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 = 375 { 376 floatformat_big, 128, 0, 1, 11, 1023, 2047, 12, 52, 377 floatformat_intbit_no, 378 "floatformat_ibm_long_double", 379 floatformat_ibm_long_double_is_valid, 380 &floatformat_ieee_double_big 381 }; 382 383 384 #ifndef min 385 #define min(a, b) ((a) < (b) ? (a) : (b)) 386 #endif 387 388 /* Return 1 if any bits are explicitly set in the mantissa of UFROM, 389 format FMT, 0 otherwise. */ 390 static int 391 mant_bits_set (const struct floatformat *fmt, const unsigned char *ufrom) 392 { 393 unsigned int mant_bits, mant_off; 394 int mant_bits_left; 395 396 mant_off = fmt->man_start; 397 mant_bits_left = fmt->man_len; 398 while (mant_bits_left > 0) 399 { 400 mant_bits = min (mant_bits_left, 32); 401 402 if (get_field (ufrom, fmt->byteorder, fmt->totalsize, 403 mant_off, mant_bits) != 0) 404 return 1; 405 406 mant_off += mant_bits; 407 mant_bits_left -= mant_bits; 408 } 409 return 0; 410 } 411 412 /* Extract a field which starts at START and is LEN bits long. DATA and 413 TOTAL_LEN are the thing we are extracting it from, in byteorder ORDER. */ 414 static unsigned long 415 get_field (const unsigned char *data, enum floatformat_byteorders order, 416 unsigned int total_len, unsigned int start, unsigned int len) 417 { 418 unsigned long result = 0; 419 unsigned int cur_byte; 420 int lo_bit, hi_bit, cur_bitshift = 0; 421 int nextbyte = (order == floatformat_little) ? 1 : -1; 422 423 /* Start is in big-endian bit order! Fix that first. */ 424 start = total_len - (start + len); 425 426 /* Start at the least significant part of the field. */ 427 if (order == floatformat_little) 428 cur_byte = start / FLOATFORMAT_CHAR_BIT; 429 else 430 cur_byte = (total_len - start - 1) / FLOATFORMAT_CHAR_BIT; 431 432 lo_bit = start % FLOATFORMAT_CHAR_BIT; 433 hi_bit = min (lo_bit + len, FLOATFORMAT_CHAR_BIT); 434 435 do 436 { 437 unsigned int shifted = *(data + cur_byte) >> lo_bit; 438 unsigned int bits = hi_bit - lo_bit; 439 unsigned int mask = (1 << bits) - 1; 440 result |= (shifted & mask) << cur_bitshift; 441 len -= bits; 442 cur_bitshift += bits; 443 cur_byte += nextbyte; 444 lo_bit = 0; 445 hi_bit = min (len, FLOATFORMAT_CHAR_BIT); 446 } 447 while (len != 0); 448 449 return result; 450 } 451 452 /* Convert from FMT to a double. 453 FROM is the address of the extended float. 454 Store the double in *TO. */ 455 456 void 457 floatformat_to_double (const struct floatformat *fmt, 458 const void *from, double *to) 459 { 460 const unsigned char *ufrom = (const unsigned char *) from; 461 double dto; 462 long exponent; 463 unsigned long mant; 464 unsigned int mant_bits, mant_off; 465 int mant_bits_left; 466 467 /* Split values are not handled specially, since the top half has 468 the correctly rounded double value (in the only supported case of 469 split values). */ 470 471 exponent = get_field (ufrom, fmt->byteorder, fmt->totalsize, 472 fmt->exp_start, fmt->exp_len); 473 474 /* If the exponent indicates a NaN, we don't have information to 475 decide what to do. So we handle it like IEEE, except that we 476 don't try to preserve the type of NaN. FIXME. */ 477 if ((unsigned long) exponent == fmt->exp_nan) 478 { 479 int nan = mant_bits_set (fmt, ufrom); 480 481 /* On certain systems (such as GNU/Linux), the use of the 482 INFINITY macro below may generate a warning that can not be 483 silenced due to a bug in GCC (PR preprocessor/11931). The 484 preprocessor fails to recognise the __extension__ keyword in 485 conjunction with the GNU/C99 extension for hexadecimal 486 floating point constants and will issue a warning when 487 compiling with -pedantic. */ 488 if (nan) 489 dto = NAN; 490 else 491 dto = INFINITY; 492 493 if (get_field (ufrom, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1)) 494 dto = -dto; 495 496 *to = dto; 497 498 return; 499 } 500 501 mant_bits_left = fmt->man_len; 502 mant_off = fmt->man_start; 503 dto = 0.0; 504 505 /* Build the result algebraically. Might go infinite, underflow, etc; 506 who cares. */ 507 508 /* For denorms use minimum exponent. */ 509 if (exponent == 0) 510 exponent = 1 - fmt->exp_bias; 511 else 512 { 513 exponent -= fmt->exp_bias; 514 515 /* If this format uses a hidden bit, explicitly add it in now. 516 Otherwise, increment the exponent by one to account for the 517 integer bit. */ 518 519 if (fmt->intbit == floatformat_intbit_no) 520 dto = ldexp (1.0, exponent); 521 else 522 exponent++; 523 } 524 525 while (mant_bits_left > 0) 526 { 527 mant_bits = min (mant_bits_left, 32); 528 529 mant = get_field (ufrom, fmt->byteorder, fmt->totalsize, 530 mant_off, mant_bits); 531 532 dto += ldexp ((double) mant, exponent - mant_bits); 533 exponent -= mant_bits; 534 mant_off += mant_bits; 535 mant_bits_left -= mant_bits; 536 } 537 538 /* Negate it if negative. */ 539 if (get_field (ufrom, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1)) 540 dto = -dto; 541 *to = dto; 542 } 543 544 static void put_field (unsigned char *, enum floatformat_byteorders, 545 unsigned int, 546 unsigned int, 547 unsigned int, 548 unsigned long); 549 550 /* Set a field which starts at START and is LEN bits long. DATA and 551 TOTAL_LEN are the thing we are extracting it from, in byteorder ORDER. */ 552 static void 553 put_field (unsigned char *data, enum floatformat_byteorders order, 554 unsigned int total_len, unsigned int start, unsigned int len, 555 unsigned long stuff_to_put) 556 { 557 unsigned int cur_byte; 558 int lo_bit, hi_bit; 559 int nextbyte = (order == floatformat_little) ? 1 : -1; 560 561 /* Start is in big-endian bit order! Fix that first. */ 562 start = total_len - (start + len); 563 564 /* Start at the least significant part of the field. */ 565 if (order == floatformat_little) 566 cur_byte = start / FLOATFORMAT_CHAR_BIT; 567 else 568 cur_byte = (total_len - start - 1) / FLOATFORMAT_CHAR_BIT; 569 570 lo_bit = start % FLOATFORMAT_CHAR_BIT; 571 hi_bit = min (lo_bit + len, FLOATFORMAT_CHAR_BIT); 572 573 do 574 { 575 unsigned char *byte_ptr = data + cur_byte; 576 unsigned int bits = hi_bit - lo_bit; 577 unsigned int mask = ((1 << bits) - 1) << lo_bit; 578 *byte_ptr = (*byte_ptr & ~mask) | ((stuff_to_put << lo_bit) & mask); 579 stuff_to_put >>= bits; 580 len -= bits; 581 cur_byte += nextbyte; 582 lo_bit = 0; 583 hi_bit = min (len, FLOATFORMAT_CHAR_BIT); 584 } 585 while (len != 0); 586 } 587 588 /* The converse: convert the double *FROM to an extended float 589 and store where TO points. Neither FROM nor TO have any alignment 590 restrictions. */ 591 592 void 593 floatformat_from_double (const struct floatformat *fmt, 594 const double *from, void *to) 595 { 596 double dfrom; 597 int exponent; 598 double mant; 599 unsigned int mant_bits, mant_off; 600 int mant_bits_left; 601 unsigned char *uto = (unsigned char *) to; 602 603 dfrom = *from; 604 memset (uto, 0, fmt->totalsize / FLOATFORMAT_CHAR_BIT); 605 606 /* Split values are not handled specially, since a bottom half of 607 zero is correct for any value representable as double (in the 608 only supported case of split values). */ 609 610 /* If negative, set the sign bit. */ 611 if (dfrom < 0) 612 { 613 put_field (uto, fmt->byteorder, fmt->totalsize, fmt->sign_start, 1, 1); 614 dfrom = -dfrom; 615 } 616 617 if (dfrom == 0) 618 { 619 /* 0.0. */ 620 return; 621 } 622 623 if (dfrom != dfrom) 624 { 625 /* NaN. */ 626 put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start, 627 fmt->exp_len, fmt->exp_nan); 628 /* Be sure it's not infinity, but NaN value is irrelevant. */ 