gcc/dfp.c

   1 /* Decimal floating point support.
   2    Copyright (C) 2005-2020 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify it under
   7 the terms of the GNU General Public License as published by the Free
   8 Software Foundation; either version 3, or (at your option) any later
   9 version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING3.  If not see
  18 <http://www.gnu.org/licenses/>.  */
  19
  20 #include "config.h"
  21 #include "system.h"
  22 #include "coretypes.h"
  23 #include "tm.h"
  24 #include "tree.h"
  25 #include "dfp.h"
  26
  27 /* The order of the following headers is important for making sure
  28    decNumber structure is large enough to hold decimal128 digits.  */
  29
  30 #include "decimal128.h"
  31 #include "decimal64.h"
  32 #include "decimal32.h"
  33
  34 #ifndef WORDS_BIGENDIAN
  35 #define WORDS_BIGENDIAN 0
  36 #endif
  37
  38 /* Initialize R (a real with the decimal flag set) from DN.  Can
  39    utilize status passed in via CONTEXT, if a previous operation had
  40    interesting status.  */
  41
  42 static void
  43 decimal_from_decnumber (REAL_VALUE_TYPE *r, decNumber *dn, decContext *context)
  44 {
  45   memset (r, 0, sizeof (REAL_VALUE_TYPE));
  46
  47   r->cl = rvc_normal;
  48   if (decNumberIsNaN (dn))
  49     r->cl = rvc_nan;
  50   if (decNumberIsInfinite (dn))
  51     r->cl = rvc_inf;
  52   if (context->status & DEC_Overflow)
  53     r->cl = rvc_inf;
  54   if (decNumberIsNegative (dn))
  55     r->sign = 1;
  56   r->decimal = 1;
  57
  58   if (r->cl != rvc_normal)
  59     return;
  60
  61   decContextDefault (context, DEC_INIT_DECIMAL128);
  62   context->traps = 0;
  63
  64   decimal128FromNumber ((decimal128 *) r->sig, dn, context);
  65 }
  66
  67 /* Create decimal encoded R from string S.  */
  68
  69 void
  70 decimal_real_from_string (REAL_VALUE_TYPE *r, const char *s)
  71 {
  72   decNumber dn;
  73   decContext set;
  74   decContextDefault (&set, DEC_INIT_DECIMAL128);
  75   set.traps = 0;
  76
  77   decNumberFromString (&dn, s, &set);
  78
  79   /* It would be more efficient to store directly in decNumber format,
  80      but that is impractical from current data structure size.
  81      Encoding as a decimal128 is much more compact.  */
  82   decimal_from_decnumber (r, &dn, &set);
  83 }
  84
  85 /* Initialize a decNumber from a REAL_VALUE_TYPE.  */
  86
  87 static void
  88 decimal_to_decnumber (const REAL_VALUE_TYPE *r, decNumber *dn)
  89 {
  90   decContext set;
  91   decContextDefault (&set, DEC_INIT_DECIMAL128);
  92   set.traps = 0;
  93
  94   switch (r->cl)
  95     {
  96     case rvc_zero:
  97       decNumberZero (dn);
  98       break;
  99     case rvc_inf:
 100       decNumberFromString (dn, "Infinity", &set);
 101       break;
 102     case rvc_nan:
 103       if (r->signalling)
 104         decNumberFromString (dn, "snan", &set);
 105       else
 106         decNumberFromString (dn, "nan", &set);
 107       break;
 108     case rvc_normal:
 109       if (!r->decimal)
 110         {
 111           /* dconst{1,2,m1,half} are used in various places in
 112              the middle-end and optimizers, allow them here
 113              as an exception by converting them to decimal.  */
 114           if (memcmp (r, &dconst1, sizeof (*r)) == 0)
 115             {
 116               decNumberFromString (dn, "1", &set);
 117               break;
 118             }
 119           if (memcmp (r, &dconst2, sizeof (*r)) == 0)
 120             {
 121               decNumberFromString (dn, "2", &set);
 122               break;
 123             }
 124           if (memcmp (r, &dconstm1, sizeof (*r)) == 0)
 125             {
 126               decNumberFromString (dn, "-1", &set);
 127               break;
