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   bool canonical_nan_lsbs_set;
 159 };
 160
 161
 162 /* The target format used for each floating point mode.
 163    Float modes are followed by decimal float modes, with entries for
 164    float modes indexed by (MODE - first float mode), and entries for
 165    decimal float modes indexed by (MODE - first decimal float mode) +
 166    the number of float modes.  */
 167 extern const struct real_format *
 168   real_format_for_mode[MAX_MODE_FLOAT - MIN_MODE_FLOAT + 1
 169                        + MAX_MODE_DECIMAL_FLOAT - MIN_MODE_DECIMAL_FLOAT + 1];
 170
 171 #define REAL_MODE_FORMAT(MODE)                                          \
 172   (real_format_for_mode[DECIMAL_FLOAT_MODE_P (MODE)                     \
 173                         ? ((MODE - MIN_MODE_DECIMAL_FLOAT)              \
 174                            + (MAX_MODE_FLOAT - MIN_MODE_FLOAT + 1))     \
 175                         : (MODE - MIN_MODE_FLOAT)])
 176
 177 /* The following macro determines whether the floating point format is
 178    composite, i.e. may contain non-consecutive mantissa bits, in which
 179    case compile-time FP overflow may not model run-time overflow.  */
 180 #define REAL_MODE_FORMAT_COMPOSITE_P(MODE) \
 181         ((REAL_MODE_FORMAT(MODE))->pnan < (REAL_MODE_FORMAT (MODE))->p)
 182
 183 /* Declare functions in real.c.  */
 184
 185 /* Binary or unary arithmetic on tree_code.  */
 186 extern bool real_arithmetic (REAL_VALUE_TYPE *, int, const REAL_VALUE_TYPE *,
 187                              const REAL_VALUE_TYPE *);
 188
 189 /* Compare reals by tree_code.  */
 190 extern bool real_compare (int, const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 191
 192 /* Determine whether a floating-point value X is infinite.  */
 193 extern bool real_isinf (const REAL_VALUE_TYPE *);
 194
 195 /* Determine whether a floating-point value X is a NaN.  */
 196 extern bool real_isnan (const REAL_VALUE_TYPE *);
 197
 198 /* Determine whether a floating-point value X is negative.  */
 199 extern bool real_isneg (const REAL_VALUE_TYPE *);
 200
 201 /* Determine whether a floating-point value X is minus zero.  */
 202 extern bool real_isnegzero (const REAL_VALUE_TYPE *);
 203
 204 /* Compare two floating-point objects for bitwise identity.  */
 205 extern bool real_identical (const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 206
 207 /* Extend or truncate to a new mode.  */
 208 extern void real_convert (REAL_VALUE_TYPE *, enum machine_mode,
 209                           const REAL_VALUE_TYPE *);
 210
 211 /* Return true if truncating to NEW is exact.  */
 212 extern bool exact_real_truncate (enum machine_mode, const REAL_VALUE_TYPE *);
 213
 214 /* Render R as a decimal floating point constant.  */
 215 extern void real_to_decimal (char *, const REAL_VALUE_TYPE *, size_t,
 216                              size_t, int);
 217
 218 /* Render R as a hexadecimal floating point constant.  */
 219 extern void real_to_hexadecimal (char *, const REAL_VALUE_TYPE *,
 220                                  size_t, size_t, int);
 221
 222 /* Render R as an integer.  */
 223 extern HOST_WIDE_INT real_to_integer (const REAL_VALUE_TYPE *);
 224 extern void real_to_integer2 (HOST_WIDE_INT *, HOST_WIDE_INT *,
 225                               const REAL_VALUE_TYPE *);
 226
 227 /* Initialize R from a decimal or hexadecimal string.  */
 228 extern void real_from_string (REAL_VALUE_TYPE *, const char *);
 229 /* Wrapper to allow different internal representation for decimal floats. */
 230 extern void real_from_string3 (REAL_VALUE_TYPE *, const char *, enum machine_mode);
 231
 232 /* Initialize R from an integer pair HIGH/LOW.  */
 233 extern void real_from_integer (REAL_VALUE_TYPE *, enum machine_mode,
 234                                unsigned HOST_WIDE_INT, HOST_WIDE_INT, int);
 235
 236 extern long real_to_target_fmt (long *, const REAL_VALUE_TYPE *,
 237                                 const struct real_format *);
 238 extern long real_to_target (long *, const REAL_VALUE_TYPE *, enum machine_mode);
 239
 240 extern void real_from_target_fmt (REAL_VALUE_TYPE *, const long *,
 241                                   const struct real_format *);
 242 extern void real_from_target (REAL_VALUE_TYPE *, const long *,
 243                               enum machine_mode);
