gcc/real.h

   1 /* Definitions of floating-point access for GNU compiler.
   2    Copyright (C) 1989, 1991, 1994, 1996, 1997, 1998, 1999,
   3    2000, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
   4
   5    This file is part of GCC.
   6
   7    GCC is free software; you can redistribute it and/or modify it under
   8    the terms of the GNU General Public License as published by the Free
   9    Software Foundation; either version 2, or (at your option) any later
  10    version.
  11
  12    GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13    WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14    FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15    for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with GCC; see the file COPYING.  If not, write to the Free
  19    Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
  20    02110-1301, USA.  */
  21
  22 #ifndef GCC_REAL_H
  23 #define GCC_REAL_H
  24
  25 #include <gmp.h>
  26 #include <mpfr.h>
  27 #include "machmode.h"
  28
  29 /* An expanded form of the represented number.  */
  30
  31 /* Enumerate the special cases of numbers that we encounter.  */
  32 enum real_value_class {
  33   rvc_zero,
  34   rvc_normal,
  35   rvc_inf,
  36   rvc_nan
  37 };
  38
  39 #define SIGNIFICAND_BITS        (128 + HOST_BITS_PER_LONG)
  40 #define EXP_BITS                (32 - 6)
  41 #define MAX_EXP                 ((1 << (EXP_BITS - 1)) - 1)
  42 #define SIGSZ                   (SIGNIFICAND_BITS / HOST_BITS_PER_LONG)
  43 #define SIG_MSB                 ((unsigned long)1 << (HOST_BITS_PER_LONG - 1))
  44
  45 struct real_value GTY(())
  46 {
  47   /* Use the same underlying type for all bit-fields, so as to make
  48      sure they're packed together, otherwise REAL_VALUE_TYPE_SIZE will
  49      be miscomputed.  */
  50   unsigned int /* ENUM_BITFIELD (real_value_class) */ cl : 2;
  51   unsigned int decimal : 1;
  52   unsigned int sign : 1;
  53   unsigned int signalling : 1;
  54   unsigned int canonical : 1;
  55   unsigned int uexp : EXP_BITS;
  56   unsigned long sig[SIGSZ];
  57 };
  58
  59 #define REAL_EXP(REAL) \
  60   ((int)((REAL)->uexp ^ (unsigned int)(1 << (EXP_BITS - 1))) \
  61    - (1 << (EXP_BITS - 1)))
  62 #define SET_REAL_EXP(REAL, EXP) \
  63   ((REAL)->uexp = ((unsigned int)(EXP) & (unsigned int)((1 << EXP_BITS) - 1)))
  64
  65 /* Various headers condition prototypes on #ifdef REAL_VALUE_TYPE, so it
  66    needs to be a macro.  We do need to continue to have a structure tag
  67    so that other headers can forward declare it.  */
  68 #define REAL_VALUE_TYPE struct real_value
  69
  70 /* We store a REAL_VALUE_TYPE into an rtx, and we do this by putting it in
  71    consecutive "w" slots.  Moreover, we've got to compute the number of "w"
  72    slots at preprocessor time, which means we can't use sizeof.  Guess.  */
  73
  74 #define REAL_VALUE_TYPE_SIZE (SIGNIFICAND_BITS + 32)
  75 #define REAL_WIDTH \
  76   (REAL_VALUE_TYPE_SIZE/HOST_BITS_PER_WIDE_INT \
  77    + (REAL_VALUE_TYPE_SIZE%HOST_BITS_PER_WIDE_INT ? 1 : 0)) /* round up */
  78
  79 /* Verify the guess.  */
  80 extern char test_real_width
  81   [sizeof(REAL_VALUE_TYPE) <= REAL_WIDTH*sizeof(HOST_WIDE_INT) ? 1 : -1];
  82
  83 /* Calculate the format for CONST_DOUBLE.  We need as many slots as
  84    are necessary to overlay a REAL_VALUE_TYPE on them.  This could be
  85    as many as four (32-bit HOST_WIDE_INT, 128-bit REAL_VALUE_TYPE).