 128             }
 129           if (memcmp (r, &dconsthalf, sizeof (*r)) == 0)
 130             {
 131               decNumberFromString (dn, "0.5", &set);
 132               break;
 133             }
 134           gcc_unreachable ();
 135         }
 136       decimal128ToNumber ((const decimal128 *) r->sig, dn);
 137       break;
 138     default:
 139       gcc_unreachable ();
 140     }
 141
 142   /* Fix up sign bit.  */
 143   if (r->sign != decNumberIsNegative (dn))
 144     dn->bits ^= DECNEG;
 145 }
 146
 147 /* Encode a real into an IEEE 754 decimal32 type.  */
 148
 149 void
 150 encode_decimal32 (const struct real_format *fmt ATTRIBUTE_UNUSED,
 151                   long *buf, const REAL_VALUE_TYPE *r)
 152 {
 153   decNumber dn;
 154   decimal32 d32;
 155   decContext set;
 156   int32_t image;
 157
 158   decContextDefault (&set, DEC_INIT_DECIMAL128);
 159   set.traps = 0;
 160
 161   decimal_to_decnumber (r, &dn);
 162   decimal32FromNumber (&d32, &dn, &set);
 163
 164   memcpy (&image, d32.bytes, sizeof (int32_t));
 165   buf[0] = image;
 166 }
 167
 168 /* Decode an IEEE 754 decimal32 type into a real.  */
 169
 170 void
 171 decode_decimal32 (const struct real_format *fmt ATTRIBUTE_UNUSED,
 172                   REAL_VALUE_TYPE *r, const long *buf)
 173 {
 174   decNumber dn;
 175   decimal32 d32;
 176   decContext set;
 177   int32_t image;
 178
 179   decContextDefault (&set, DEC_INIT_DECIMAL128);
 180   set.traps = 0;
 181
 182   image = buf[0];
 183   memcpy (&d32.bytes, &image, sizeof (int32_t));
 184
 185   decimal32ToNumber (&d32, &dn);
 186   decimal_from_decnumber (r, &dn, &set);
 187 }
 188
 189 /* Encode a real into an IEEE 754 decimal64 type.  */
 190
 191 void
 192 encode_decimal64 (const struct real_format *fmt ATTRIBUTE_UNUSED,
 193                   long *buf, const REAL_VALUE_TYPE *r)
 194 {
 195   decNumber dn;
 196   decimal64 d64;
 197   decContext set;
 198   int32_t image;
 199
 200   decContextDefault (&set, DEC_INIT_DECIMAL128);
 201   set.traps = 0;
 202
 203   decimal_to_decnumber (r, &dn);
 204   decimal64FromNumber (&d64, &dn, &set);
 205
 206   if (WORDS_BIGENDIAN == FLOAT_WORDS_BIG_ENDIAN)
 207     {
 208       memcpy (&image, &d64.bytes[0], sizeof (int32_t));
 209       buf[0] = image;
 210       memcpy (&image, &d64.bytes[4], sizeof (int32_t));
 211       buf[1] = image;
 212     }
 213   else
 214     {
 215       memcpy (&image, &d64.bytes[4], sizeof (int32_t));
 216       buf[0] = image;
 217       memcpy (&image, &d64.bytes[0], sizeof (int32_t));
 218       buf[1] = image;
 219     }
 220 }
 221
 222 /* Decode an IEEE 754 decimal64 type into a real.  */
 223
 224 void
 225 decode_decimal64 (const struct real_format *fmt ATTRIBUTE_UNUSED,
 226                   REAL_VALUE_TYPE *r, const long *buf)
 227 {
 228   decNumber dn;
 229   decimal64 d64;
 230   decContext set;
 231   int32_t image;
 232
 233   decContextDefault (&set, DEC_INIT_DECIMAL128);
 234   set.traps = 0;
 235
 236   if (WORDS_BIGENDIAN == FLOAT_WORDS_BIG_ENDIAN)
 237     {
 238       image = buf[0];
 239       memcpy (&d64.bytes[0], &image, sizeof (int32_t));
 240       image = buf[1];
 241       memcpy (&d64.bytes[4], &image, sizeof (int32_t));
 242     }
 243   else
 244     {
 245       image = buf[1];
 246       memcpy (&d64.bytes[0], &image, sizeof (int32_t));
 247       image = buf[0];
 248       memcpy (&d64.bytes[4], &image, sizeof (int32_t));
 249     }
 250
 251   decimal64ToNumber (&d64, &dn);
 252   decimal_from_decnumber (r, &dn, &set);
 253 }
 254
 255 /* Encode a real into an IEEE 754 decimal128 type.  */
 256
 257 void
 258 encode_decimal128 (const struct real_format *fmt ATTRIBUTE_UNUSED,
 259                    long *buf, const REAL_VALUE_TYPE *r)
 260 {
 261   decNumber dn;
 262   decContext set;
