1 /* atof_ieee.c - turn a Flonum into an IEEE floating point number 2 Copyright (C) 1987-2016 Free Software Foundation, Inc. 3 4 This file is part of GAS, the GNU Assembler. 5 6 GAS is free software; you can redistribute it and/or modify 7 it under the terms of the GNU General Public License as published by 8 the Free Software Foundation; either version 3, or (at your option) 9 any later version. 10 11 GAS is distributed in the hope that it will be useful, 12 but WITHOUT ANY WARRANTY; without even the implied warranty of 13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 GNU General Public License for more details. 15 16 You should have received a copy of the GNU General Public License 17 along with GAS; see the file COPYING. If not, write to the Free 18 Software Foundation, 51 Franklin Street - Fifth Floor, Boston, MA 19 02110-1301, USA. */ 20 21 #include "as.h" 22 23 /* Flonums returned here. */ 24 extern FLONUM_TYPE generic_floating_point_number; 25 26 /* Precision in LittleNums. */ 27 /* Don't count the gap in the m68k extended precision format. */ 28 #define MAX_PRECISION 5 29 #define F_PRECISION 2 30 #define D_PRECISION 4 31 #define X_PRECISION 5 32 #define P_PRECISION 5 33 34 /* Length in LittleNums of guard bits. */ 35 #define GUARD 2 36 37 #ifndef TC_LARGEST_EXPONENT_IS_NORMAL 38 #define TC_LARGEST_EXPONENT_IS_NORMAL(PRECISION) 0 39 #endif 40 41 static const unsigned long mask[] = 42 { 43 0x00000000, 44 0x00000001, 45 0x00000003, 46 0x00000007, 47 0x0000000f, 48 0x0000001f, 49 0x0000003f, 50 0x0000007f, 51 0x000000ff, 52 0x000001ff, 53 0x000003ff, 54 0x000007ff, 55 0x00000fff, 56 0x00001fff, 57 0x00003fff, 58 0x00007fff, 59 0x0000ffff, 60 0x0001ffff, 61 0x0003ffff, 62 0x0007ffff, 63 0x000fffff, 64 0x001fffff, 65 0x003fffff, 66 0x007fffff, 67 0x00ffffff, 68 0x01ffffff, 69 0x03ffffff, 70 0x07ffffff, 71 0x0fffffff, 72 0x1fffffff, 73 0x3fffffff, 74 0x7fffffff, 75 0xffffffff, 76 }; 77 78 static int bits_left_in_littlenum; 80 static int littlenums_left; 81 static LITTLENUM_TYPE *littlenum_pointer; 82 83 static int 84 next_bits (int number_of_bits) 85 { 86 int return_value; 87 88 if (!littlenums_left) 89 return 0; 90 91 if (number_of_bits >= bits_left_in_littlenum) 92 { 93 return_value = mask[bits_left_in_littlenum] & *littlenum_pointer; 94 number_of_bits -= bits_left_in_littlenum; 95 return_value <<= number_of_bits; 96 97 if (--littlenums_left) 98 { 99 bits_left_in_littlenum = LITTLENUM_NUMBER_OF_BITS - number_of_bits; 100 --littlenum_pointer; 101 return_value |= 102 (*littlenum_pointer >> bits_left_in_littlenum) 103 & mask[number_of_bits]; 104 } 105 } 106 else 107 { 108 bits_left_in_littlenum -= number_of_bits; 109 return_value = 110 mask[number_of_bits] & (*littlenum_pointer >> bits_left_in_littlenum); 111 } 112 return return_value; 113 } 114 115 /* Num had better be less than LITTLENUM_NUMBER_OF_BITS. */ 116 117 static void 118 unget_bits (int num) 119 { 120 if (!littlenums_left) 121 { 122 ++littlenum_pointer; 123 ++littlenums_left; 124 bits_left_in_littlenum = num; 125 } 126 else if (bits_left_in_littlenum + num > LITTLENUM_NUMBER_OF_BITS) 127 { 128 bits_left_in_littlenum = 129 num - (LITTLENUM_NUMBER_OF_BITS - bits_left_in_littlenum); 130 ++littlenum_pointer; 131 ++littlenums_left; 132 } 133 else 134 bits_left_in_littlenum += num; 135 } 136 137 static void 138 make_invalid_floating_point_number (LITTLENUM_TYPE *words) 139 { 140 as_bad (_("cannot create floating-point number")); 141 /* Zero the leftmost bit. */ 142 words[0] = (LITTLENUM_TYPE) ((unsigned) -1) >> 1; 143 words[1] = (LITTLENUM_TYPE) -1; 144 words[2] = (LITTLENUM_TYPE) -1; 145 words[3] = (LITTLENUM_TYPE) -1; 146 words[4] = (LITTLENUM_TYPE) -1; 147 words[5] = (LITTLENUM_TYPE) -1; 148 } 149 150 /* Warning: This returns 16-bit LITTLENUMs. It is up to the caller to 152 figure out any alignment problems and to conspire for the 153 bytes/word to be emitted in the right order. Bigendians beware! */ 154 155 /* Note that atof-ieee always has X and P precisions enabled. it is up 156 to md_atof to filter them out if the target machine does not support 157 them. */ 158 159 /* Returns pointer past text consumed. */ 160 161 char * 162 atof_ieee (char *str, /* Text to convert to binary. */ 163 int what_kind, /* 'd', 'f', 'x', 'p'. */ 164 LITTLENUM_TYPE *words) /* Build the binary here. */ 165 { 166 /* Extra bits for zeroed low-order bits. 167 The 1st MAX_PRECISION are zeroed, the last contain flonum bits. */ 168 static LITTLENUM_TYPE bits[MAX_PRECISION + MAX_PRECISION + GUARD]; 169 char *return_value; 170 /* Number of 16-bit words in the format. */ 171 int precision; 172 long exponent_bits; 173 FLONUM_TYPE save_gen_flonum; 174 175 /* We have to save the generic_floating_point_number because it 176 contains storage allocation about the array of LITTLENUMs where 177 the value is actually stored. We will allocate our own array of 178 littlenums below, but have to restore the global one on exit. */ 179 save_gen_flonum = generic_floating_point_number; 180 181 return_value = str; 182 generic_floating_point_number.low = bits + MAX_PRECISION; 183 generic_floating_point_number.high = NULL; 184 generic_floating_point_number.leader = NULL; 185 generic_floating_point_number.exponent = 0; 186 generic_floating_point_number.sign = '\0'; 187 188 /* Use more LittleNums than seems necessary: the highest flonum may 189 have 15 leading 0 bits, so could be useless. */ 190 191 memset (bits, '\0', sizeof (LITTLENUM_TYPE) * MAX_PRECISION); 192 193 switch (what_kind) 194 { 195 case 'f': 196 case 'F': 197 case 's': 198 case 'S': 199 precision = F_PRECISION; 200 exponent_bits = 8; 201 break; 202 203 case 'd': 204 case 'D': 205 case 'r': 206 case 'R': 207 precision = D_PRECISION; 208 exponent_bits = 11; 209 break; 210 211 case 'x': 212 case 'X': 213 case 'e': 214 case 'E': 215 precision = X_PRECISION; 216 exponent_bits = 15; 217 break; 218 219 case 'p': 220 case 'P': 221 precision = P_PRECISION; 222 exponent_bits = -1; 223 break; 224 225 default: 226 make_invalid_floating_point_number (words); 227 return (NULL); 228 } 229 230 generic_floating_point_number.high 231 = generic_floating_point_number.low + precision - 1 + GUARD; 232 233 if (atof_generic (&return_value, ".", EXP_CHARS, 234 &generic_floating_point_number)) 235 { 236 make_invalid_floating_point_number (words); 237 return NULL; 238 } 239 gen_to_words (words, precision, exponent_bits); 240 241 /* Restore the generic_floating_point_number's storage alloc (and 242 everything else). */ 243 generic_floating_point_number = save_gen_flonum; 244 245 return return_value; 246 } 247 248 /* Turn generic_floating_point_number into a real float/double/extended. */ 249 250 int 251 gen_to_words (LITTLENUM_TYPE *words, int precision, long exponent_bits) 252 { 253 int return_value = 0; 254 255 long exponent_1; 256 long exponent_2; 257 long exponent_3; 258 long exponent_4; 259 int exponent_skippage; 260 LITTLENUM_TYPE word1; 261 LITTLENUM_TYPE *lp; 262 LITTLENUM_TYPE *words_end; 263 264 words_end = words + precision; 265 #ifdef TC_M68K 266 if (precision == X_PRECISION) 267 /* On the m68k the extended precision format has a gap of 16 bits 268 between the exponent and the mantissa. */ 269 words_end++; 270 #endif 271 272 if (generic_floating_point_number.low > generic_floating_point_number.leader) 273 { 274 /* 0.0e0 seen. */ 275 if (generic_floating_point_number.sign == '+') 276 words[0] = 0x0000; 277 else 278 words[0] = 0x8000; 279 memset (&words[1], '\0', 280 (words_end - words - 1) * sizeof (LITTLENUM_TYPE)); 281 return return_value; 282 } 283 284 /* NaN: Do the right thing. */ 285 if (generic_floating_point_number.sign == 0) 286 { 287 if (TC_LARGEST_EXPONENT_IS_NORMAL (precision)) 288 as_warn (_("NaNs are not supported by this target\n")); 289 if (precision == F_PRECISION) 290 { 291 words[0] = 0x7fff; 292 words[1] = 0xffff; 293 } 294 else if (precision == X_PRECISION) 295 { 296 #ifdef TC_M68K 297 words[0] = 0x7fff; 298 words[1] = 0; 299 words[2] = 0xffff; 300 words[3] = 0xffff; 301 words[4] = 0xffff; 302 words[5] = 0xffff; 303 #else /* ! TC_M68K */ 304 #ifdef TC_I386 305 words[0] = 0xffff; 306 words[1] = 0xc000; 307 words[2] = 0; 308 words[3] = 0; 309 words[4] = 0; 310 #else /* ! TC_I386 */ 311 abort (); 312 #endif /* ! TC_I386 */ 313 #endif /* ! TC_M68K */ 314 } 315 else 316 { 317 words[0] = 0x7fff; 318 words[1] = 0xffff; 319 words[2] = 0xffff; 320 words[3] = 0xffff; 321 } 322 return return_value; 323 } 324 else if (generic_floating_point_number.sign == 'P') 325 { 326 if (TC_LARGEST_EXPONENT_IS_NORMAL (precision)) 327 as_warn (_("Infinities are not supported by this target\n")); 328 329 /* +INF: Do the right thing. */ 330 if (precision == F_PRECISION) 331 { 332 words[0] = 0x7f80; 333 words[1] = 0; 334 } 335 else if (precision == X_PRECISION) 336 { 337 #ifdef TC_M68K 338 words[0] = 0x7fff; 339 words[1] = 0; 340 words[2] = 0; 341 words[3] = 0; 342 words[4] = 0; 343 words[5] = 0; 344 #else /* ! TC_M68K */ 345 #ifdef TC_I386 346 words[0] = 0x7fff; 347 words[1] = 0x8000; 348 words[2] = 0; 349 words[3] = 0; 350 words[4] = 0; 351 #else /* ! TC_I386 */ 352 abort (); 353 #endif /* ! TC_I386 */ 354 #endif /* ! TC_M68K */ 355 } 356 else 357 { 358 words[0] = 0x7ff0; 359 words[1] = 0; 360 words[2] = 