  86
  87    A number of places assume that there are always at least two 'w'
  88    slots in a CONST_DOUBLE, so we provide them even if one would suffice.  */
  89
  90 #if REAL_WIDTH == 1
  91 # define CONST_DOUBLE_FORMAT     "ww"
  92 #else
  93 # if REAL_WIDTH == 2
  94 #  define CONST_DOUBLE_FORMAT    "ww"
  95 # else
  96 #  if REAL_WIDTH == 3
  97 #   define CONST_DOUBLE_FORMAT   "www"
  98 #  else
  99 #   if REAL_WIDTH == 4
 100 #    define CONST_DOUBLE_FORMAT  "wwww"
 101 #   else
 102 #    if REAL_WIDTH == 5
 103 #     define CONST_DOUBLE_FORMAT "wwwww"
 104 #    else
 105 #     if REAL_WIDTH == 6
 106 #      define CONST_DOUBLE_FORMAT "wwwwww"
 107 #     else
 108        #error "REAL_WIDTH > 6 not supported"
 109 #     endif
 110 #    endif
 111 #   endif
 112 #  endif
 113 # endif
 114 #endif
 115
 116
 117 /* Describes the properties of the specific target format in use.  */
 118 struct real_format
 119 {
 120   /* Move to and from the target bytes.  */
 121   void (*encode) (const struct real_format *, long *,
 122                   const REAL_VALUE_TYPE *);
 123   void (*decode) (const struct real_format *, REAL_VALUE_TYPE *,
 124                   const long *);
 125
 126   /* The radix of the exponent and digits of the significand.  */
 127   int b;
 128
 129   /* Size of the significand in digits of radix B.  */
 130   int p;
 131
 132   /* Size of the significant of a NaN, in digits of radix B.  */
 133   int pnan;
 134
 135   /* The minimum negative integer, x, such that b**(x-1) is normalized.  */
 136   int emin;
 137
 138   /* The maximum integer, x, such that b**(x-1) is representable.  */
 139   int emax;
 140
 141   /* The bit position of the sign bit, for determining whether a value
 142      is positive/negative, or -1 for a complex encoding.  */
 143   int signbit_ro;
 144
 145   /* The bit position of the sign bit, for changing the sign of a number,
 146      or -1 for a complex encoding.  */
 147   int signbit_rw;
 148
 149   /* Properties of the format.  */
 150   bool has_nans;
 151   bool has_inf;
 152   bool has_denorm;
 153   bool has_signed_zero;
 154   bool qnan_msb_set;
 155   bool canonical_nan_lsbs_set;
 156 };
 157
 158
 159 /* The target format used for each floating point mode.
 160    Float modes are followed by decimal float modes, with entries for
 161    float modes indexed by (MODE - first float mode), and entries for
 162    decimal float modes indexed by (MODE - first decimal float mode) +
 163    the number of float modes.  */
 164 extern const struct real_format *
 165   real_format_for_mode[MAX_MODE_FLOAT - MIN_MODE_FLOAT + 1
 166                        + MAX_MODE_DECIMAL_FLOAT - MIN_MODE_DECIMAL_FLOAT + 1];
 167
 168 #define REAL_MODE_FORMAT(MODE)                                          \
 169   (real_format_for_mode[DECIMAL_FLOAT_MODE_P (MODE)                     \
 170                         ? ((MODE - MIN_MODE_DECIMAL_FLOAT)              \
 171                            + (MAX_MODE_FLOAT - MIN_MODE_FLOAT + 1))     \
 172                         : (MODE - MIN_MODE_FLOAT)])
 173
 174 /* The following macro determines whether the floating point format is
 175    composite, i.e. may contain non-consecutive mantissa bits, in which
 176    case compile-time FP overflow may not model run-time overflow.  */
 177 #define REAL_MODE_FORMAT_COMPOSITE_P(MODE) \
 178         ((REAL_MODE_FORMAT(MODE))->pnan < (REAL_MODE_FORMAT (MODE))->p)
 179
 180 /* Declare functions in real.c.  */
 181
 182 /* Binary or unary arithmetic on tree_code.  */
 183 extern bool real_arithmetic (REAL_VALUE_TYPE *, int, const REAL_VALUE_TYPE *,
 184                              const REAL_VALUE_TYPE *);
 185
 186 /* Compare reals by tree_code.  */
 187 extern bool real_compare (int, const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 188
