gcc/double-int.c

   1 /* Operations with long integers.
   2    Copyright (C) 2006, 2007, 2009 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
   7 under the terms of the GNU General Public License as published by the
   8 Free Software Foundation; either version 3, or (at your option) any
   9 later version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT
  12 ANY 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
  26 /* Returns mask for PREC bits.  */
  27
  28 double_int
  29 double_int_mask (unsigned prec)
  30 {
  31   unsigned HOST_WIDE_INT m;
  32   double_int mask;
  33
  34   if (prec > HOST_BITS_PER_WIDE_INT)
  35     {
  36       prec -= HOST_BITS_PER_WIDE_INT;
  37       m = ((unsigned HOST_WIDE_INT) 2 << (prec - 1)) - 1;
  38       mask.high = (HOST_WIDE_INT) m;
  39       mask.low = ALL_ONES;
  40     }
  41   else
  42     {
  43       mask.high = 0;
  44       mask.low = ((unsigned HOST_WIDE_INT) 2 << (prec - 1)) - 1;
  45     }
  46
  47   return mask;
  48 }
  49
  50 /* Clears the bits of CST over the precision PREC.  If UNS is false, the bits
  51    outside of the precision are set to the sign bit (i.e., the PREC-th one),
  52    otherwise they are set to zero.
  53
  54    This corresponds to returning the value represented by PREC lowermost bits
  55    of CST, with the given signedness.  */
  56
  57 double_int
  58 double_int_ext (double_int cst, unsigned prec, bool uns)
  59 {
  60   if (uns)
  61     return double_int_zext (cst, prec);
  62   else
  63     return double_int_sext (cst, prec);
  64 }
  65
  66 /* The same as double_int_ext with UNS = true.  */
  67
  68 double_int
  69 double_int_zext (double_int cst, unsigned prec)
  70 {
  71   double_int mask = double_int_mask (prec);
  72   double_int r;
  73
  74   r.low = cst.low & mask.low;
  75   r.high = cst.high & mask.high;
  76
  77   return r;
  78 }
  79
  80 /* The same as double_int_ext with UNS = false.  */
  81
  82 double_int
  83 double_int_sext (double_int cst, unsigned prec)
  84 {
  85   double_int mask = double_int_mask (prec);
  86   double_int r;
  87   unsigned HOST_WIDE_INT snum;
  88
  89   if (prec <= HOST_BITS_PER_WIDE_INT)
  90     snum = cst.low;
  91   else
  92     {
  93       prec -= HOST_BITS_PER_WIDE_INT;
  94       snum = (unsigned HOST_WIDE_INT) cst.high;
  95     }
  96   if (((snum >> (prec - 1)) & 1) == 1)
  97     {
  98       r.low = cst.low | ~mask.low;
  99       r.high = cst.high | ~mask.high;
 100     }
 101   else
 102     {
 103       r.low = cst.low & mask.low;
 104       r.high = cst.high & mask.high;
 105     }
 106
 107   return r;
 108 }
 109
 110 /* Constructs long integer from tree CST.  The extra bits over the precision of
 111    the number are filled with sign bit if CST is signed, and with zeros if it
 112    is unsigned.  */
 113
 114 double_int
 115 tree_to_double_int (const_tree cst)
 116 {
 117   /* We do not need to call double_int_restrict here to ensure the semantics as
 118      described, as this is the default one for trees.  */
 119   return TREE_INT_CST (cst);
 120 }
 121
 122 /* Returns true if CST fits in unsigned HOST_WIDE_INT.  */
 123
 124 bool
 125 double_int_fits_in_uhwi_p (double_int cst)
 126 {
 127   return cst.high == 0;
 128 }
 129
 130 /* Returns true if CST fits in signed HOST_WIDE_INT.  */
 131
 132 bool
 133 double_int_fits_in_shwi_p (double_int cst)
 134 {