 244
 245 extern void real_inf (REAL_VALUE_TYPE *);
 246
 247 extern bool real_nan (REAL_VALUE_TYPE *, const char *, int, enum machine_mode);
 248
 249 extern void real_maxval (REAL_VALUE_TYPE *, int, enum machine_mode);
 250
 251 extern void real_2expN (REAL_VALUE_TYPE *, int);
 252
 253 extern unsigned int real_hash (const REAL_VALUE_TYPE *);
 254
 255
 256 /* Target formats defined in real.c.  */
 257 extern const struct real_format ieee_single_format;
 258 extern const struct real_format mips_single_format;
 259 extern const struct real_format coldfire_single_format;
 260 extern const struct real_format ieee_double_format;
 261 extern const struct real_format mips_double_format;
 262 extern const struct real_format coldfire_double_format;
 263 extern const struct real_format ieee_extended_motorola_format;
 264 extern const struct real_format ieee_extended_intel_96_format;
 265 extern const struct real_format ieee_extended_intel_96_round_53_format;
 266 extern const struct real_format ieee_extended_intel_128_format;
 267 extern const struct real_format ibm_extended_format;
 268 extern const struct real_format mips_extended_format;
 269 extern const struct real_format ieee_quad_format;
 270 extern const struct real_format mips_quad_format;
 271 extern const struct real_format vax_f_format;
 272 extern const struct real_format vax_d_format;
 273 extern const struct real_format vax_g_format;
 274 extern const struct real_format i370_single_format;
 275 extern const struct real_format i370_double_format;
 276 extern const struct real_format c4x_single_format;
 277 extern const struct real_format c4x_extended_format;
 278 extern const struct real_format real_internal_format;
 279 extern const struct real_format decimal_single_format;
 280 extern const struct real_format decimal_double_format;
 281 extern const struct real_format decimal_quad_format;
 282
 283
 284 /* ====================================================================== */
 285 /* Crap.  */
 286
 287 #define REAL_ARITHMETIC(value, code, d1, d2) \
 288   real_arithmetic (&(value), code, &(d1), &(d2))
 289
 290 #define REAL_VALUES_IDENTICAL(x, y)     real_identical (&(x), &(y))
 291 #define REAL_VALUES_EQUAL(x, y)         real_compare (EQ_EXPR, &(x), &(y))
 292 #define REAL_VALUES_LESS(x, y)          real_compare (LT_EXPR, &(x), &(y))
 293
 294 /* Determine whether a floating-point value X is infinite.  */
 295 #define REAL_VALUE_ISINF(x)             real_isinf (&(x))
 296
 297 /* Determine whether a floating-point value X is a NaN.  */
 298 #define REAL_VALUE_ISNAN(x)             real_isnan (&(x))
 299
 300 /* Determine whether a floating-point value X is negative.  */
 301 #define REAL_VALUE_NEGATIVE(x)          real_isneg (&(x))
 302
 303 /* Determine whether a floating-point value X is minus zero.  */
 304 #define REAL_VALUE_MINUS_ZERO(x)        real_isnegzero (&(x))
 305
 306 /* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
 307 #define REAL_VALUE_TO_TARGET_LONG_DOUBLE(IN, OUT)                       \
 308   real_to_target (OUT, &(IN),                                           \
 309                   mode_for_size (LONG_DOUBLE_TYPE_SIZE, MODE_FLOAT, 0))
 310
 311 #define REAL_VALUE_TO_TARGET_DOUBLE(IN, OUT) \
 312   real_to_target (OUT, &(IN), mode_for_size (64, MODE_FLOAT, 0))
 313
 314 /* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
 315 #define REAL_VALUE_TO_TARGET_SINGLE(IN, OUT) \
 316   ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_FLOAT, 0)))
 317
 318 #define REAL_VALUE_FROM_INT(r, lo, hi, mode) \
 319   real_from_integer (&(r), mode, lo, hi, 0)
 320
 321 #define REAL_VALUE_FROM_UNSIGNED_INT(r, lo, hi, mode) \
 322   real_from_integer (&(r), mode, lo, hi, 1)
 323
 324 /* Real values to IEEE 754R decimal floats.  */
 325
 326 /* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
 327 #define REAL_VALUE_TO_TARGET_DECIMAL128(IN, OUT) \
 328   real_to_target (OUT, &(IN), mode_for_size (128, MODE_DECIMAL_FLOAT, 0))
 329
 330 #define REAL_VALUE_TO_TARGET_DECIMAL64(IN, OUT) \
 331   real_to_target (OUT, &(IN), mode_for_size (64, MODE_DECIMAL_FLOAT, 0))
 332
 333 /* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
 334 #define REAL_VALUE_TO_TARGET_DECIMAL32(IN, OUT) \
 335   ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_DECIMAL_FLOAT, 0)))
 336