629 put_field (uto, fmt->byteorder, fmt->totalsize, fmt->man_start, 630 32, 1); 631 return; 632 } 633 634 if (dfrom + dfrom == dfrom) 635 { 636 /* This can only happen for an infinite value (or zero, which we 637 already handled above). */ 638 put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start, 639 fmt->exp_len, fmt->exp_nan); 640 return; 641 } 642 643 mant = frexp (dfrom, &exponent); 644 if (exponent + fmt->exp_bias - 1 > 0) 645 put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start, 646 fmt->exp_len, exponent + fmt->exp_bias - 1); 647 else 648 { 649 /* Handle a denormalized number. FIXME: What should we do for 650 non-IEEE formats? */ 651 put_field (uto, fmt->byteorder, fmt->totalsize, fmt->exp_start, 652 fmt->exp_len, 0); 653 mant = ldexp (mant, exponent + fmt->exp_bias - 1); 654 } 655 656 mant_bits_left = fmt->man_len; 657 mant_off = fmt->man_start; 658 while (mant_bits_left > 0) 659 { 660 unsigned long mant_long; 661 mant_bits = mant_bits_left < 32 ? mant_bits_left : 32; 662 663 mant *= 4294967296.0; 664 mant_long = (unsigned long)mant; 665 mant -= mant_long; 666 667 /* If the integer bit is implicit, and we are not creating a 668 denormalized number, then we need to discard it. */ 669 if ((unsigned int) mant_bits_left == fmt->man_len 670 && fmt->intbit == floatformat_intbit_no 671 && exponent + fmt->exp_bias - 1 > 0) 672 { 673 mant_long &= 0x7fffffff; 674 mant_bits -= 1; 675 } 676 else if (mant_bits < 32) 677 { 678 /* The bits we want are in the most significant MANT_BITS bits of 679 mant_long. Move them to the least significant. */ 680 mant_long >>= 32 - mant_bits; 681 } 682 683 put_field (uto, fmt->byteorder, fmt->totalsize, 684 mant_off, mant_bits, mant_long); 685 mant_off += mant_bits; 686 mant_bits_left -= mant_bits; 687 } 688 } 689 690 /* Return non-zero iff the data at FROM is a valid number in format FMT. */ 691 692 int 693 floatformat_is_valid (const struct floatformat *fmt, const void *from) 694 { 695 return fmt->is_valid (fmt, from); 696 } 697 698 699 #ifdef IEEE_DEBUG 700 701 #include <stdio.h> 702 703 /* This is to be run on a host which uses IEEE floating point. */ 704 705 void 706 ieee_test (double n) 707 { 708 double result; 709 710 floatformat_to_double (&floatformat_ieee_double_little, &n, &result); 711 if ((n != result && (! isnan (n) || ! isnan (result))) 712 || (n < 0 && result >= 0) 713 || (n >= 0 && result < 0)) 714 printf ("Differ(to): %.20g -> %.20g\n", n, result); 715 716 floatformat_from_double (&floatformat_ieee_double_little, &n, &result); 717 if ((n != result && (! isnan (n) || ! isnan (result))) 718 || (n < 0 && result >= 0) 719 || (n >= 0 && result < 0)) 720 printf ("Differ(from): %.20g -> %.20g\n", n, result); 721 722 #if 0 723 { 724 char exten[16]; 725 726 floatformat_from_double (&floatformat_m68881_ext, &n, exten); 727 floatformat_to_double (&floatformat_m68881_ext, exten, &result); 728 if (n != result) 729 printf ("Differ(to+from): %.20g -> %.20g\n", n, result); 730 } 731 #endif 732 733 #if IEEE_DEBUG > 1 734 /* This is to be run on a host which uses 68881 format. */ 735 { 736 long double ex = *(long double *)exten; 737 if (ex != n) 738 printf ("Differ(from vs. extended): %.20g\n", n); 739 } 740 #endif 741 } 742 743 int 744 main (void) 745 { 746 ieee_test (0.0); 747 ieee_test (0.5); 748 ieee_test (1.1); 749 ieee_test (256.0); 750 ieee_test (0.12345); 751 ieee_test (234235.78907234); 752 ieee_test (-512.0); 753 ieee_test (-0.004321); 754 ieee_test (1.2E-70); 755 ieee_test (1.2E-316); 756 ieee_test (4.9406564584124654E-324); 757 ieee_test (- 4.9406564584124654E-324); 758 ieee_test (- 0.0); 759 ieee_test (- INFINITY); 760 ieee_test (- NAN); 761 ieee_test (INFINITY); 762 ieee_test (NAN); 763 return 0; 764 } 765 #endif 766