 135   if (cst.high == 0)
 136     return (HOST_WIDE_INT) cst.low >= 0;
 137   else if (cst.high == -1)
 138     return (HOST_WIDE_INT) cst.low < 0;
 139   else
 140     return false;
 141 }
 142
 143 /* Returns true if CST fits in HOST_WIDE_INT if UNS is false, or in
 144    unsigned HOST_WIDE_INT if UNS is true.  */
 145
 146 bool
 147 double_int_fits_in_hwi_p (double_int cst, bool uns)
 148 {
 149   if (uns)
 150     return double_int_fits_in_uhwi_p (cst);
 151   else
 152     return double_int_fits_in_shwi_p (cst);
 153 }
 154
 155 /* Returns value of CST as a signed number.  CST must satisfy
 156    double_int_fits_in_shwi_p.  */
 157
 158 HOST_WIDE_INT
 159 double_int_to_shwi (double_int cst)
 160 {
 161   return (HOST_WIDE_INT) cst.low;
 162 }
 163
 164 /* Returns value of CST as an unsigned number.  CST must satisfy
 165    double_int_fits_in_uhwi_p.  */
 166
 167 unsigned HOST_WIDE_INT
 168 double_int_to_uhwi (double_int cst)
 169 {
 170   return cst.low;
 171 }
 172
 173 /* Returns A * B.  */
 174
 175 double_int
 176 double_int_mul (double_int a, double_int b)
 177 {
 178   double_int ret;
 179   mul_double (a.low, a.high, b.low, b.high, &ret.low, &ret.high);
 180   return ret;
 181 }
 182
 183 /* Returns A + B.  */
 184
 185 double_int
 186 double_int_add (double_int a, double_int b)
 187 {
 188   double_int ret;
 189   add_double (a.low, a.high, b.low, b.high, &ret.low, &ret.high);
 190   return ret;
 191 }
 192
 193 /* Returns -A.  */
 194
 195 double_int
 196 double_int_neg (double_int a)
 197 {
 198   double_int ret;
 199   neg_double (a.low, a.high, &ret.low, &ret.high);
 200   return ret;
 201 }
 202
 203 /* Returns A / B (computed as unsigned depending on UNS, and rounded as
 204    specified by CODE).  CODE is enum tree_code in fact, but double_int.h
 205    must be included before tree.h.  The remainder after the division is
 206    stored to MOD.  */
 207
 208 double_int
 209 double_int_divmod (double_int a, double_int b, bool uns, unsigned code,
 210                    double_int *mod)
 211 {
 212   double_int ret;
 213
 214   div_and_round_double ((enum tree_code) code, uns, a.low, a.high,
 215                         b.low, b.high, &ret.low, &ret.high,
 216                         &mod->low, &mod->high);
 217   return ret;
 218 }
 219
 220 /* The same as double_int_divmod with UNS = false.  */
 221
 222 double_int
 223 double_int_sdivmod (double_int a, double_int b, unsigned code, double_int *mod)
 224 {
 225   return double_int_divmod (a, b, false, code, mod);
 226 }
 227
 228 /* The same as double_int_divmod with UNS = true.  */
 229
 230 double_int
 231 double_int_udivmod (double_int a, double_int b, unsigned code, double_int *mod)
 232 {
 233   return double_int_divmod (a, b, true, code, mod);
 234 }
 235
 236 /* Returns A / B (computed as unsigned depending on UNS, and rounded as
 237    specified by CODE).  CODE is enum tree_code in fact, but double_int.h
 238    must be included before tree.h.  */
 239
 240 double_int
 241 double_int_div (double_int a, double_int b, bool uns, unsigned code)
 242 {
 243   double_int mod;
 244
 245   return double_int_divmod (a, b, uns, code, &mod);
 246 }
 247
 248 /* The same as double_int_div with UNS = false.  */
 249
 250 double_int
 251 double_int_sdiv (double_int a, double_int b, unsigned code)
 252 {
 253   return double_int_div (a, b, false, code);
 254 }
 255