0; 361 words[3] = 0; 362 } 363 return return_value; 364 } 365 else if (generic_floating_point_number.sign == 'N') 366 { 367 if (TC_LARGEST_EXPONENT_IS_NORMAL (precision)) 368 as_warn (_("Infinities are not supported by this target\n")); 369 370 /* Negative INF. */ 371 if (precision == F_PRECISION) 372 { 373 words[0] = 0xff80; 374 words[1] = 0x0; 375 } 376 else if (precision == X_PRECISION) 377 { 378 #ifdef TC_M68K 379 words[0] = 0xffff; 380 words[1] = 0; 381 words[2] = 0; 382 words[3] = 0; 383 words[4] = 0; 384 words[5] = 0; 385 #else /* ! TC_M68K */ 386 #ifdef TC_I386 387 words[0] = 0xffff; 388 words[1] = 0x8000; 389 words[2] = 0; 390 words[3] = 0; 391 words[4] = 0; 392 #else /* ! TC_I386 */ 393 abort (); 394 #endif /* ! TC_I386 */ 395 #endif /* ! TC_M68K */ 396 } 397 else 398 { 399 words[0] = 0xfff0; 400 words[1] = 0x0; 401 words[2] = 0x0; 402 words[3] = 0x0; 403 } 404 return return_value; 405 } 406 407 /* The floating point formats we support have: 408 Bit 15 is sign bit. 409 Bits 14:n are excess-whatever exponent. 410 Bits n-1:0 (if any) are most significant bits of fraction. 411 Bits 15:0 of the next word(s) are the next most significant bits. 412 413 So we need: number of bits of exponent, number of bits of 414 mantissa. */ 415 bits_left_in_littlenum = LITTLENUM_NUMBER_OF_BITS; 416 littlenum_pointer = generic_floating_point_number.leader; 417 littlenums_left = (1 418 + generic_floating_point_number.leader 419 - generic_floating_point_number.low); 420 421 /* Seek (and forget) 1st significant bit. */ 422 for (exponent_skippage = 0; !next_bits (1); ++exponent_skippage); 423 exponent_1 = (generic_floating_point_number.exponent 424 + generic_floating_point_number.leader 425 + 1 426 - generic_floating_point_number.low); 427 428 /* Radix LITTLENUM_RADIX, point just higher than 429 generic_floating_point_number.leader. */ 430 exponent_2 = exponent_1 * LITTLENUM_NUMBER_OF_BITS; 431 432 /* Radix 2. */ 433 exponent_3 = exponent_2 - exponent_skippage; 434 435 /* Forget leading zeros, forget 1st bit. */ 436 exponent_4 = exponent_3 + ((1 << (exponent_bits - 1)) - 2); 437 438 /* Offset exponent. */ 439 lp = words; 440 441 /* Word 1. Sign, exponent and perhaps high bits. */ 442 word1 = ((generic_floating_point_number.sign == '+') 443 ? 0 444 : (1 << (LITTLENUM_NUMBER_OF_BITS - 1))); 445 446 /* Assume 2's complement integers. */ 447 if (exponent_4 <= 0) 448 { 449 int prec_bits; 450 int num_bits; 451 452 unget_bits (1); 453 num_bits = -exponent_4; 454 prec_bits = 455 LITTLENUM_NUMBER_OF_BITS * precision - (exponent_bits + 1 + num_bits); 456 #ifdef TC_I386 457 if (precision == X_PRECISION && exponent_bits == 15) 458 { 459 /* On the i386 a denormalized extended precision float is 460 shifted down by one, effectively decreasing the exponent 461 bias by one. */ 462 prec_bits -= 1; 463 num_bits += 1; 464 } 465 #endif 466 467 if (num_bits >= LITTLENUM_NUMBER_OF_BITS - exponent_bits) 468 { 469 /* Bigger than one littlenum. */ 470 num_bits -= (LITTLENUM_NUMBER_OF_BITS - 1) - exponent_bits; 471 *lp++ = word1; 472 if (num_bits + exponent_bits + 1 473 > precision * LITTLENUM_NUMBER_OF_BITS) 474 { 475 /* Exponent overflow. */ 476 make_invalid_floating_point_number (words); 477 return return_value; 478 } 479 #ifdef TC_M68K 480 if (precision == X_PRECISION && exponent_bits == 15) 481 *lp++ = 0; 482 #endif 483 while (num_bits >= LITTLENUM_NUMBER_OF_BITS) 484 { 485 num_bits -= LITTLENUM_NUMBER_OF_BITS; 486 *lp++ = 0; 487 } 488 if (num_bits) 489 *lp++ = next_bits (LITTLENUM_NUMBER_OF_BITS - (num_bits)); 490 } 491 else 492 { 493 if (precision == X_PRECISION && exponent_bits == 15) 494 { 495 *lp++ = word1; 496 #ifdef TC_M68K 497 *lp++ = 0; 498 #endif 499 *lp++ = next_bits (LITTLENUM_NUMBER_OF_BITS - num_bits); 500 } 501 else 502 { 503 word1 |= next_bits ((LITTLENUM_NUMBER_OF_BITS - 1) 504 - (exponent_bits + num_bits)); 505 *lp++ = word1; 506 } 507 } 508 while (lp < words_end) 509 *lp++ = next_bits (LITTLENUM_NUMBER_OF_BITS); 510 511 /* Round the mantissa up, but don't change the number. */ 512 if (next_bits (1)) 513 { 514 --lp; 515 if (prec_bits >= LITTLENUM_NUMBER_OF_BITS) 516 { 517 int n = 0; 518 int tmp_bits; 519 520 n = 0; 521 tmp_bits = prec_bits; 522 while (tmp_bits > LITTLENUM_NUMBER_OF_BITS) 523 { 524 if (lp[n] != (LITTLENUM_TYPE) - 1) 525 break; 526 --n; 527 tmp_bits -= LITTLENUM_NUMBER_OF_BITS; 528 } 529 if (tmp_bits > LITTLENUM_NUMBER_OF_BITS 530 || (lp[n] & mask[tmp_bits]) != mask[tmp_bits] 531 || (prec_bits != (precision * LITTLENUM_NUMBER_OF_BITS 532 - exponent_bits - 1) 533 #ifdef TC_I386 534 /* An extended precision float with only the integer 535 bit set would be invalid. That must be converted 536 to the smallest normalized number. */ 537 && !(precision == X_PRECISION 538 && prec_bits == (precision * LITTLENUM_NUMBER_OF_BITS 539 - exponent_bits - 2)) 540 #endif 541 )) 542 { 543 unsigned long carry; 544 545 for (carry = 1; carry && (lp >= words); lp--) 546 { 547 carry = *lp + carry; 548 *lp = carry; 549 carry >>= LITTLENUM_NUMBER_OF_BITS; 550 } 551 } 552 else 553 { 554 /* This is an overflow of the denormal numbers. We 555 need to forget what we have produced, and instead 556 generate the smallest normalized number. */ 557 lp = words; 558 word1 = ((generic_floating_point_number.sign == '+') 559 ? 0 560 : (1 << (LITTLENUM_NUMBER_OF_BITS - 1))); 561 word1 |= (1 562 << ((LITTLENUM_NUMBER_OF_BITS - 1) 563 - exponent_bits)); 564 *lp++ = word1; 565 #ifdef TC_I386 566 /* Set the integer bit in the extended precision format. 567 This cannot happen on the m68k where the mantissa 568 just overflows into the integer bit above. */ 569 if (precision == X_PRECISION) 570 *lp++ = 1 << (LITTLENUM_NUMBER_OF_BITS - 1); 571 #endif 572 while (lp < words_end) 573 *lp++ = 0; 574 } 575 } 576 else 577 *lp += 1; 578 } 579 580 return return_value; 581 } 582 else if ((unsigned long) exponent_4 > mask[exponent_bits] 583 || (! TC_LARGEST_EXPONENT_IS_NORMAL (precision) 584 && (unsigned long) exponent_4 == mask[exponent_bits])) 585 { 586 /* Exponent overflow. Lose immediately. */ 587 588 /* We leave return_value alone: admit we read the 589 number, but return a floating exception 590 