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, 2007, 2008 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 3, 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 COPYING3.  If not see
  19    <http://www.gnu.org/licenses/>.  */
  20
  21 #ifndef GCC_REAL_H
  22 #define GCC_REAL_H
  23
  24 #ifndef GENERATOR_FILE
  25 #include <gmp.h>
  26 #include <mpfr.h>
  27 #endif
  28 #include "machmode.h"
  29
  30 /* An expanded form of the represented number.  */
  31
  32 /* Enumerate the special cases of numbers that we encounter.  */
  33 enum real_value_class {
  34   rvc_zero,
  35   rvc_normal,
  36   rvc_inf,
  37   rvc_nan
  38 };
  39
  40 #define SIGNIFICAND_BITS        (128 + HOST_BITS_PER_LONG)
  41 #define EXP_BITS                (32 - 6)
  42 #define MAX_EXP                 ((1 << (EXP_BITS - 1)) - 1)
  43 #define SIGSZ                   (SIGNIFICAND_BITS / HOST_BITS_PER_LONG)
  44 #define SIG_MSB                 ((unsigned long)1 << (HOST_BITS_PER_LONG - 1))
  45
  46 struct real_value GTY(())
  47 {
  48   /* Use the same underlying type for all bit-fields, so as to make
  49      sure they're packed together, otherwise REAL_VALUE_TYPE_SIZE will
  50      be miscomputed.  */
  51   unsigned int /* ENUM_BITFIELD (real_value_class) */ cl : 2;
  52   unsigned int decimal : 1;
  53   unsigned int sign : 1;
  54   unsigned int signalling : 1;
  55   unsigned int canonical : 1;
  56   unsigned int uexp : EXP_BITS;
  57   unsigned long sig[SIGSZ];
  58 };
  59
  60 #define REAL_EXP(REAL) \
  61   ((int)((REAL)->uexp ^ (unsigned int)(1 << (EXP_BITS - 1))) \
  62    - (1 << (EXP_BITS - 1)))
  63 #define SET_REAL_EXP(REAL, EXP) \
  64   ((REAL)->uexp = ((unsigned int)(EXP) & (unsigned int)((1 << EXP_BITS) - 1)))
  65
  66 /* Various headers condition prototypes on #ifdef REAL_VALUE_TYPE, so it
  67    needs to be a macro.  We do need to continue to have a structure tag
  68    so that other headers can forward declare it.  */
  69 #define REAL_VALUE_TYPE struct real_value
  70
  71 /* We store a REAL_VALUE_TYPE into an rtx, and we do this by putting it in
  72    consecutive "w" slots.  Moreover, we've got to compute the number of "w"
  73    slots at preprocessor time, which means we can't use sizeof.  Guess.  */
  74
  75 #define REAL_VALUE_TYPE_SIZE (SIGNIFICAND_BITS + 32)
  76 #define REAL_WIDTH \
  77   (REAL_VALUE_TYPE_SIZE/HOST_BITS_PER_WIDE_INT \
  78    + (REAL_VALUE_TYPE_SIZE%HOST_BITS_PER_WIDE_INT ? 1 : 0)) /* round up */
  79
  80 /* Verify the guess.  */
  81 extern char test_real_width
  82   [sizeof(REAL_VALUE_TYPE) <= REAL_WIDTH*sizeof(HOST_WIDE_INT) ? 1 : -1];
  83
  84 /* Calculate the format for CONST_DOUBLE.  We need as many slots as
  85    are necessary to overlay a REAL_VALUE_TYPE on them.  This could be
  86    as many as four (32-bit HOST_WIDE_INT, 128-bit REAL_VALUE_TYPE).
  87
  88    A number of places assume that there are always at least two 'w'
  89    slots in a CONST_DOUBLE, so we provide them even if one would suffice.  */
  90
  91 #if REAL_WIDTH == 1
  92 # define CONST_DOUBLE_FORMAT     "ww"
  93 #else
  94 # if REAL_WIDTH == 2
  95 #  define CONST_DOUBLE_FORMAT    "ww"
  96 # else
  97 #  if REAL_WIDTH == 3
  98 #   define CONST_DOUBLE_FORMAT   "www"
  99 #  else
 100 #   if REAL_WIDTH == 4
 101 #    define CONST_DOUBLE_FORMAT  "wwww"
 102 #   else
 103 #    if REAL_WIDTH == 5
 104 #     define CONST_DOUBLE_FORMAT "wwwww"
 105 #    else
 106 #     if REAL_WIDTH == 6
 107 #      define CONST_DOUBLE_FORMAT "wwwwww"
 108 #     else
 109        #error "REAL_WIDTH > 6 not supported"
 110 #     endif
 111 #    endif
 112 #   endif
 113 #  endif
 114 # endif
 115 #endif
 116
 117
 118 /* Describes the properties of the specific target format in use.  */
 119 struct real_format
 120 {
 121   /* Move to and from the target bytes.  */
 122   void (*encode) (const struct real_format *, long *,
 123                   const REAL_VALUE_TYPE *);
 124   void (*decode) (const struct real_format *, REAL_VALUE_TYPE *,
 125                   const long *);
 126
 127   /* The radix of the exponent and digits of the significand.  */
 128   int b;
 129
 130   /* Size of the significand in digits of radix B.  */
 131   int p;
 132
 133   /* Size of the significant of a NaN, in digits of radix B.  */
 134   int pnan;
 135
 136   /* The minimum negative integer, x, such that b**(x-1) is normalized.  */
 137   int emin;
 138
 139   /* The maximum integer, x, such that b**(x-1) is representable.  */
 140   int emax;
 141
 142   /* The bit position of the sign bit, for determining whether a value
 143      is positive/negative, or -1 for a complex encoding.  */
 144   int signbit_ro;
 145
 146   /* The bit position of the sign bit, for changing the sign of a number,
 147      or -1 for a complex encoding.  */
 148   int signbit_rw;
 149
 150   /* Default rounding mode for operations on this format.  */
 151   bool round_towards_zero;
 152
 153   /* Properties of the format.  */
 154   bool has_nans;
 155   bool has_inf;
 156   bool has_denorm;
 157   bool has_signed_zero;
 158   bool qnan_msb_set;
 159   bool canonical_nan_lsbs_set;
 160 };
 161
 162
 163 /* The target format used for each floating point mode.