 256 /* The same as double_int_div with UNS = true.  */
 257
 258 double_int
 259 double_int_udiv (double_int a, double_int b, unsigned code)
 260 {
 261   return double_int_div (a, b, true, code);
 262 }
 263
 264 /* Returns A % B (computed as unsigned depending on UNS, and rounded as
 265    specified by CODE).  CODE is enum tree_code in fact, but double_int.h
 266    must be included before tree.h.  */
 267
 268 double_int
 269 double_int_mod (double_int a, double_int b, bool uns, unsigned code)
 270 {
 271   double_int mod;
 272
 273   double_int_divmod (a, b, uns, code, &mod);
 274   return mod;
 275 }
 276
 277 /* The same as double_int_mod with UNS = false.  */
 278
 279 double_int
 280 double_int_smod (double_int a, double_int b, unsigned code)
 281 {
 282   return double_int_mod (a, b, false, code);
 283 }
 284
 285 /* The same as double_int_mod with UNS = true.  */
 286
 287 double_int
 288 double_int_umod (double_int a, double_int b, unsigned code)
 289 {
 290   return double_int_mod (a, b, true, code);
 291 }
 292
 293 /* Constructs tree in type TYPE from with value given by CST.  Signedness of CST
 294    is assumed to be the same as the signedness of TYPE.  */
 295
 296 tree
 297 double_int_to_tree (tree type, double_int cst)
 298 {
 299   cst = double_int_ext (cst, TYPE_PRECISION (type), TYPE_UNSIGNED (type));
 300
 301   return build_int_cst_wide (type, cst.low, cst.high);
 302 }
 303
 304 /* Returns true if CST fits into range of TYPE.  Signedness of CST is assumed
 305    to be the same as the signedness of TYPE.  */
 306
 307 bool
 308 double_int_fits_to_tree_p (const_tree type, double_int cst)
 309 {
 310   double_int ext = double_int_ext (cst,
 311                                    TYPE_PRECISION (type),
 312                                    TYPE_UNSIGNED (type));
 313
 314   return double_int_equal_p (cst, ext);
 315 }
 316
 317 /* Returns true if CST is negative.  Of course, CST is considered to
 318    be signed.  */
 319
 320 bool
 321 double_int_negative_p (double_int cst)
 322 {
 323   return cst.high < 0;
 324 }
 325
 326 /* Returns -1 if A < B, 0 if A == B and 1 if A > B.  Signedness of the
 327    comparison is given by UNS.  */
 328
 329 int
 330 double_int_cmp (double_int a, double_int b, bool uns)
 331 {
 332   if (uns)
 333     return double_int_ucmp (a, b);
 334   else
 335     return double_int_scmp (a, b);
 336 }
 337
 338 /* Compares two unsigned values A and B.  Returns -1 if A < B, 0 if A == B,
 339    and 1 if A > B.  */
 340
 341 int
 342 double_int_ucmp (double_int a, double_int b)
 343 {
 344   if ((unsigned HOST_WIDE_INT) a.high < (unsigned HOST_WIDE_INT) b.high)
 345     return -1;
 346   if ((unsigned HOST_WIDE_INT) a.high > (unsigned HOST_WIDE_INT) b.high)
 347     return 1;
 348   if (a.low < b.low)
 349     return -1;
 350   if (a.low > b.low)
 351     return 1;
 352
 353   return 0;
 354 }
 355
 356 /* Compares two signed values A and B.  Returns -1 if A < B, 0 if A == B,
 357    and 1 if A > B.  */
 358
 359 int
 360 double_int_scmp (double_int a, double_int b)
 361 {
 362   if (a.high < b.high)
 363     return -1;
 364   if (a.high > b.high)
 365     return 1;
 366   if (a.low < b.low)
 367     return -1;
 368   if (a.low > b.low)
 369     return 1;
 370
 371   return 0;
 372 }
 373
 374 /* Splits last digit of *CST (taken as unsigned) in BASE and returns it.  */
 375
 376 static unsigned