 189 /* Determine whether a floating-point value X is infinite.  */
 190 extern bool real_isinf (const REAL_VALUE_TYPE *);
 191
 192 /* Determine whether a floating-point value X is a NaN.  */
 193 extern bool real_isnan (const REAL_VALUE_TYPE *);
 194
 195 /* Determine whether a floating-point value X is negative.  */
 196 extern bool real_isneg (const REAL_VALUE_TYPE *);
 197
 198 /* Determine whether a floating-point value X is minus zero.  */
 199 extern bool real_isnegzero (const REAL_VALUE_TYPE *);
 200
 201 /* Compare two floating-point objects for bitwise identity.  */
 202 extern bool real_identical (const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 203
 204 /* Extend or truncate to a new mode.  */
 205 extern void real_convert (REAL_VALUE_TYPE *, enum machine_mode,
 206                           const REAL_VALUE_TYPE *);
 207
 208 /* Return true if truncating to NEW is exact.  */
 209 extern bool exact_real_truncate (enum machine_mode, const REAL_VALUE_TYPE *);
 210
 211 /* Render R as a decimal floating point constant.  */
 212 extern void real_to_decimal (char *, const REAL_VALUE_TYPE *, size_t,
 213                              size_t, int);
 214
 215 /* Render R as a hexadecimal floating point constant.  */
 216 extern void real_to_hexadecimal (char *, const REAL_VALUE_TYPE *,
 217                                  size_t, size_t, int);
 218
 219 /* Render R as an integer.  */
 220 extern HOST_WIDE_INT real_to_integer (const REAL_VALUE_TYPE *);
 221 extern void real_to_integer2 (HOST_WIDE_INT *, HOST_WIDE_INT *,
 222                               const REAL_VALUE_TYPE *);
 223
 224 /* Initialize R from a decimal or hexadecimal string.  Return -1 if
 225    the value underflows, +1 if overflows, and 0 otherwise.  */
 226 extern int real_from_string (REAL_VALUE_TYPE *, const char *);
 227 /* Wrapper to allow different internal representation for decimal floats. */
 228 extern void real_from_string3 (REAL_VALUE_TYPE *, const char *, enum machine_mode);
 229
 230 /* Initialize R from an integer pair HIGH/LOW.  */
 231 extern void real_from_integer (REAL_VALUE_TYPE *, enum machine_mode,
 232                                unsigned HOST_WIDE_INT, HOST_WIDE_INT, int);
 233
 234 extern long real_to_target_fmt (long *, const REAL_VALUE_TYPE *,
 235                                 const struct real_format *);
 236 extern long real_to_target (long *, const REAL_VALUE_TYPE *, enum machine_mode);
 237
 238 extern void real_from_target_fmt (REAL_VALUE_TYPE *, const long *,
 239                                   const struct real_format *);
 240 extern void real_from_target (REAL_VALUE_TYPE *, const long *,
 241                               enum machine_mode);
 242
 243 extern void real_inf (REAL_VALUE_TYPE *);
 244
 245 extern bool real_nan (REAL_VALUE_TYPE *, const char *, int, enum machine_mode);
 246
 247 extern void real_maxval (REAL_VALUE_TYPE *, int, enum machine_mode);
 248
 249 extern void real_2expN (REAL_VALUE_TYPE *, int);
 250
 251 extern unsigned int real_hash (const REAL_VALUE_TYPE *);
 252
 253
 254 /* Target formats defined in real.c.  */
 255 extern const struct real_format ieee_single_format;
 256 extern const struct real_format mips_single_format;
 257 extern const struct real_format coldfire_single_format;
 258 extern const struct real_format ieee_double_format;
 259 extern const struct real_format mips_double_format;
 260 extern const struct real_format coldfire_double_format;
 261 extern const struct real_format ieee_extended_motorola_format;
 262 extern const struct real_format ieee_extended_intel_96_format;
 263 extern const struct real_format ieee_extended_intel_96_round_53_format;
 264 extern const struct real_format ieee_extended_intel_128_format;