because we can't encode the number. */ 591 make_invalid_floating_point_number (words); 592 return return_value; 593 } 594 else 595 { 596 word1 |= (exponent_4 << ((LITTLENUM_NUMBER_OF_BITS - 1) - exponent_bits)) 597 | next_bits ((LITTLENUM_NUMBER_OF_BITS - 1) - exponent_bits); 598 } 599 600 *lp++ = word1; 601 602 /* X_PRECISION is special: on the 68k, it has 16 bits of zero in the 603 middle. Either way, it is then followed by a 1 bit. */ 604 if (exponent_bits == 15 && precision == X_PRECISION) 605 { 606 #ifdef TC_M68K 607 *lp++ = 0; 608 #endif 609 *lp++ = (1 << (LITTLENUM_NUMBER_OF_BITS - 1) 610 | next_bits (LITTLENUM_NUMBER_OF_BITS - 1)); 611 } 612 613 /* The rest of the words are just mantissa bits. */ 614 while (lp < words_end) 615 *lp++ = next_bits (LITTLENUM_NUMBER_OF_BITS); 616 617 if (next_bits (1)) 618 { 619 unsigned long carry; 620 /* Since the NEXT bit is a 1, round UP the mantissa. 621 The cunning design of these hidden-1 floats permits 622 us to let the mantissa overflow into the exponent, and 623 it 'does the right thing'. However, we lose if the 624 highest-order bit of the lowest-order word flips. 625 Is that clear? */ 626 627 /* #if (sizeof(carry)) < ((sizeof(bits[0]) * BITS_PER_CHAR) + 2) 628 Please allow at least 1 more bit in carry than is in a LITTLENUM. 629 We need that extra bit to hold a carry during a LITTLENUM carry 630 propagation. Another extra bit (kept 0) will assure us that we 631 don't get a sticky sign bit after shifting right, and that 632 permits us to propagate the carry without any masking of bits. 633 #endif */ 634 for (carry = 1, lp--; carry; lp--) 635 { 636 carry = *lp + carry; 637 *lp = carry; 638 carry >>= LITTLENUM_NUMBER_OF_BITS; 639 if (lp == words) 640 break; 641 } 642 if (precision == X_PRECISION && exponent_bits == 15) 643 { 644 /* Extended precision numbers have an explicit integer bit 645 that we may have to restore. */ 646 if (lp == words) 647 { 648 #ifdef TC_M68K 649 /* On the m68k there is a gap of 16 bits. We must 650 explicitly propagate the carry into the exponent. */ 651 words[0] += words[1]; 652 words[1] = 0; 653 lp++; 654 #endif 655 /* Put back the integer bit. */ 656 lp[1] |= 1 << (LITTLENUM_NUMBER_OF_BITS - 1); 657 } 658 } 659 if ((word1 ^ *words) & (1 << (LITTLENUM_NUMBER_OF_BITS - 1))) 660 { 661 /* We leave return_value alone: admit we read the number, 662 but return a floating exception because we can't encode 663 the number. */ 664 *words &= ~(1 << (LITTLENUM_NUMBER_OF_BITS - 1)); 665 } 666 } 667 return return_value; 668 } 669 670 #ifdef TEST 671 char * 672 print_gen (gen) 673 FLONUM_TYPE *gen; 674 { 675 FLONUM_TYPE f; 676 LITTLENUM_TYPE arr[10]; 677 double dv; 678 float fv; 679 static char sbuf[40]; 680 681 if (gen) 682 { 683 f = generic_floating_point_number; 684 generic_floating_point_number = *gen; 685 } 686 gen_to_words (&arr[0], 4, 11); 687 memcpy (&dv, &arr[0], sizeof (double)); 688 sprintf (sbuf, "%x %x %x %x %.14G ", arr[0], arr[1], arr[2], arr[3], dv); 689 gen_to_words (&arr[0], 2, 8); 690 memcpy (&fv, &arr[0], sizeof (float)); 691 sprintf (sbuf + strlen (sbuf), "%x %x %.12g\n", arr[0], arr[1], fv); 692 693 if (gen) 694 generic_floating_point_number = f; 695 696 return (sbuf); 697 } 698 #endif 699 700 #define MAX_LITTLENUMS 6 701 702 /* This is a utility function called from various tc-*.c files. It 703 is here in order to reduce code duplication. 