added mpfr_set_decimal128 (work in progress, not yet fully tested)

git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@12766 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 490 insertions, 0 deletions

diff --git a/src/set_d128.c b/src/set_d128.c
new file mode 100644
index 000000000..3e1bda142
--- /dev/null
+++ b/src/set_d128.c
@@ -0,0 +1,490 @@
+/* mpfr_set_decimal128 -- convert a IEEE 754r decimal128 float to
+                          a multiple precision floating-point number
+
+See https://gcc.gnu.org/ml/gcc/2006-06/msg00691.html,
+https://gcc.gnu.org/onlinedocs/gcc/Decimal-Float.html,
+and TR 24732 <http://www.open-std.org/jtc1/sc22/wg14/www/projects#24732>.
+
+Copyright 2006-2016 Free Software Foundation, Inc.
+Contributed by the AriC and Caramel projects, INRIA.
+
+This file is part of the GNU MPFR Library.
+
+The GNU MPFR Library is free software; you can redistribute it and/or modify
+it under the terms of the GNU Lesser General Public License as published by
+the Free Software Foundation; either version 3 of the License, or (at your
+option) any later version.
+
+The GNU MPFR Library is distributed in the hope that it will be useful, but
+WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
+License for more details.
+
+You should have received a copy of the GNU Lesser General Public License
+along with the GNU MPFR Library; see the file COPYING.LESSER.  If not, see
+http://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
+51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
+
+#define MPFR_NEED_LONGLONG_H
+#include "mpfr-impl.h"
+
+#ifdef MPFR_WANT_DECIMAL_FLOATS
+#ifdef DPD_FORMAT
+  /* conversion 10-bits to 3 digits */
+static unsigned int T[1024] = {
+  0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 80, 81, 800, 801, 880, 881, 10, 11, 12, 13,
+  14, 15, 16, 17, 18, 19, 90, 91, 810, 811, 890, 891, 20, 21, 22, 23, 24, 25,
+  26, 27, 28, 29, 82, 83, 820, 821, 808, 809, 30, 31, 32, 33, 34, 35, 36, 37,
+  38, 39, 92, 93, 830, 831, 818, 819, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49,
+  84, 85, 840, 841, 88, 89, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 94, 95,
+  850, 851, 98, 99, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 86, 87, 860, 861,
+  888, 889, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 96, 97, 870, 871, 898,
+  899, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 180, 181, 900, 901,
+  980, 981, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 190, 191, 910,
+  911, 990, 991, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 182, 183,
+  920, 921, 908, 909, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 192,
+  193, 930, 931, 918, 919, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149,
+  184, 185, 940, 941, 188, 189, 150, 151, 152, 153, 154, 155, 156, 157, 158,
+  159, 194, 195, 950, 951, 198, 199, 160, 161, 162, 163, 164, 165, 166, 167,
+  168, 169, 186, 187, 960, 961, 988, 989, 170, 171, 172, 173, 174, 175, 176,
+  177, 178, 179, 196, 197, 970, 971, 998, 999, 200, 201, 202, 203, 204, 205,
+  206, 207, 208, 209, 280, 281, 802, 803, 882, 883, 210, 211, 212, 213, 214,
+  215, 216, 217, 218, 219, 290, 291, 812, 813, 892, 893, 220, 221, 222, 223,
+  224, 225, 226, 227, 228, 229, 282, 283, 822, 823, 828, 829, 230, 231, 232,
+  233, 234, 235, 236, 237, 238, 239, 292, 293, 832, 833, 838, 839, 240, 241,
+  242, 243, 244, 245, 246, 247, 248, 249, 284, 285, 842, 843, 288, 289, 250,
+  251, 252, 253, 254, 255, 256, 257, 258, 259, 294, 295, 852, 853, 298, 299,
