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   /* log2(b).  */
 130   int log2_b;
 131
 132   /* Size of the significand in digits of radix B.  */
 133   int p;
 134
 135   /* Size of the significant of a NaN, in digits of radix B.  */
 136   int pnan;
 137
 138   /* The minimum negative integer, x, such that b**(x-1) is normalized.  */
 139   int emin;
 140
 141   /* The maximum integer, x, such that b**(x-1) is representable.  */
 142   int emax;
 143
 144   /* The bit position of the sign bit, for determining whether a value
 145      is positive/negative, or -1 for a complex encoding.  */
 146   int signbit_ro;
 147
 148   /* The bit position of the sign bit, for changing the sign of a number,
 149      or -1 for a complex encoding.  */
 150   int signbit_rw;
 151
 152   /* Properties of the format.  */
 153   bool has_nans;
 154   bool has_inf;
 155   bool has_denorm;
 156   bool has_signed_zero;
 157   bool qnan_msb_set;
 158 };
 159
 160
 161 /* The target format used for each floating point mode.
 162    Float modes are followed by decimal float modes, with entries for
 163    float modes indexed by (MODE - first float mode), and entries for
 164    decimal float modes indexed by (MODE - first decimal float mode) +
 165    the number of float modes.  */
 166 extern const struct real_format *
 167   real_format_for_mode[MAX_MODE_FLOAT - MIN_MODE_FLOAT + 1
 168                        + MAX_MODE_DECIMAL_FLOAT - MIN_MODE_DECIMAL_FLOAT + 1];
 169
 170 #define REAL_MODE_FORMAT(MODE)                                          \
 171   (real_format_for_mode[DECIMAL_FLOAT_MODE_P (MODE)                     \
 172                         ? ((MODE - MIN_MODE_DECIMAL_FLOAT)              \
 173                            + (MAX_MODE_FLOAT - MIN_MODE_FLOAT + 1))     \
 174                         : (MODE - MIN_MODE_FLOAT)])
 175
 176 /* The following macro determines whether the floating point format is
 177    composite, i.e. may contain non-consecutive mantissa bits, in which
 178    case compile-time FP overflow may not model run-time overflow.  */
 179 #define REAL_MODE_FORMAT_COMPOSITE_P(MODE) \
 180         ((REAL_MODE_FORMAT(MODE))->pnan < (REAL_MODE_FORMAT (MODE))->p)
 181
 182 /* Declare functions in real.c.  */
 183
 184 /* Binary or unary arithmetic on tree_code.  */
 185 extern bool real_arithmetic (REAL_VALUE_TYPE *, int, const REAL_VALUE_TYPE *,
 186                              const REAL_VALUE_TYPE *);
 187
 188 /* Compare reals by tree_code.  */
 189 extern bool real_compare (int, const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 190
 191 /* Determine whether a floating-point value X is infinite.  */
 192 extern bool real_isinf (const REAL_VALUE_TYPE *);
 193
 194 /* Determine whether a floating-point value X is a NaN.  */
 195 extern bool real_isnan (const REAL_VALUE_TYPE *);
 196
 197 /* Determine whether a floating-point value X is negative.  */
 198 extern bool real_isneg (const REAL_VALUE_TYPE *);
 199
 200 /* Determine whether a floating-point value X is minus zero.  */
 201 extern bool real_isnegzero (const REAL_VALUE_TYPE *);
 202
 203 /* Compare two floating-point objects for bitwise identity.  */
 204 extern bool real_identical (const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 205
 206 /* Extend or truncate to a new mode.  */
 207 extern void real_convert (REAL_VALUE_TYPE *, enum machine_mode,
 208                           const REAL_VALUE_TYPE *);