 263   decimal128 d128;
 264   int32_t image;
 265
 266   decContextDefault (&set, DEC_INIT_DECIMAL128);
 267   set.traps = 0;
 268
 269   decimal_to_decnumber (r, &dn);
 270   decimal128FromNumber (&d128, &dn, &set);
 271
 272   if (WORDS_BIGENDIAN == FLOAT_WORDS_BIG_ENDIAN)
 273     {
 274       memcpy (&image, &d128.bytes[0], sizeof (int32_t));
 275       buf[0] = image;
 276       memcpy (&image, &d128.bytes[4], sizeof (int32_t));
 277       buf[1] = image;
 278       memcpy (&image, &d128.bytes[8], sizeof (int32_t));
 279       buf[2] = image;
 280       memcpy (&image, &d128.bytes[12], sizeof (int32_t));
 281       buf[3] = image;
 282     }
 283   else
 284     {
 285       memcpy (&image, &d128.bytes[12], sizeof (int32_t));
 286       buf[0] = image;
 287       memcpy (&image, &d128.bytes[8], sizeof (int32_t));
 288       buf[1] = image;
 289       memcpy (&image, &d128.bytes[4], sizeof (int32_t));
 290       buf[2] = image;
 291       memcpy (&image, &d128.bytes[0], sizeof (int32_t));
 292       buf[3] = image;
 293     }
 294 }
 295
 296 /* Decode an IEEE 754 decimal128 type into a real.  */
 297
 298 void
 299 decode_decimal128 (const struct real_format *fmt ATTRIBUTE_UNUSED,
 300                    REAL_VALUE_TYPE *r, const long *buf)
 301 {
 302   decNumber dn;
 303   decimal128 d128;
 304   decContext set;
 305   int32_t image;
 306
 307   decContextDefault (&set, DEC_INIT_DECIMAL128);
 308   set.traps = 0;
 309
 310   if (WORDS_BIGENDIAN == FLOAT_WORDS_BIG_ENDIAN)
 311     {
 312       image = buf[0];
 313       memcpy (&d128.bytes[0],  &image, sizeof (int32_t));
 314       image = buf[1];
 315       memcpy (&d128.bytes[4],  &image, sizeof (int32_t));
 316       image = buf[2];
 317       memcpy (&d128.bytes[8],  &image, sizeof (int32_t));
 318       image = buf[3];
 319       memcpy (&d128.bytes[12], &image, sizeof (int32_t));
 320     }
 321   else
 322     {
 323       image = buf[3];
 324       memcpy (&d128.bytes[0],  &image, sizeof (int32_t));
 325       image = buf[2];
 326       memcpy (&d128.bytes[4],  &image, sizeof (int32_t));
 327       image = buf[1];
 328       memcpy (&d128.bytes[8],  &image, sizeof (int32_t));
 329       image = buf[0];
 330       memcpy (&d128.bytes[12], &image, sizeof (int32_t));
 331     }
 332
 333   decimal128ToNumber (&d128, &dn);
 334   decimal_from_decnumber (r, &dn, &set);
 335 }
 336
 337 /* Helper function to convert from a binary real internal
 338    representation.  */
 339
 340 static void
 341 decimal_to_binary (REAL_VALUE_TYPE *to, const REAL_VALUE_TYPE *from,
 342                    const real_format *fmt)
 343 {
 344   char string[256];
 345   const decimal128 *const d128 = (const decimal128 *) from->sig;
 346
 347   decimal128ToString (d128, string);
 348   real_from_string3 (to, string, fmt);
 349 }
 350
 351
 352 /* Helper function to convert from a binary real internal
 353    representation.  */
 354
 355 static void
 356 decimal_from_binary (REAL_VALUE_TYPE *to, const REAL_VALUE_TYPE *from)
 357 {
 358   char string[256];
 359
 360   /* We convert to string, then to decNumber then to decimal128.  */
 361   real_to_decimal (string, from, sizeof (string), 0, 1);
 362   decimal_real_from_string (to, string);
 363 }
 364
 365 /* Helper function to real.c:do_compare() to handle decimal internal
 366    representation including when one of the operands is still in the
 367    binary internal representation.  */
 368
 369 int
 370 decimal_do_compare (const REAL_VALUE_TYPE *a, const REAL_VALUE_TYPE *b,
 371                     int nan_result)
 372 {
 373   decContext set;
 374   decNumber dn, dn2, dn3;
 375   REAL_VALUE_TYPE a1, b1;
 376
 377   /* If either operand is non-decimal, create temporary versions.  */
 378   if (!a->decimal)
 379     {