704 705 Turn a string at input_line_pointer into a floating point constant 706 of type TYPE (a character found in the FLT_CHARS macro), and store 707 it as LITTLENUMS in the bytes buffer LITP. The number of chars 708 emitted is stored in *SIZEP. BIG_WORDIAN is TRUE if the littlenums 709 should be emitted most significant littlenum first. 710 711 An error message is returned, or a NULL pointer if everything went OK. */ 712 713 const char * 714 ieee_md_atof (int type, 715 char *litP, 716 int *sizeP, 717 bfd_boolean big_wordian) 718 { 719 LITTLENUM_TYPE words[MAX_LITTLENUMS]; 720 LITTLENUM_TYPE *wordP; 721 char *t; 722 int prec = 0; 723 724 if (strchr (FLT_CHARS, type) != NULL) 725 { 726 switch (type) 727 { 728 case 'f': 729 case 'F': 730 case 's': 731 case 'S': 732 prec = F_PRECISION; 733 break; 734 735 case 'd': 736 case 'D': 737 case 'r': 738 case 'R': 739 prec = D_PRECISION; 740 break; 741 742 case 't': 743 case 'T': 744 prec = X_PRECISION; 745 type = 'x'; /* This is what atof_ieee() understands. */ 746 break; 747 748 case 'x': 749 case 'X': 750 case 'p': 751 case 'P': 752 #ifdef TC_M68K 753 /* Note: on the m68k there is a gap of 16 bits (one littlenum) 754 between the exponent and mantissa. Hence the precision is 755 6 and not 5. */ 756 prec = P_PRECISION + 1; 757 #else 758 prec = P_PRECISION; 759 #endif 760 break; 761 762 default: 763 break; 764 } 765 } 766 /* The 'f' and 'd' types are always recognised, even if the target has 767 not put them into the FLT_CHARS macro. This is because the 'f' type 768 can come from the .dc.s, .dcb.s, .float or .single pseudo-ops and the 769 'd' type from the .dc.d, .dbc.d or .double pseudo-ops. 770 771 The 'x' type is not implicitly recongised however, even though it can 772 be generated by the .dc.x and .dbc.x pseudo-ops because not all targets 773 can support floating point values that big. ie the target has to 774 explicitly allow them by putting them into FLT_CHARS. */ 775 else if (type == 'f') 776 prec = F_PRECISION; 777 else if (type == 'd') 778 prec = D_PRECISION; 779 780 if (prec == 0) 781 { 782 *sizeP = 0; 783 return _("Unrecognized or unsupported floating point constant"); 784 } 785 786 gas_assert (prec <= MAX_LITTLENUMS); 787 788 t = atof_ieee (input_line_pointer, type, words); 789 if (t) 790 input_line_pointer = t; 791 792 *sizeP = prec * sizeof (LITTLENUM_TYPE); 793 794 if (big_wordian) 795 { 796 for (wordP = words; prec --;) 797 { 798 md_number_to_chars (litP, (valueT) (* wordP ++), sizeof (LITTLENUM_TYPE)); 799 litP += sizeof (LITTLENUM_TYPE); 800 } 801 } 802 else 803 { 804 for (wordP = words + prec; prec --;) 805 { 806 md_number_to_chars (litP, (valueT) (* -- wordP), sizeof (LITTLENUM_TYPE)); 807 litP += sizeof (LITTLENUM_TYPE); 808 } 809 } 810 811 return NULL; 812 } 813