+  260, 261, 262, 263, 264, 265, 266, 267, 268, 269, 286, 287, 862, 863, 888,
+  889, 270, 271, 272, 273, 274, 275, 276, 277, 278, 279, 296, 297, 872, 873,
+  898, 899, 300, 301, 302, 303, 304, 305, 306, 307, 308, 309, 380, 381, 902,
+  903, 982, 983, 310, 311, 312, 313, 314, 315, 316, 317, 318, 319, 390, 391,
+  912, 913, 992, 993, 320, 321, 322, 323, 324, 325, 326, 327, 328, 329, 382,
+  383, 922, 923, 928, 929, 330, 331, 332, 333, 334, 335, 336, 337, 338, 339,
+  392, 393, 932, 933, 938, 939, 340, 341, 342, 343, 344, 345, 346, 347, 348,
+  349, 384, 385, 942, 943, 388, 389, 350, 351, 352, 353, 354, 355, 356, 357,
+  358, 359, 394, 395, 952, 953, 398, 399, 360, 361, 362, 363, 364, 365, 366,
+  367, 368, 369, 386, 387, 962, 963, 988, 989, 370, 371, 372, 373, 374, 375,
+  376, 377, 378, 379, 396, 397, 972, 973, 998, 999, 400, 401, 402, 403, 404,
+  405, 406, 407, 408, 409, 480, 481, 804, 805, 884, 885, 410, 411, 412, 413,
+  414, 415, 416, 417, 418, 419, 490, 491, 814, 815, 894, 895, 420, 421, 422,
+  423, 424, 425, 426, 427, 428, 429, 482, 483, 824, 825, 848, 849, 430, 431,
+  432, 433, 434, 435, 436, 437, 438, 439, 492, 493, 834, 835, 858, 859, 440,
+  441, 442, 443, 444, 445, 446, 447, 448, 449, 484, 485, 844, 845, 488, 489,
+  450, 451, 452, 453, 454, 455, 456, 457, 458, 459, 494, 495, 854, 855, 498,
+  499, 460, 461, 462, 463, 464, 465, 466, 467, 468, 469, 486, 487, 864, 865,
+  888, 889, 470, 471, 472, 473, 474, 475, 476, 477, 478, 479, 496, 497, 874,
+  875, 898, 899, 500, 501, 502, 503, 504, 505, 506, 507, 508, 509, 580, 581,
+  904, 905, 984, 985, 510, 511, 512, 513, 514, 515, 516, 517, 518, 519, 590,
+  591, 914, 915, 994, 995, 520, 521, 522, 523, 524, 525, 526, 527, 528, 529,
+  582, 583, 924, 925, 948, 949, 530, 531, 532, 533, 534, 535, 536, 537, 538,
+  539, 592, 593, 934, 935, 958, 959, 540, 541, 542, 543, 544, 545, 546, 547,
+  548, 549, 584, 585, 944, 945, 588, 589, 550, 551, 552, 553, 554, 555, 556,
+  557, 558, 559, 594, 595, 954, 955, 598, 599, 560, 561, 562, 563, 564, 565,
+  566, 567, 568, 569, 586, 587, 964, 965, 988, 989, 570, 571, 572, 573, 574,
+  575, 576, 577, 578, 579, 596, 597, 974, 975, 998, 999, 600, 601, 602, 603,
+  604, 605, 606, 607, 608, 609, 680, 681, 806, 807, 886, 887, 610, 611, 612,
+  613, 614, 615, 616, 617, 618, 619, 690, 691, 816, 817, 896, 897, 620, 621,
+  622, 623, 624, 625, 626, 627, 628, 629, 682, 683, 826, 827, 868, 869, 630,
+  631, 632, 633, 634, 635, 636, 637, 638, 639, 692, 693, 836, 837, 878, 879,
+  640, 641, 642, 643, 644, 645, 646, 647, 648, 649, 684, 685, 846, 847, 688,
+  689, 650, 651, 652, 653, 654, 655, 656, 657, 658, 659, 694, 695, 856, 857,
+  698, 699, 660, 661, 662, 663, 664, 665, 666, 667, 668, 669, 686, 687, 866,
+  867, 888, 889, 670, 671, 672, 673, 674, 675, 676, 677, 678, 679, 696, 697,
+  876, 877, 898, 899, 700, 701, 702, 703, 704, 705, 706, 707, 708, 709, 780,
+  781, 906, 907, 986, 987, 710, 711, 712, 713, 714, 715, 716, 717, 718, 719,
+  790, 791, 916, 917, 996, 997, 720, 721, 722, 723, 724, 725, 726, 727, 728,
+  729, 782, 783, 926, 927, 968, 969, 730, 731, 732, 733, 734, 735, 736, 737,
+  738, 739, 792, 793, 936, 937, 978, 979, 740, 741, 742, 743, 744, 745, 746,
+  747, 748, 749, 784, 785, 946, 947, 788, 789, 750, 751, 752, 753, 754, 755,
+  756, 757, 758, 759, 794, 795, 956, 957, 798, 799, 760, 761, 762, 763, 764,
+  765, 766, 767, 768, 769, 786, 787, 966, 967, 988, 989, 770, 771, 772, 773,
+  774, 775, 776, 777, 778, 779, 796, 797, 976, 977, 998, 999 };
+#endif
+
+#if _GMP_IEEE_FLOATS
+/* Convert d to a decimal string (one-to-one correspondence, no rounding).