 265 extern const struct real_format ibm_extended_format;
 266 extern const struct real_format mips_extended_format;
 267 extern const struct real_format ieee_quad_format;
 268 extern const struct real_format mips_quad_format;
 269 extern const struct real_format vax_f_format;
 270 extern const struct real_format vax_d_format;
 271 extern const struct real_format vax_g_format;
 272 extern const struct real_format c4x_single_format;
 273 extern const struct real_format c4x_extended_format;
 274 extern const struct real_format real_internal_format;
 275 extern const struct real_format decimal_single_format;
 276 extern const struct real_format decimal_double_format;
 277 extern const struct real_format decimal_quad_format;
 278
 279
 280 /* ====================================================================== */
 281 /* Crap.  */
 282
 283 #define REAL_ARITHMETIC(value, code, d1, d2) \
 284   real_arithmetic (&(value), code, &(d1), &(d2))
 285
 286 #define REAL_VALUES_IDENTICAL(x, y)     real_identical (&(x), &(y))
 287 #define REAL_VALUES_EQUAL(x, y)         real_compare (EQ_EXPR, &(x), &(y))
 288 #define REAL_VALUES_LESS(x, y)          real_compare (LT_EXPR, &(x), &(y))
 289
 290 /* Determine whether a floating-point value X is infinite.  */
 291 #define REAL_VALUE_ISINF(x)             real_isinf (&(x))
 292
 293 /* Determine whether a floating-point value X is a NaN.  */
 294 #define REAL_VALUE_ISNAN(x)             real_isnan (&(x))
 295
 296 /* Determine whether a floating-point value X is negative.  */
 297 #define REAL_VALUE_NEGATIVE(x)          real_isneg (&(x))
 298
 299 /* Determine whether a floating-point value X is minus zero.  */
 300 #define REAL_VALUE_MINUS_ZERO(x)        real_isnegzero (&(x))
 301
 302 /* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
 303 #define REAL_VALUE_TO_TARGET_LONG_DOUBLE(IN, OUT)                       \
 304   real_to_target (OUT, &(IN),                                           \
 305                   mode_for_size (LONG_DOUBLE_TYPE_SIZE, MODE_FLOAT, 0))
 306
 307 #define REAL_VALUE_TO_TARGET_DOUBLE(IN, OUT) \
 308   real_to_target (OUT, &(IN), mode_for_size (64, MODE_FLOAT, 0))
 309
 310 /* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
 311 #define REAL_VALUE_TO_TARGET_SINGLE(IN, OUT) \
 312   ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_FLOAT, 0)))
 313
 314 #define REAL_VALUE_FROM_INT(r, lo, hi, mode) \
 315   real_from_integer (&(r), mode, lo, hi, 0)
 316
 317 #define REAL_VALUE_FROM_UNSIGNED_INT(r, lo, hi, mode) \
 318   real_from_integer (&(r), mode, lo, hi, 1)
 319
 320 /* Real values to IEEE 754R decimal floats.  */
 321
 322 /* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
 323 #define REAL_VALUE_TO_TARGET_DECIMAL128(IN, OUT) \
 324   real_to_target (OUT, &(IN), mode_for_size (128, MODE_DECIMAL_FLOAT, 0))
 325
 326 #define REAL_VALUE_TO_TARGET_DECIMAL64(IN, OUT) \
 327   real_to_target (OUT, &(IN), mode_for_size (64, MODE_DECIMAL_FLOAT, 0))
 328
 329 /* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
 330 #define REAL_VALUE_TO_TARGET_DECIMAL32(IN, OUT) \
 331   ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_DECIMAL_FLOAT, 0)))
 332
 333 extern REAL_VALUE_TYPE real_value_truncate (enum machine_mode,
 334                                             REAL_VALUE_TYPE);
 335
 336 #define REAL_VALUE_TO_INT(plow, phigh, r) \
 337   real_to_integer2 (plow, phigh, &(r))
 338
 339 extern REAL_VALUE_TYPE real_arithmetic2 (int, const REAL_VALUE_TYPE *,
 340                                          const REAL_VALUE_TYPE *);
 341
 342 #define REAL_VALUE_NEGATE(X) \
 343   real_arithmetic2 (NEGATE_EXPR, &(X), NULL)
 344
 345 #define REAL_VALUE_ABS(X) \
 346   real_arithmetic2 (ABS_EXPR, &(X), NULL)
 347
 348 extern int significand_size (enum machine_mode);
