, 1, 11, 1023, 2047, 12, 52, 386 floatformat_intbit_no, 387 "floatformat_ibm_long_double_little", 388 floatformat_ibm_long_double_is_valid, 389 &floatformat_ieee_double_little 390 }; 391 392 394 #ifndef min 395 #define min(a, b) ((a) < (b) ? (a) : (b)) 396 #endif 397 398 /* Return 1 if any bits are explicitly set in the mantissa of UFROM, 399 format FMT, 0 otherwise. */ 400 static int 401 mant_bits_set (const struct floatformat *fmt, const unsigned char *ufrom) 402 { 403 unsigned int mant_bits, mant_off; 404 int mant_bits_left; 405 406 mant_off = fmt->man_start; 407 mant_bits_left = fmt->man_len; 408 while (mant_bits_left > 0) 409 { 410 mant_bits = min (mant_bits_left, 32); 411 412 if (get_field (ufrom, fmt->byteorder, fmt->totalsize, 413 mant_off, mant_bits) != 0) 414 return 1; 415 416 mant_off += mant_bits; 417 mant_bits_left -= mant_bits; 418 } 419 return 0; 420 } 421 422 /* Extract a field which starts at START and is LEN bits long. DATA and 423 TOTAL_LEN are the thing we are extracting it from, in byteorder ORDER. */ 424 static unsigned long 425 get_field (const unsigned char *data, enum floatformat_byteorders order, 426 unsigned int total_len, unsigned int start, unsigned int len) 427 { 428 unsigned long result = 0; 429 unsigned int cur_byte; 430 int lo_bit, hi_bit, cur_bitshift = 0; 431 int nextbyte = (order == floatformat_little) ? 1 : -1; 432 433 /* Start is in big-endian bit order! Fix that first. */ 434 start = total_len - (start + len); 435 436 /* Start at the least significant part of the field. */ 437 if (order == floatformat_little) 438 cur_byte = start / FLOATFORMAT_CHAR_BIT; 439 else 440 cur_byte = (total_len - start - 1) / FLOATFORMAT_CHAR_BIT; 441 442 lo_bit = start % FLOATFORMAT_CHAR_BIT; 443 hi_bit = min (lo_bit + len, FLOATFORMAT_CHAR_BIT); 444 445 do 446 { 447 unsigned int shifted = *(data + cur_byte) >> lo_bit; 448 unsigned int bits = hi_bit - lo_bit; 449 unsigned int mask = (1 << bits) - 1; 450 result |= (shifted & mask) << cur_bitshift; 451 len -= bits; 452 cur_bitshift += bits; 453 cur_byte += nextbyte; 454 lo_bit = 0; 455 hi_bit = min (len, FLOATFORMAT_CHAR_BIT); 456 } 457 while (len != 0); 458 459 return result; 460 } 461 462 /* Convert from FMT to a double. 463 FROM is the address of the extended float. 464 Store the double in *TO. */ 465 466 void 467 floatformat_to_double (const struct floatformat *fmt, 468 const void *from, double *to) 469 { 470 const unsigned char *ufrom = (const unsigned char *) from; 471 double dto; 472 long exponent; 473 unsigned long mant; 474 unsigned int mant_bits, mant_off; 475 int mant_bits_left; 476 477 /* Split values are not handled specially, since the top half has 478 the correctly rounded double value (in the only supported case of 479 split values). */ 480 481 exponent = get_field (ufrom, fmt->byteorder, fmt->totalsize, 482 fmt->exp_start, fmt->exp_len); 483 484 /* If the exponent indicates a NaN, we don't have information to 485 decide what to do. So we handle it like IEEE, except that we 486 don't try to preserve the type of NaN. FIXME. */ 487 if ((unsigned long) exponent == fmt->exp_nan) 488 { 489 int nan = mant_bits_set (fmt, ufrom); 490 491 /* On certain systems (such as GNU/Linux), the use of the 492 INFINITY macro below may generate a warning that can not be 493 silenced due to a bug in GCC (PR preprocessor/11931). The 494 preprocessor fails to recognise the __extension__ keyword in 495 conjunction with the GNU/C99 extension for hexadecimal 496 floating point constants and will issue a warning when 497 compiling with -pedantic. */ 498 if (nan) 499 dto = NAN; 500 else 501 dto = INFINITY; 502 503 if (get_field (ufrom, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1)) 504 dto = -dto; 