+   The string s needs to have at least 44 characters (including the final \0):
+   * 1 for the sign '-'
+   * 2 for the leading '0.'
+   * 34 for the significand
+   * 6 for the exponent (for example 'E-1000')
+   * 1 for the final '\0'
+
+   According to IEEE 754-2008 (page 11), we have k=128, thus w = k/16+4 = 12,
+   t = 15*k/16-10 = 110, p = 9*k/32-2 = 34, emax = 3*2^(w-1) = 6144,
+   emin = 1-emax = -6143, bias = emax+p-2 = 6176.
+
+   The _Decimal128 encoding is:
+   * 1 bit for the sign
+   * a 17-bit (w+5) combination field G
+   * a 110-bit trailing significand field T
+*/
+static void
+decimal128_to_string (char *s, _Decimal128 d)
+{
+  union ieee_double_extract128 x; /* FIXME */
+  union ieee_double_decimal128 y;
+  char *t;
+  int Gh; /* most 5 significant bits from combination field */
+  int exp; /* exponent */
+  mp_limb_t rp[2];
+  mp_size_t rn = 2;
+  unsigned int i;
+#ifdef DPD_FORMAT
+  unsigned int d0, d1, d2, d3, d4, d5;
+#endif
+
+  /* now convert BID or DPD to string */
+  y.d128 = d;
+  x.d = y.d;
+  Gh = x.s.exp >> 6; /* FIXME: check 6 is correct */
+  if (Gh == 31)
+    {
+      sprintf (s, "NaN");
+      return;
+    }
+  else if (Gh == 30)
+    {
+      if (x.s.sig == 0)
+        sprintf (s, "Inf");
+      else
+        sprintf (s, "-Inf");
+      return;
+    }
+  t = s;
+  if (x.s.sig)
+    *t++ = '-';
+
+#ifdef DPD_FORMAT
+  if (Gh < 24)
+    {
+      exp = (x.s.exp >> 1) & 768;
+      d0 = Gh & 7;
+    }
+  else
+    {
+      exp = (x.s.exp & 384) << 1;
+      d0 = 8 | (Gh & 1);
+    }
+  exp |= (x.s.exp & 63) << 2;
+  exp |= x.s.manh >> 18;
+  d1 = (x.s.manh >> 8) & 1023;
+  d2 = ((x.s.manh << 2) | (x.s.manl >> 30)) & 1023;
+  d3 = (x.s.manl >> 20) & 1023;
+  d4 = (x.s.manl >> 10) & 1023;
+  d5 = x.s.manl & 1023;
+  sprintf (t, "%1u%3u%3u%3u%3u%3u", d0, T[d1], T[d2], T[d3], T[d4], T[d5]);
+  /* Warning: some characters may be blank */
+  for (i = 0; i < 16; i++)
+    if (t[i] == ' ')
+      t[i] = '0';
+  t += 16;
+#else /* BID */
+  if (Gh < 24)
+    {
+      /* the biased exponent E is formed from G[0] to G[9] and the
+         significand from bits G[10] through the end of the decoding */
+      exp = x.s.exp >> 1;
+      /* manh has 20 bits, manl has 32 bits */
+      rp[1] = ((x.s.exp & 1) << 20) | x.s.manh;
+      rp[0] = x.s.manl;
+    }
+  else
+    {
+      /* the biased exponent is formed from G[2] to G[11] */
+      exp = (x.s.exp & 511) << 1;
+      rp[1] = x.s.manh;
+      rp[0] = x.s.manl;
+      exp |= rp[1] >> 19;
+      rp[1] &= 524287; /* 2^19-1: cancel G[11] */
+      rp[1] |= 2097152; /* add 2^21 */
+    }
+#if GMP_NUMB_BITS >= 54
+  rp[0] |= rp[1] << 32;
+  rn = 1;
+#endif
+  while (rn > 0 && rp[rn - 1] == 0)
+    rn --;
+  if (rn == 0)
+    {
+      *t = 0;
+      i = 1;
+    }
+  else
+    {
+      i = mpn_get_str ((unsigned char*)t, 10, rp, rn);
+    }
+  while (i-- > 0)
+    *t++ += '0';
+#endif /* DPD or BID */
+
+  exp -= 398; /* unbiased exponent */
+  sprintf (t, "E%d", exp);
+}
+#else
+/* portable version */
+#ifndef DEC128_MAX
+# define DEC128_MAX 9.999999999999999999999999999999999E6144dl
+#endif
+
+static void
+decimal128_to_string (char *s, _Decimal128 d)
+{
+  int sign = 0, n;
+  int exp = 0;
+
+  if (d != d) /* NaN */
+    {