 349
 350 extern REAL_VALUE_TYPE real_from_string2 (const char *, enum machine_mode);
 351
 352 #define REAL_VALUE_ATOF(s, m) \
 353   real_from_string2 (s, m)
 354
 355 #define CONST_DOUBLE_ATOF(s, m) \
 356   CONST_DOUBLE_FROM_REAL_VALUE (real_from_string2 (s, m), m)
 357
 358 #define REAL_VALUE_FIX(r) \
 359   real_to_integer (&(r))
 360
 361 /* ??? Not quite right.  */
 362 #define REAL_VALUE_UNSIGNED_FIX(r) \
 363   real_to_integer (&(r))
 364
 365 /* ??? These were added for Paranoia support.  */
 366
 367 /* Return floor log2(R).  */
 368 extern int real_exponent (const REAL_VALUE_TYPE *);
 369
 370 /* R = A * 2**EXP.  */
 371 extern void real_ldexp (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *, int);
 372
 373 /* **** End of software floating point emulator interface macros **** */
 374 \f
 375 /* Constant real values 0, 1, 2, 3, 10, -1, -2, 0.5 and 1/3.  */
 376
 377 extern REAL_VALUE_TYPE dconst0;
 378 extern REAL_VALUE_TYPE dconst1;
 379 extern REAL_VALUE_TYPE dconst2;
 380 extern REAL_VALUE_TYPE dconst3;
 381 extern REAL_VALUE_TYPE dconst10;
 382 extern REAL_VALUE_TYPE dconstm1;
 383 extern REAL_VALUE_TYPE dconstm2;
 384 extern REAL_VALUE_TYPE dconsthalf;
 385 extern REAL_VALUE_TYPE dconstthird;
 386 extern REAL_VALUE_TYPE dconstsqrt2;
 387 extern REAL_VALUE_TYPE dconste;
 388
 389 /* Function to return a real value (not a tree node)
 390    from a given integer constant.  */
 391 REAL_VALUE_TYPE real_value_from_int_cst (tree, tree);
 392
 393 /* Given a CONST_DOUBLE in FROM, store into TO the value it represents.  */
 394 #define REAL_VALUE_FROM_CONST_DOUBLE(to, from) \
 395   ((to) = *CONST_DOUBLE_REAL_VALUE (from))
 396
 397 /* Return a CONST_DOUBLE with value R and mode M.  */
 398 #define CONST_DOUBLE_FROM_REAL_VALUE(r, m) \
 399   const_double_from_real_value (r, m)
 400 extern rtx const_double_from_real_value (REAL_VALUE_TYPE, enum machine_mode);
 401
 402 /* Replace R by 1/R in the given machine mode, if the result is exact.  */
 403 extern bool exact_real_inverse (enum machine_mode, REAL_VALUE_TYPE *);
 404
 405 /* In tree.c: wrap up a REAL_VALUE_TYPE in a tree node.  */
 406 extern tree build_real (tree, REAL_VALUE_TYPE);
 407
 408 /* Calculate R as the square root of X in the given machine mode.  */
 409 extern bool real_sqrt (REAL_VALUE_TYPE *, enum machine_mode,
 410                        const REAL_VALUE_TYPE *);
 411
 412 /* Calculate R as X raised to the integer exponent N in mode MODE.  */
 413 extern bool real_powi (REAL_VALUE_TYPE *, enum machine_mode,
 414                        const REAL_VALUE_TYPE *, HOST_WIDE_INT);
 415
 416 /* Standard round to integer value functions.  */
 417 extern void real_trunc (REAL_VALUE_TYPE *, enum machine_mode,
 418                         const REAL_VALUE_TYPE *);
 419 extern void real_floor (REAL_VALUE_TYPE *, enum machine_mode,
 420                         const REAL_VALUE_TYPE *);
 421 extern void real_ceil (REAL_VALUE_TYPE *, enum machine_mode,
 422                        const REAL_VALUE_TYPE *);
 423 extern void real_round (REAL_VALUE_TYPE *, enum machine_mode,
 424                         const REAL_VALUE_TYPE *);
 425
 426 /* Set the sign of R to the sign of X.  */
 427 extern void real_copysign (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 428
 429 /* Convert between MPFR and REAL_VALUE_TYPE.  The caller is
 430    responsible for initializing and clearing the MPFR parameter.  */
 431
 432 extern void real_from_mpfr (REAL_VALUE_TYPE *, mpfr_srcptr, tree, mp_rnd_t);
 433 extern void mpfr_from_real (mpfr_ptr, const REAL_VALUE_TYPE *, mp_rnd_t);
 434
 435 /* Check whether the real constant value given is an integer.  */
 436 extern bool real_isinteger (const REAL_VALUE_TYPE *c, enum machine_mode mode);
 437
 438 #endif /* ! GCC_REAL_H */