 209
 210 /* Return true if truncating to NEW is exact.  */
 211 extern bool exact_real_truncate (enum machine_mode, const REAL_VALUE_TYPE *);
 212
 213 /* Render R as a decimal floating point constant.  */
 214 extern void real_to_decimal (char *, const REAL_VALUE_TYPE *, size_t,
 215                              size_t, int);
 216
 217 /* Render R as a hexadecimal floating point constant.  */
 218 extern void real_to_hexadecimal (char *, const REAL_VALUE_TYPE *,
 219                                  size_t, size_t, int);
 220
 221 /* Render R as an integer.  */
 222 extern HOST_WIDE_INT real_to_integer (const REAL_VALUE_TYPE *);
 223 extern void real_to_integer2 (HOST_WIDE_INT *, HOST_WIDE_INT *,
 224                               const REAL_VALUE_TYPE *);
 225
 226 /* Initialize R from a decimal or hexadecimal string.  */
 227 extern void real_from_string (REAL_VALUE_TYPE *, const char *);
 228 /* Wrapper to allow different internal representation for decimal floats. */
 229 extern void real_from_string3 (REAL_VALUE_TYPE *, const char *, enum machine_mode);
 230
 231 /* Initialize R from an integer pair HIGH/LOW.  */
 232 extern void real_from_integer (REAL_VALUE_TYPE *, enum machine_mode,
 233                                unsigned HOST_WIDE_INT, HOST_WIDE_INT, int);
 234
 235 extern long real_to_target_fmt (long *, const REAL_VALUE_TYPE *,
 236                                 const struct real_format *);
 237 extern long real_to_target (long *, const REAL_VALUE_TYPE *, enum machine_mode);
 238
 239 extern void real_from_target_fmt (REAL_VALUE_TYPE *, const long *,
 240                                   const struct real_format *);
 241 extern void real_from_target (REAL_VALUE_TYPE *, const long *,
 242                               enum machine_mode);
 243
 244 extern void real_inf (REAL_VALUE_TYPE *);
 245
 246 extern bool real_nan (REAL_VALUE_TYPE *, const char *, int, enum machine_mode);
 247
 248 extern void real_maxval (REAL_VALUE_TYPE *, int, enum machine_mode);
 249
 250 extern void real_2expN (REAL_VALUE_TYPE *, int);
 251
 252 extern unsigned int real_hash (const REAL_VALUE_TYPE *);
 253
 254
 255 /* Target formats defined in real.c.  */
 256 extern const struct real_format ieee_single_format;
 257 extern const struct real_format mips_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 ieee_extended_motorola_format;
 261 extern const struct real_format ieee_extended_intel_96_format;
 262 extern const struct real_format ieee_extended_intel_96_round_53_format;
 263 extern const struct real_format ieee_extended_intel_128_format;
 264 extern const struct real_format ibm_extended_format;
 265 extern const struct real_format mips_extended_format;
 266 extern const struct real_format ieee_quad_format;
 267 extern const struct real_format mips_quad_format;
 268 extern const struct real_format vax_f_format;
 269 extern const struct real_format vax_d_format;
 270 extern const struct real_format vax_g_format;
 271 extern const struct real_format i370_single_format;
 272 extern const struct real_format i370_double_format;
 273 extern const struct real_format c4x_single_format;
 274 extern const struct real_format c4x_extended_format;
 275 extern const struct real_format real_internal_format;
 276 extern const struct real_format decimal_single_format;
 277 extern const struct real_format decimal_double_format;
 278 extern const struct real_format decimal_quad_format;