+      sprintf (s, "NaN"); /* sprintf puts a final '\0' */
+      return;
+    }
+  else if (d > DEC128_MAX) /* +Inf */
+    {
+      sprintf (s, "Inf");
+      return;
+    }
+  else if (d < -DEC128_MAX) /* -Inf */
+    {
+      sprintf (s, "-Inf");
+      return;
+    }
+
+  /* now d is neither NaN nor +Inf nor -Inf */
+
+  if (d < (_Decimal128) 0.0)
+    {
+      sign = 1;
+      d = -d;
+    }
+  else if (d == (_Decimal128) -0.0)
+    { /* Warning: the comparison d == -0.0 returns true for d = 0.0 too,
+         copy code from set_d.c here. We first compare to the +0.0 bitstring,
+         in case +0.0 and -0.0 are represented identically. */
+      double dd = (double) d, poszero = +0.0, negzero = DBL_NEG_ZERO;
+      if (memcmp (&dd, &poszero, sizeof(double)) != 0 &&
+          memcmp (&dd, &negzero, sizeof(double)) == 0)
+        {
+          sign = 1;
+          d = -d;
+        }
+    }
+
+  /* now normalize d in [0.1, 1[ */
+  if (d >= (_Decimal128) 1.0)
+    {
+      _Decimal128 ten16 = (double) 1e16; /* 10^16 is exactly representable
+                                           in binary64 */
+      _Decimal128 ten32 = ten16 * ten16;
+      _Decimal128 ten64 = ten32 * ten32;
+      _Decimal128 ten128 = ten64 * ten64;
+      _Decimal128 ten256 = ten128 * ten128;
+      _Decimal128 ten512 = ten256 * ten256;
+      _Decimal128 ten1024 = ten512 * ten512;
+      _Decimal128 ten2048 = ten1024 * ten1024;
+      _Decimal128 ten4096 = ten2048 * ten2048;
+
+      if (d >= ten4096)
+        {
+          d /= ten4096;
+          exp += 4096;
+        }
+      if (d >= ten2048)
+        {
+          d /= ten2048;
+          exp += 2048;
+        }
+      if (d >= ten1024)
+        {
+          d /= ten1024;
+          exp += 1024;
+        }
+      if (d >= ten512)
+        {
+          d /= ten512;
+          exp += 512;
+        }
+      if (d >= ten256)
+        {
+          d /= ten256;
+          exp += 256;
+        }
+      if (d >= ten128)
+        {
+          d /= ten128;
+          exp += 128;
+        }
+      if (d >= ten64)
+        {
+          d /= ten64;
+          exp += 64;
+        }
+      if (d >= ten32)
+        {
+          d /= ten32;
+          exp += 32;
+        }
+      if (d >= (_Decimal128) 10000000000000000.0)
+        {
+          d /= (_Decimal128) 10000000000000000.0;
+          exp += 16;
+        }
+      if (d >= (_Decimal128) 100000000.0)
+        {
+          d /= (_Decimal128) 100000000.0;
+          exp += 8;
+        }
+      if (d >= (_Decimal128) 10000.0)
+        {
+          d /= (_Decimal128) 10000.0;
+          exp += 4;
+        }
+      if (d >= (_Decimal128) 100.0)
+        {
+          d /= (_Decimal128) 100.0;
+          exp += 2;
+        }
+      if (d >= (_Decimal128) 10.0)
+        {
+          d /= (_Decimal128) 10.0;
+          exp += 1;
+        }
+      if (d >= (_Decimal128) 1.0)
+        {
+          d /= (_Decimal128) 10.0;
+          exp += 1;
+        }
+    }
+  else /* d < 1.0 */
+    {
+      _Decimal128 ten16, ten32, ten64, ten128, ten256, ten512, ten1024,
+        ten2048, ten4096;
+
+      ten16 = (double) 1e16; /* 10^16 is exactly representable in binary64 */
+      ten16 = (_Decimal128) 1.0 / ten16; /* 10^(-16), exact */
+      ten32 = ten16 * ten16;
+      ten64 = ten32 * ten32;