 380       decimal_from_binary (&a1, a);
 381       a = &a1;
 382     }
 383   if (!b->decimal)
 384     {
 385       decimal_from_binary (&b1, b);
 386       b = &b1;
 387     }
 388
 389   /* Convert into decNumber form for comparison operation.  */
 390   decContextDefault (&set, DEC_INIT_DECIMAL128);
 391   set.traps = 0;
 392   decimal128ToNumber ((const decimal128 *) a->sig, &dn2);
 393   decimal128ToNumber ((const decimal128 *) b->sig, &dn3);
 394
 395   /* Finally, do the comparison.  */
 396   decNumberCompare (&dn, &dn2, &dn3, &set);
 397
 398   /* Return the comparison result.  */
 399   if (decNumberIsNaN (&dn))
 400     return nan_result;
 401   else if (decNumberIsZero (&dn))
 402     return 0;
 403   else if (decNumberIsNegative (&dn))
 404     return -1;
 405   else
 406     return 1;
 407 }
 408
 409 /* Helper to round_for_format, handling decimal float types.  */
 410
 411 void
 412 decimal_round_for_format (const struct real_format *fmt, REAL_VALUE_TYPE *r)
 413 {
 414   decNumber dn;
 415   decContext set;
 416
 417   /* Real encoding occurs later.  */
 418   if (r->cl != rvc_normal)
 419     return;
 420
 421   decContextDefault (&set, DEC_INIT_DECIMAL128);
 422   set.traps = 0;
 423   decimal128ToNumber ((decimal128 *) r->sig, &dn);
 424
 425   if (fmt == &decimal_quad_format)
 426     {
 427       /* The internal format is already in this format.  */
 428       return;
 429     }
 430   else if (fmt == &decimal_single_format)
 431     {
 432       decimal32 d32;
 433       decContextDefault (&set, DEC_INIT_DECIMAL32);
 434       set.traps = 0;
 435
 436       decimal32FromNumber (&d32, &dn, &set);
 437       decimal32ToNumber (&d32, &dn);
 438     }
 439   else if (fmt == &decimal_double_format)
 440     {
 441       decimal64 d64;
 442       decContextDefault (&set, DEC_INIT_DECIMAL64);
 443       set.traps = 0;
 444
 445       decimal64FromNumber (&d64, &dn, &set);
 446       decimal64ToNumber (&d64, &dn);
 447     }
 448   else
 449     gcc_unreachable ();
 450
 451   decimal_from_decnumber (r, &dn, &set);
 452 }
 453
 454 /* Extend or truncate to a new mode.  Handles conversions between
 455    binary and decimal types.  */
 456
 457 void
 458 decimal_real_convert (REAL_VALUE_TYPE *r, const real_format *fmt,
 459                       const REAL_VALUE_TYPE *a)
 460 {
 461   if (a->decimal && fmt->b == 10)
 462     return;
 463   if (a->decimal)
 464       decimal_to_binary (r, a, fmt);
 465   else
 466       decimal_from_binary (r, a);
 467 }
 468
 469 /* Render R_ORIG as a decimal floating point constant.  Emit DIGITS
 470    significant digits in the result, bounded by BUF_SIZE.  If DIGITS
 471    is 0, choose the maximum for the representation.  If
 472    CROP_TRAILING_ZEROS, strip trailing zeros.  Currently, not honoring
 473    DIGITS or CROP_TRAILING_ZEROS.  */
 474
 475 void
 476 decimal_real_to_decimal (char *str, const REAL_VALUE_TYPE *r_orig,
 477                          size_t buf_size,
 478                          size_t digits ATTRIBUTE_UNUSED,
 479                          int crop_trailing_zeros ATTRIBUTE_UNUSED)
 480 {
 481   const decimal128 *const d128 = (const decimal128*) r_orig->sig;
 482
 483   /* decimal128ToString requires space for at least 24 characters;
 484      Require two more for suffix.  */
 485   gcc_assert (buf_size >= 24);
 486   decimal128ToString (d128, str);
 487 }
 488
 489 static bool
 490 decimal_do_add (REAL_VALUE_TYPE *r, const REAL_VALUE_TYPE *op0,
 491                 const REAL_VALUE_TYPE *op1, int subtract_p)
 492 {
 493   decNumber dn;
 494   decContext set;
 495   decNumber dn2, dn3;
 496
 497   decimal_to_decnumber (op0, &dn2);
 498   decimal_to_decnumber (op1, &dn3);
 499
 500   decContextDefault (&set, DEC_INIT_DECIMAL128);
 501   set.traps = 0;