 337 extern REAL_VALUE_TYPE real_value_truncate (enum machine_mode,
 338                                             REAL_VALUE_TYPE);
 339
 340 #define REAL_VALUE_TO_INT(plow, phigh, r) \
 341   real_to_integer2 (plow, phigh, &(r))
 342
 343 extern REAL_VALUE_TYPE real_arithmetic2 (int, const REAL_VALUE_TYPE *,
 344                                          const REAL_VALUE_TYPE *);
 345
 346 #define REAL_VALUE_NEGATE(X) \
 347   real_arithmetic2 (NEGATE_EXPR, &(X), NULL)
 348
 349 #define REAL_VALUE_ABS(X) \
 350   real_arithmetic2 (ABS_EXPR, &(X), NULL)
 351
 352 extern int significand_size (enum machine_mode);
 353
 354 extern REAL_VALUE_TYPE real_from_string2 (const char *, enum machine_mode);
 355
 356 #define REAL_VALUE_ATOF(s, m) \
 357   real_from_string2 (s, m)
 358
 359 #define CONST_DOUBLE_ATOF(s, m) \
 360   CONST_DOUBLE_FROM_REAL_VALUE (real_from_string2 (s, m), m)
 361
 362 #define REAL_VALUE_FIX(r) \
 363   real_to_integer (&(r))
 364
 365 /* ??? Not quite right.  */
 366 #define REAL_VALUE_UNSIGNED_FIX(r) \
 367   real_to_integer (&(r))
 368
 369 /* ??? These were added for Paranoia support.  */
 370
 371 /* Return floor log2(R).  */
 372 extern int real_exponent (const REAL_VALUE_TYPE *);
 373
 374 /* R = A * 2**EXP.  */
 375 extern void real_ldexp (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *, int);
 376
 377 /* **** End of software floating point emulator interface macros **** */
 378 \f
 379 /* Constant real values 0, 1, 2, 3, 10, -1, -2, 0.5 and 1/3.  */
 380
 381 extern REAL_VALUE_TYPE dconst0;
 382 extern REAL_VALUE_TYPE dconst1;
 383 extern REAL_VALUE_TYPE dconst2;
 384 extern REAL_VALUE_TYPE dconst3;
 385 extern REAL_VALUE_TYPE dconst10;
 386 extern REAL_VALUE_TYPE dconstm1;
 387 extern REAL_VALUE_TYPE dconstm2;
 388 extern REAL_VALUE_TYPE dconsthalf;
 389 extern REAL_VALUE_TYPE dconstthird;
 390 extern REAL_VALUE_TYPE dconstsqrt2;
 391 extern REAL_VALUE_TYPE dconste;
 392
 393 /* Function to return a real value (not a tree node)
 394    from a given integer constant.  */
 395 REAL_VALUE_TYPE real_value_from_int_cst (tree, tree);
 396
 397 /* Given a CONST_DOUBLE in FROM, store into TO the value it represents.  */
 398 #define REAL_VALUE_FROM_CONST_DOUBLE(to, from) \
 399   ((to) = *CONST_DOUBLE_REAL_VALUE (from))
 400
 401 /* Return a CONST_DOUBLE with value R and mode M.  */
 402 #define CONST_DOUBLE_FROM_REAL_VALUE(r, m) \
 403   const_double_from_real_value (r, m)
 404 extern rtx const_double_from_real_value (REAL_VALUE_TYPE, enum machine_mode);
 405
 406 /* Replace R by 1/R in the given machine mode, if the result is exact.  */
 407 extern bool exact_real_inverse (enum machine_mode, REAL_VALUE_TYPE *);
 408
 409 /* In tree.c: wrap up a REAL_VALUE_TYPE in a tree node.  */
 410 extern tree build_real (tree, REAL_VALUE_TYPE);
 411
 412 /* Calculate R as the square root of X in the given machine mode.  */
 413 extern bool real_sqrt (REAL_VALUE_TYPE *, enum machine_mode,
 414                        const REAL_VALUE_TYPE *);
 415
 416 /* Calculate R as X raised to the integer exponent N in mode MODE.  */
 417 extern bool real_powi (REAL_VALUE_TYPE *, enum machine_mode,
 418                        const REAL_VALUE_TYPE *, HOST_WIDE_INT);
 419
 420 /* Standard round to integer value functions.  */
 421 extern void real_trunc (REAL_VALUE_TYPE *, enum machine_mode,
 422                         const REAL_VALUE_TYPE *);
 423 extern void real_floor (REAL_VALUE_TYPE *, enum machine_mode,
 424                         const REAL_VALUE_TYPE *);
 425 extern void real_ceil (REAL_VALUE_TYPE *, enum machine_mode,
 426                        const REAL_VALUE_TYPE *);
 427 extern void real_round (REAL_VALUE_TYPE *, enum machine_mode,
 428                         const REAL_VALUE_TYPE *);
 429
 430 /* Set the sign of R to the sign of X.  */
 431 extern void real_copysign (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 432
 433 /* Convert between MPFR and REAL_VALUE_TYPE.  The caller is
 434    responsible for initializing and clearing the MPFR parameter.  */
 435
 436 extern void real_from_mpfr (REAL_VALUE_TYPE *, mpfr_srcptr);
 437 extern void mpfr_from_real (mpfr_ptr, const REAL_VALUE_TYPE *);
 438
 439 /* Check whether the real constant value given is an integer.  */
 440 extern bool real_isinteger (const REAL_VALUE_TYPE *c, enum machine_mode mode);
 441
 442 #endif /* ! GCC_REAL_H */