 377 double_int_split_digit (double_int *cst, unsigned base)
 378 {
 379   unsigned HOST_WIDE_INT resl, reml;
 380   HOST_WIDE_INT resh, remh;
 381
 382   div_and_round_double (FLOOR_DIV_EXPR, true, cst->low, cst->high, base, 0,
 383                         &resl, &resh, &reml, &remh);
 384   cst->high = resh;
 385   cst->low = resl;
 386
 387   return reml;
 388 }
 389
 390 /* Dumps CST to FILE.  If UNS is true, CST is considered to be unsigned,
 391    otherwise it is signed.  */
 392
 393 void
 394 dump_double_int (FILE *file, double_int cst, bool uns)
 395 {
 396   unsigned digits[100], n;
 397   int i;
 398
 399   if (double_int_zero_p (cst))
 400     {
 401       fprintf (file, "0");
 402       return;
 403     }
 404
 405   if (!uns && double_int_negative_p (cst))
 406     {
 407       fprintf (file, "-");
 408       cst = double_int_neg (cst);
 409     }
 410
 411   for (n = 0; !double_int_zero_p (cst); n++)
 412     digits[n] = double_int_split_digit (&cst, 10);
 413   for (i = n - 1; i >= 0; i--)
 414     fprintf (file, "%u", digits[i]);
 415 }
 416
 417
 418 /* Sets RESULT to VAL, taken unsigned if UNS is true and as signed
 419    otherwise.  */
 420
 421 void
 422 mpz_set_double_int (mpz_t result, double_int val, bool uns)
 423 {
 424   bool negate = false;
 425   unsigned HOST_WIDE_INT vp[2];
 426
 427   if (!uns && double_int_negative_p (val))
 428     {
 429       negate = true;
 430       val = double_int_neg (val);
 431     }
 432
 433   vp[0] = val.low;
 434   vp[1] = (unsigned HOST_WIDE_INT) val.high;
 435   mpz_import (result, 2, -1, sizeof (HOST_WIDE_INT), 0, 0, vp);
 436
 437   if (negate)
 438     mpz_neg (result, result);
 439 }
 440
 441 /* Returns VAL converted to TYPE.  If WRAP is true, then out-of-range
 442    values of VAL will be wrapped; otherwise, they will be set to the
 443    appropriate minimum or maximum TYPE bound.  */
 444
 445 double_int
 446 mpz_get_double_int (const_tree type, mpz_t val, bool wrap)
 447 {
 448   unsigned HOST_WIDE_INT *vp;
 449   size_t count, numb;
 450   double_int res;
 451
 452   if (!wrap)
 453     {
 454       mpz_t min, max;
 455
 456       mpz_init (min);
 457       mpz_init (max);
 458       get_type_static_bounds (type, min, max);
 459
 460       if (mpz_cmp (val, min) < 0)
 461         mpz_set (val, min);
 462       else if (mpz_cmp (val, max) > 0)
 463         mpz_set (val, max);
 464
 465       mpz_clear (min);
 466       mpz_clear (max);
 467     }
 468
 469   /* Determine the number of unsigned HOST_WIDE_INT that are required
 470      for representing the value.  The code to calculate count is
 471      extracted from the GMP manual, section "Integer Import and Export":
 472      http://gmplib.org/manual/Integer-Import-and-Export.html  */
 473   numb = 8*sizeof(HOST_WIDE_INT);
 474   count = (mpz_sizeinbase (val, 2) + numb-1) / numb;
 475   if (count < 2)
 476     count = 2;
 477   vp = (unsigned HOST_WIDE_INT *) alloca (count * sizeof(HOST_WIDE_INT));
 478
 479   vp[0] = 0;
 480   vp[1] = 0;
 481   mpz_export (vp, &count, -1, sizeof (HOST_WIDE_INT), 0, 0, val);
 482
 483   gcc_assert (wrap || count <= 2);
 484
 485   res.low = vp[0];
 486   res.high = (HOST_WIDE_INT) vp[1];
 487
 488   res = double_int_ext (res, TYPE_PRECISION (type), TYPE_UNSIGNED (type));
 489   if (mpz_sgn (val) < 0)
 490     res = double_int_neg (res);
 491
 492   return res;
 493 }