 502
 503   if (subtract_p)
 504     decNumberSubtract (&dn, &dn2, &dn3, &set);
 505   else
 506     decNumberAdd (&dn, &dn2, &dn3, &set);
 507
 508   decimal_from_decnumber (r, &dn, &set);
 509
 510   /* Return true, if inexact.  */
 511   return (set.status & DEC_Inexact);
 512 }
 513
 514 /* Compute R = OP0 * OP1.  */
 515
 516 static bool
 517 decimal_do_multiply (REAL_VALUE_TYPE *r, const REAL_VALUE_TYPE *op0,
 518                      const REAL_VALUE_TYPE *op1)
 519 {
 520   decContext set;
 521   decNumber dn, dn2, dn3;
 522
 523   decimal_to_decnumber (op0, &dn2);
 524   decimal_to_decnumber (op1, &dn3);
 525
 526   decContextDefault (&set, DEC_INIT_DECIMAL128);
 527   set.traps = 0;
 528
 529   decNumberMultiply (&dn, &dn2, &dn3, &set);
 530   decimal_from_decnumber (r, &dn, &set);
 531
 532   /* Return true, if inexact.  */
 533   return (set.status & DEC_Inexact);
 534 }
 535
 536 /* Compute R = OP0 / OP1.  */
 537
 538 static bool
 539 decimal_do_divide (REAL_VALUE_TYPE *r, const REAL_VALUE_TYPE *op0,
 540                    const REAL_VALUE_TYPE *op1)
 541 {
 542   decContext set;
 543   decNumber dn, dn2, dn3;
 544
 545   decimal_to_decnumber (op0, &dn2);
 546   decimal_to_decnumber (op1, &dn3);
 547
 548   decContextDefault (&set, DEC_INIT_DECIMAL128);
 549   set.traps = 0;
 550
 551   decNumberDivide (&dn, &dn2, &dn3, &set);
 552   decimal_from_decnumber (r, &dn, &set);
 553
 554   /* Return true, if inexact.  */
 555   return (set.status & DEC_Inexact);
 556 }
 557
 558 /* Set R to A truncated to an integral value toward zero (decimal
 559    floating point).  */
 560
 561 void
 562 decimal_do_fix_trunc (REAL_VALUE_TYPE *r, const REAL_VALUE_TYPE *a)
 563 {
 564   decNumber dn, dn2;
 565   decContext set;
 566
 567   decContextDefault (&set, DEC_INIT_DECIMAL128);
 568   set.traps = 0;
 569   set.round = DEC_ROUND_DOWN;
 570   decimal128ToNumber ((const decimal128 *) a->sig, &dn2);
 571
 572   decNumberToIntegralValue (&dn, &dn2, &set);
 573   decimal_from_decnumber (r, &dn, &set);
 574 }
 575
 576 /* Render decimal float value R as an integer.  */
 577
 578 HOST_WIDE_INT
 579 decimal_real_to_integer (const REAL_VALUE_TYPE *r)
 580 {
 581   decContext set;
 582   decNumber dn, dn2, dn3;
 583   REAL_VALUE_TYPE to;
 584   char string[256];
 585
 586   decContextDefault (&set, DEC_INIT_DECIMAL128);
 587   set.traps = 0;
 588   set.round = DEC_ROUND_DOWN;
 589   decimal128ToNumber ((const decimal128 *) r->sig, &dn);
 590
 591   decNumberToIntegralValue (&dn2, &dn, &set);
 592   decNumberZero (&dn3);
 593   decNumberRescale (&dn, &dn2, &dn3, &set);
 594
 595   /* Convert to REAL_VALUE_TYPE and call appropriate conversion
 596      function.  */
 597   decNumberToString (&dn, string);
 598   real_from_string (&to, string);
 599   return real_to_integer (&to);
 600 }
 601
 602 /* Likewise, but returns a wide_int with PRECISION.  *FAIL is set if the
 603    value does not fit.  */
 604
 605 wide_int
 606 decimal_real_to_integer (const REAL_VALUE_TYPE *r, bool *fail, int precision)
 607 {
 608   decContext set;
 609   decNumber dn, dn2, dn3;
 610   REAL_VALUE_TYPE to;
 611   char string[256];
 612
 613   decContextDefault (&set, DEC_INIT_DECIMAL128);
 614   set.traps = 0;
 615   set.round = DEC_ROUND_DOWN;
 616   decimal128ToNumber ((const decimal128 *) r->sig, &dn);
 617
 618   decNumberToIntegralValue (&dn2, &dn, &set);
 619   decNumberZero (&dn3);
 620   decNumberRescale (&dn, &dn2, &dn3, &set);
 621
 622   /* Convert to REAL_VALUE_TYPE and call appropriate conversion
 623      function.  */
 624   decNumberToString (&dn, string);
 625   real_from_string (&to, string);
 626   return real_to_integer (&to, fail, precision);
 627 }
 628
 629 /* Perform the decimal floating point operation described by CODE.