505 506 *to = dto; 507 508 return; 509 } 510 511 mant_bits_left = fmt->man_len; 512 mant_off = fmt->man_start; 513 dto = 0.0; 514 515 /* Build the result algebraically. Might go infinite, underflow, etc; 516 who cares. */ 517 518 /* For denorms use minimum exponent. */ 519 if (exponent == 0) 520 exponent = 1 - fmt->exp_bias; 521 else 522 { 523 exponent -= fmt->exp_bias; 524 525 /* If this format uses a hidden bit, explicitly add it in now. 526 Otherwise, increment the exponent by one to account for the 527 integer bit. */ 528 529 if (fmt->intbit == floatformat_intbit_no) 530 dto = ldexp (1.0, exponent); 531 else 532 exponent++; 533 } 534 535 while (mant_bits_left > 0) 536 { 537 mant_bits = min (mant_bits_left, 32); 538 539 mant = get_field (ufrom, fmt->byteorder, fmt->totalsize, 540 mant_off, mant_bits); 541 542 dto += ldexp ((double) mant, exponent - mant_bits); 543 exponent -= mant_bits; 544 mant_off += mant_bits; 545 mant_bits_left -= mant_bits; 546 } 547 548 /* Negate it if negative. */ 549 if (get_field (ufrom, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1)) 550 dto = -dto; 551 *to = dto; 552 } 553 554 static void put_field (unsigned char *, enum floatformat_byteorders, 556 unsigned int, 557 unsigned int, 558 unsigned int, 559 unsigned long); 560 561 /* Set a field which starts at START and is LEN bits long. DATA and 562 TOTAL_LEN are the thing we are extracting it from, in byteorder ORDER. */ 563 static void 564 put_field (unsigned char *data, enum floatformat_byteorders order, 565 unsigned int total_len, unsigned int start, unsigned int len, 566 unsigned long stuff_to_put) 567 { 568 unsigned int cur_byte; 569 int lo_bit, hi_bit; 570 int nextbyte = (order == floatformat_little) ? 1 : -1; 571 572 /* Start is in big-endian bit order! Fix that first. */ 573 start = total_len - (start + len); 574 575 /* Start at the least significant part of the field. */ 576 if (order == floatformat_little) 577 cur_byte = start / FLOATFORMAT_CHAR_BIT; 578 else 579 cur_byte = (total_len - start - 1) / FLOATFORMAT_CHAR_BIT; 580 581 lo_bit = start % FLOATFORMAT_CHAR_BIT; 582 hi_bit = min (lo_bit + len, FLOATFORMAT_CHAR_BIT); 583 584 do 585 { 586 unsigned char *byte_ptr = data + cur_byte; 587 unsigned int bits = hi_bit - lo_bit; 588 unsigned int mask = ((1 << bits) - 1) << lo_bit; 589 *byte_ptr = (*byte_ptr & ~mask) | ((stuff_to_put << lo_bit) & mask); 590 stuff_to_put >>= bits; 591 len -= bits; 592 cur_byte += nextbyte; 593 lo_bit = 0; 594 hi_bit = min (len, FLOATFORMAT_CHAR_BIT); 595 } 596 while (len != 0); 597 } 598 599 /* The converse: convert the double *FROM to an extended float 600 and store where TO points. Neither FROM nor TO have any alignment 601 restrictions. */ 602 603 void 604 floatformat_from_double (const struct floatformat *fmt, 605 const double *from, void *to) 606 { 607 double dfrom; 608 int exponent; 609 double mant; 610 unsigned int mant_bits, mant_off; 611 int mant_bits_left; 612 unsigned char *uto = (unsigned char *) to; 613 614 dfrom = *from; 615 memset (uto, 0, fmt->totalsize / FLOATFORMAT_CHAR_BIT); 616 617 /* Split values are not handled specially, since a bottom half of 618 zero is correct for any value representable as double (in the 619 only supported case of split values). */ 620 621 /* If negative, set the sign bit. */ 622 if (dfrom < 0) 623 { 624 put_field (uto, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1, 1); 625 dfrom = -dfrom; 626 } 627 628 if (dfrom == 0) 629 { 630 /* 0.0. */ 631 return; 632 } 633 634 if (dfrom != dfrom) 635 { 636 /* NaN. */ 637 put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start, 638 fmt->exp_len, fmt->exp_nan); 639 /* Be sure it's not infinity, but NaN value is irrelevant. */ 640 put_field (uto, fmt->byteorder, fmt->totalsize, fmt->man_start, 641 32, 1); 642 return; 643 } 644 645 if (dfrom + dfrom == dfrom) 646 { 647 /* This can only happen for an infinite value (or zero, which we 648 already handled above). */ 649 put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start, 650 fmt->exp_len, fmt->exp_nan); 651 return; 652 } 653 654 mant = frexp (dfrom, &exponent); 655 if (exponent + fmt->exp_bias - 1 > 0) 656 put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start, 657 fmt->exp_len, exponent + fmt->exp_bias - 1); 658 else 659 { 660 /* Handle a denormalized number. FIXME: What should we do for 661 non-IEEE formats? */ 662 put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start, 663 fmt->exp_len, 0); 664 mant = ldexp (mant, exponent + fmt->exp_bias - 1); 665 } 666 667 mant_bits_left = fmt->man_len; 668 mant_off = fmt->man_start; 669 while (mant_bits_left > 0) 670 { 671 unsigned long mant_long; 672 mant_bits = mant_bits_left < 32 ? mant_bits_left : 32; 673 674 mant *= 4294967296.0; 675 mant_long = (unsigned long)mant; 676 mant -= mant_long; 677 678 /* If the integer bit is implicit, and we are not creating a 679 denormalized number, then we need to discard it. */ 680 if ((unsigned int) mant_bits_left == fmt->man_len 681 && fmt->intbit == floatformat_intbit_no 682 && exponent + fmt->exp_bias - 1 > 0) 683 { 684 mant_long &= 0x7fffffff; 685 mant_bits -= 1; 686 } 687 else if (mant_bits < 32) 688 { 689 /* The bits we want are in the most significant MANT_BITS bits of 690 mant_long. Move them to the least significant. */ 691 mant_long >>= 32 - mant_bits; 692 } 693 694 put_field (uto, fmt->byteorder, fmt->totalsize, 695 mant_off, mant_bits, mant_long); 696 mant_off += mant_bits; 697 mant_bits_left -= mant_bits; 698 } 699 } 700 701 /* Return non-zero iff the data at FROM is a valid number in format FMT. */ 702 703 int 704 floatformat_is_valid (const struct floatformat *fmt, const void *from) 705 { 706 return fmt->is_valid (fmt, from); 707 } 708 709 710 #ifdef IEEE_DEBUG 711 712 #include <stdio.h> 713 714 /* This is to be run on a host which uses IEEE floating point. */ 715 716 void 717 ieee_test (double n) 718 { 719 double result; 720 721 floatformat_to_double (&floatformat_ieee_double_little, &n, &result); 722 if ((n != result && (! isnan (n) || ! isnan (result))) 723 || (n < 0 && result >= 0) 724 || (n >= 0 && result < 0)) 725 printf ("Differ(to): %.20g -> %.20g\n", n, result); 726 727 floatformat_from_double (&floatformat_ieee_double_little, &n, &result); 728 if ((n != result && (! isnan (n) || ! isnan (result))) 729 || (n < 0 && result >= 0) 730 || (n >= 0 && result < 0)) 731 printf ("Differ(from): %.20g -> %.20g\n", n, result); 732 733 #if 0 734 { 735 char exten[16]; 736 737 floatformat_from_double (&floatformat_m68881_ext, &n, exten); 738 floatformat_to_double (&floatformat_m68881_ext, exten, &result); 739 if (n != result) 740 printf ("Differ(to+from): %.20g -> %.20g\n", n, result); 741 } 742 #endif 743 744 #if IEEE_DEBUG > 1 745 /* This is to be run on a host which uses 68881 format. */ 746 { 747 long double ex = *(long double *)exten; 748 if (ex != n) 749 printf ("Differ(from vs. extended): %.20g\n", n); 750 } 751 #endif 752 } 753 754 int 755 main (void) 756 { 757 ieee_test (0.0); 758 ieee_test (0.5); 759 ieee_test (1.1); 760 ieee_test (256.0); 761 ieee_test (0.12345); 762 ieee_test (234235.78907234); 763 ieee_test (-512.0); 764 ieee_test (-0.004321); 765 ieee_test (1.2E-70); 766 ieee_test (1.2E-316); 767 ieee_test (4.9406564584124654E-324); 768 ieee_test (- 4.9406564584124654E-324); 769 ieee_test (- 0.0); 770 ieee_test (- INFINITY); 771 ieee_test (- NAN); 772 ieee_test (INFINITY); 773 ieee_test (NAN); 774 return 0; 775 } 776 #endif 777