+      ten128 = ten64 * ten64;
+      ten256 = ten128 * ten128;
+      ten512 = ten256 * ten256;
+      ten1024 = ten512 * ten512;
+      ten2048 = ten1024 * ten1024;
+      ten4096 = ten2048 * ten2048;
+
+      if (d < ten4096)
+        {
+          d /= ten4096;
+          exp -= 4096;
+        }
+      if (d < ten2048)
+        {
+          d /= ten2048;
+          exp -= 2048;
+        }
+      if (d < ten1024)
+        {
+          d /= ten1024;
+          exp -= 1024;
+        }
+      if (d < ten512)
+        {
+          d /= ten512;
+          exp -= 512;
+        }
+      if (d < ten256)
+        {
+          d /= ten256;
+          exp -= 256;
+        }
+      if (d < ten128)
+        {
+          d /= ten128;
+          exp -= 128;
+        }
+      if (d < ten64)
+        {
+          d /= ten64;
+          exp -= 64;
+        }
+      if (d < ten32)
+        {
+          d /= ten32;
+          exp -= 32;
+        }
+      /* the double constant 0.0000000000000001 is 2028240960365167/2^104,
+         which should be rounded to 1e-16 in _Decimal128 */
+      if (d < (_Decimal128) 0.0000000000000001)
+        {
+          d *= (_Decimal128) 10000000000000000.0;
+          exp -= 16;
+        }
+      /* the double constant 0.00000001 is 3022314549036573/2^78,
+         which should be rounded to 1e-8 in _Decimal128 */
+      if (d < (_Decimal128) 0.00000001)
+        {
+          d *= (_Decimal128) 100000000.0;
+          exp -= 8;
+        }
+      /* the double constant 0.0001 is 7378697629483821/2^66,
+         which should be rounded to 1e-4 in _Decimal128 */
+      if (d < (_Decimal128) 0.0001)
+        {
+          d *= (_Decimal128) 10000.0;
+          exp -= 4;
+        }
+      /* the double constant 0.01 is 5764607523034235/2^59,
+         which should be rounded to 1e-2 in _Decimal128 */
+      if (d < (_Decimal128) 0.01)
+        {
+          d *= (_Decimal128) 100.0;
+          exp -= 2;
+        }
+      /* the double constant 0.1 is 3602879701896397/2^55,
+         which should be rounded to 1e-1 in _Decimal128 */
+      if (d < (_Decimal128) 0.1)
+        {
+          d *= (_Decimal128) 10.0;
+          exp -= 1;
+        }
+    }
+
+  /* now 0.1 <= d < 1 */
+  if (sign == 1)
+    *s++ = '-';
+  *s++ = '0';
+  *s++ = '.';
+  for (n = 0; n < 34; n++)
+    {
+      double e;
+      int r;
+
+      d *= (_Decimal128) 10.0;
+      e = (double) d;
+      r = (int) e;
+      *s++ = '0' + r;
+      d -= (_Decimal128) r;
+    }
+  MPFR_ASSERTN(d == (_Decimal128) 0.0);
+  if (exp != 0)
+    sprintf (s, "E%d", exp); /* adds a final '\0' */
+  else
+    *s = '\0';
+}
+#endif /* _GMP_IEEE_FLOATS */
+
+/* the IEEE754-2008 decimal128 format has 34 digits, with emax=6144,
+   emin=1-emax=-6143 */
+int
+mpfr_set_decimal128 (mpfr_ptr r, _Decimal128 d, mpfr_rnd_t rnd_mode)
+{
+  char s[44]; /* need 1 character for sign,
+                      2 characters for '0.'
+                     34 characters for significand,
+                      1 character for exponent 'E',
+                      5 characters for exponent (including sign),
+                      1 character for terminating \0. */
+
+  decimal128_to_string (s, d);
+  return mpfr_set_str (r, s, 10, rnd_mode);
+}
+
+#endif /* MPFR_WANT_DECIMAL_FLOATS */