 630    For a unary operation, OP1 will be NULL.  This function returns
 631    true if the result may be inexact due to loss of precision.  */
 632
 633 bool
 634 decimal_real_arithmetic (REAL_VALUE_TYPE *r, enum tree_code code,
 635                          const REAL_VALUE_TYPE *op0,
 636                          const REAL_VALUE_TYPE *op1)
 637 {
 638   REAL_VALUE_TYPE a, b;
 639
 640   /* If either operand is non-decimal, create temporaries.  */
 641   if (!op0->decimal)
 642     {
 643       decimal_from_binary (&a, op0);
 644       op0 = &a;
 645     }
 646   if (op1 && !op1->decimal)
 647     {
 648       decimal_from_binary (&b, op1);
 649       op1 = &b;
 650     }
 651
 652   switch (code)
 653     {
 654     case PLUS_EXPR:
 655       return decimal_do_add (r, op0, op1, 0);
 656
 657     case MINUS_EXPR:
 658       return decimal_do_add (r, op0, op1, 1);
 659
 660     case MULT_EXPR:
 661       return decimal_do_multiply (r, op0, op1);
 662
 663     case RDIV_EXPR:
 664       return decimal_do_divide (r, op0, op1);
 665
 666     case MIN_EXPR:
 667       if (op1->cl == rvc_nan)
 668         *r = *op1;
 669       else if (real_compare (UNLT_EXPR, op0, op1))
 670         *r = *op0;
 671       else
 672         *r = *op1;
 673       return false;
 674
 675     case MAX_EXPR:
 676       if (op1->cl == rvc_nan)
 677         *r = *op1;
 678       else if (real_compare (LT_EXPR, op0, op1))
 679         *r = *op1;
 680       else
 681         *r = *op0;
 682       return false;
 683
 684     case NEGATE_EXPR:
 685       {
 686         *r = *op0;
 687         /* Flip sign bit.  */
 688         decimal128FlipSign ((decimal128 *) r->sig);
 689         /* Keep sign field in sync.  */
 690         r->sign ^= 1;
 691       }
 692       return false;
 693
 694     case ABS_EXPR:
 695       {
 696         *r = *op0;
 697         /* Clear sign bit.  */
 698         decimal128ClearSign ((decimal128 *) r->sig);
 699         /* Keep sign field in sync.  */
 700         r->sign = 0;
 701       }
 702       return false;
 703
 704     case FIX_TRUNC_EXPR:
 705       decimal_do_fix_trunc (r, op0);
 706       return false;
 707
 708     default:
 709       gcc_unreachable ();
 710     }
 711 }
 712
 713 /* Fills R with the largest finite value representable in mode MODE.
 714    If SIGN is nonzero, R is set to the most negative finite value.  */
 715
 716 void
 717 decimal_real_maxval (REAL_VALUE_TYPE *r, int sign, machine_mode mode)
 718 {
 719   const char *max;
 720
 721   switch (mode)
 722     {
 723     case E_SDmode:
 724       max = "9.999999E96";
 725       break;
 726     case E_DDmode:
 727       max = "9.999999999999999E384";
 728       break;
 729     case E_TDmode:
 730       max = "9.999999999999999999999999999999999E6144";
 731       break;
 732     default:
 733       gcc_unreachable ();
 734     }
 735
 736   decimal_real_from_string (r, max);
 737   if (sign)
 738     decimal128SetSign ((decimal128 *) r->sig, 1);
 739 }