 279
 280
 281 /* ====================================================================== */
 282 /* Crap.  */
 283
 284 #define REAL_ARITHMETIC(value, code, d1, d2) \
 285   real_arithmetic (&(value), code, &(d1), &(d2))
 286
 287 #define REAL_VALUES_IDENTICAL(x, y)     real_identical (&(x), &(y))
 288 #define REAL_VALUES_EQUAL(x, y)         real_compare (EQ_EXPR, &(x), &(y))
 289 #define REAL_VALUES_LESS(x, y)          real_compare (LT_EXPR, &(x), &(y))
 290
 291 /* Determine whether a floating-point value X is infinite.  */
 292 #define REAL_VALUE_ISINF(x)             real_isinf (&(x))
 293
 294 /* Determine whether a floating-point value X is a NaN.  */
 295 #define REAL_VALUE_ISNAN(x)             real_isnan (&(x))
 296
 297 /* Determine whether a floating-point value X is negative.  */
 298 #define REAL_VALUE_NEGATIVE(x)          real_isneg (&(x))
 299
 300 /* Determine whether a floating-point value X is minus zero.  */
 301 #define REAL_VALUE_MINUS_ZERO(x)        real_isnegzero (&(x))
 302
 303 /* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
 304 #define REAL_VALUE_TO_TARGET_LONG_DOUBLE(IN, OUT)                       \
 305   real_to_target (OUT, &(IN),                                           \
 306                   mode_for_size (LONG_DOUBLE_TYPE_SIZE, MODE_FLOAT, 0))
 307
 308 #define REAL_VALUE_TO_TARGET_DOUBLE(IN, OUT) \
 309   real_to_target (OUT, &(IN), mode_for_size (64, MODE_FLOAT, 0))
 310
 311 /* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
 312 #define REAL_VALUE_TO_TARGET_SINGLE(IN, OUT) \
 313   ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_FLOAT, 0)))
 314
 315 #define REAL_VALUE_FROM_INT(r, lo, hi, mode) \
 316   real_from_integer (&(r), mode, lo, hi, 0)
 317
 318 #define REAL_VALUE_FROM_UNSIGNED_INT(r, lo, hi, mode) \
 319   real_from_integer (&(r), mode, lo, hi, 1)
 320
 321 /* Real values to IEEE 754R decimal floats.  */
 322
 323 /* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
 324 #define REAL_VALUE_TO_TARGET_DECIMAL128(IN, OUT) \
 325   real_to_target (OUT, &(IN), mode_for_size (128, MODE_DECIMAL_FLOAT, 0))
 326
 327 #define REAL_VALUE_TO_TARGET_DECIMAL64(IN, OUT) \
 328   real_to_target (OUT, &(IN), mode_for_size (64, MODE_DECIMAL_FLOAT, 0))
 329
 330 /* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
 331 #define REAL_VALUE_TO_TARGET_DECIMAL32(IN, OUT) \
 332   ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_DECIMAL_FLOAT, 0)))
 333
 334 extern REAL_VALUE_TYPE real_value_truncate (enum machine_mode,
 335                                             REAL_VALUE_TYPE);
 336
 337 #define REAL_VALUE_TO_INT(plow, phigh, r) \
 338   real_to_integer2 (plow, phigh, &(r))
 339
 340 extern REAL_VALUE_TYPE real_arithmetic2 (int, const REAL_VALUE_TYPE *,
 341                                          const REAL_VALUE_TYPE *);
 342
 343 #define REAL_VALUE_NEGATE(X) \
 344   real_arithmetic2 (NEGATE_EXPR, &(X), NULL)
 345
 346 #define REAL_VALUE_ABS(X) \
 347   real_arithmetic2 (ABS_EXPR, &(X), NULL)
 348
 349 extern int significand_size (enum machine_mode);
 350
 351 extern REAL_VALUE_TYPE real_from_string2 (const char *, enum machine_mode);
 352
 353 #define REAL_VALUE_ATOF(s, m) \
 354   real_from_string2 (s, m)
 355
 356 #define CONST_DOUBLE_ATOF(s, m) \
 357   CONST_DOUBLE_FROM_REAL_VALUE (real_from_string2 (s, m), m)
 358
 359 #define REAL_VALUE_FIX(r) \
 360   real_to_integer (&(r))
 361
 362 /* ??? Not quite right.  */
 363 #define REAL_VALUE_UNSIGNED_FIX(r) \
 364   real_to_integer (&(r))
 365
 366 /* ??? These were added for Paranoia support.  */
 367
 368 /* Return floor log2(R).  */
 369 extern int real_exponent (const REAL_VALUE_TYPE *);
 370
 371 /* R = A * 2**EXP.  */
 372 extern void real_ldexp (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *, int);
 373
 374 /* **** End of software floating point emulator interface macros **** */
 375 \f
 376 /* Constant real values 0, 1, 2, 3, 10, -1, -2, 0.5 and 1/3.  */
 377
 378 extern REAL_VALUE_TYPE dconst0;
 379 extern REAL_VALUE_TYPE dconst1;
 380 extern REAL_VALUE_TYPE dconst2;
 381 extern REAL_VALUE_TYPE dconst3;
 382 extern REAL_VALUE_TYPE dconst10;
 383 extern REAL_VALUE_TYPE dconstm1;
 384 extern REAL_VALUE_TYPE dconstm2;
 385 extern REAL_VALUE_TYPE dconsthalf;
 386 extern REAL_VALUE_TYPE dconstthird;
 387 extern REAL_VALUE_TYPE dconstpi;
 388 extern REAL_VALUE_TYPE dconste;
 389
 390 /* Function to return a real value (not a tree node)
 391    from a given integer constant.  */
 392 REAL_VALUE_TYPE real_value_from_int_cst (tree, tree);
 393
 394 /* Given a CONST_DOUBLE in FROM, store into TO the value it represents.  */
 395 #define REAL_VALUE_FROM_CONST_DOUBLE(to, from) \
 396   ((to) = *CONST_DOUBLE_REAL_VALUE (from))
 397
 398 /* Return a CONST_DOUBLE with value R and mode M.  */
 399 #define CONST_DOUBLE_FROM_REAL_VALUE(r, m) \
 400   const_double_from_real_value (r, m)
 401 extern rtx const_double_from_real_value (REAL_VALUE_TYPE, enum machine_mode);
 402
 403 /* Replace R by 1/R in the given machine mode, if the result is exact.  */
 404 extern bool exact_real_inverse (enum machine_mode, REAL_VALUE_TYPE *);
 405
 406 /* In tree.c: wrap up a REAL_VALUE_TYPE in a tree node.  */
 407 extern tree build_real (tree, REAL_VALUE_TYPE);
 408
 409 /* Calculate R as the square root of X in the given machine mode.  */
 410 extern bool real_sqrt (REAL_VALUE_TYPE *, enum machine_mode,
 411                        const REAL_VALUE_TYPE *);
 412
 413 /* Calculate R as X raised to the integer exponent N in mode MODE.  */
 414 extern bool real_powi (REAL_VALUE_TYPE *, enum machine_mode,
 415                        const REAL_VALUE_TYPE *, HOST_WIDE_INT);
 416
 417 /* Standard round to integer value functions.  */
 418 extern void real_trunc (REAL_VALUE_TYPE *, enum machine_mode,
 419                         const REAL_VALUE_TYPE *);
 420 extern void real_floor (REAL_VALUE_TYPE *, enum machine_mode,
 421                         const REAL_VALUE_TYPE *);
 422 extern void real_ceil (REAL_VALUE_TYPE *, enum machine_mode,
 423                        const REAL_VALUE_TYPE *);
 424 extern void real_round (REAL_VALUE_TYPE *, enum machine_mode,
 425                         const REAL_VALUE_TYPE *);
 426
 427 /* Set the sign of R to the sign of X.  */
 428 extern void real_copysign (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 429
 430 /* Convert between MPFR and REAL_VALUE_TYPE.  The caller is
 431    responsible for initializing and clearing the MPFR parameter.  */
 432
 433 extern void real_from_mpfr (REAL_VALUE_TYPE *, mpfr_srcptr);
 434 extern void mpfr_from_real (mpfr_ptr, const REAL_VALUE_TYPE *);
 435
 436 /* Check whether the real constant value given is an integer.  */
 437 extern bool real_isinteger (const REAL_VALUE_TYPE *c, enum machine_mode mode);
 438
 439 #endif /* ! GCC_REAL_H */