 164    Float modes are followed by decimal float modes, with entries for
 165    float modes indexed by (MODE - first float mode), and entries for
 166    decimal float modes indexed by (MODE - first decimal float mode) +
 167    the number of float modes.  */
 168 extern const struct real_format *
 169   real_format_for_mode[MAX_MODE_FLOAT - MIN_MODE_FLOAT + 1
 170                        + MAX_MODE_DECIMAL_FLOAT - MIN_MODE_DECIMAL_FLOAT + 1];
 171
 172 #define REAL_MODE_FORMAT(MODE)                                          \
 173   (real_format_for_mode[DECIMAL_FLOAT_MODE_P (MODE)                     \
 174                         ? ((MODE - MIN_MODE_DECIMAL_FLOAT)              \
 175                            + (MAX_MODE_FLOAT - MIN_MODE_FLOAT + 1))     \
 176                         : (MODE - MIN_MODE_FLOAT)])
 177
 178 /* The following macro determines whether the floating point format is
 179    composite, i.e. may contain non-consecutive mantissa bits, in which
 180    case compile-time FP overflow may not model run-time overflow.  */
 181 #define REAL_MODE_FORMAT_COMPOSITE_P(MODE) \
 182         ((REAL_MODE_FORMAT(MODE))->pnan < (REAL_MODE_FORMAT (MODE))->p)
 183
 184 /* Declare functions in real.c.  */
 185
 186 /* Binary or unary arithmetic on tree_code.  */
 187 extern bool real_arithmetic (REAL_VALUE_TYPE *, int, const REAL_VALUE_TYPE *,
 188                              const REAL_VALUE_TYPE *);
 189
 190 /* Compare reals by tree_code.  */
 191 extern bool real_compare (int, const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 192
 193 /* Determine whether a floating-point value X is infinite.  */
 194 extern bool real_isinf (const REAL_VALUE_TYPE *);
 195
 196 /* Determine whether a floating-point value X is a NaN.  */
 197 extern bool real_isnan (const REAL_VALUE_TYPE *);
 198
 199 /* Determine whether a floating-point value X is finite.  */
 200 extern bool real_isfinite (const REAL_VALUE_TYPE *);
 201
 202 /* Determine whether a floating-point value X is negative.  */
 203 extern bool real_isneg (const REAL_VALUE_TYPE *);
 204
 205 /* Determine whether a floating-point value X is minus zero.  */
 206 extern bool real_isnegzero (const REAL_VALUE_TYPE *);
 207
 208 /* Compare two floating-point objects for bitwise identity.  */
 209 extern bool real_identical (const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 210
 211 /* Extend or truncate to a new mode.  */
 212 extern void real_convert (REAL_VALUE_TYPE *, enum machine_mode,
 213                           const REAL_VALUE_TYPE *);
 214
 215 /* Return true if truncating to NEW is exact.  */
 216 extern bool exact_real_truncate (enum machine_mode, const REAL_VALUE_TYPE *);
 217
 218 /* Render R as a decimal floating point constant.  */
 219 extern void real_to_decimal (char *, const REAL_VALUE_TYPE *, size_t,
 220                              size_t, int);
 221
 222 /* Render R as a decimal floating point constant, rounded so as to be
 223    parsed back to the same value when interpreted in mode MODE.  */
 224 extern void real_to_decimal_for_mode (char *, const REAL_VALUE_TYPE *, size_t,
 225                                       size_t, int, enum machine_mode);
 226
 227 /* Render R as a hexadecimal floating point constant.  */
 228 extern void real_to_hexadecimal (char *, const REAL_VALUE_TYPE *,
 229                                  size_t, size_t, int);
 230
 231 /* Render R as an integer.  */
 232 extern HOST_WIDE_INT real_to_integer (const REAL_VALUE_TYPE *);
 233 extern void real_to_integer2 (HOST_WIDE_INT *, HOST_WIDE_INT *,
 234                               const REAL_VALUE_TYPE *);
 235
 236 /* Initialize R from a decimal or hexadecimal string.  Return -1 if
 237    the value underflows, +1 if overflows, and 0 otherwise.  */
 238 extern int real_from_string (REAL_VALUE_TYPE *, const char *);
 239 /* Wrapper to allow different internal representation for decimal floats. */
 240 extern void real_from_string3 (REAL_VALUE_TYPE *, const char *, enum machine_mode);
 241
 242 /* Initialize R from an integer pair HIGH/LOW.  */
 243 extern void real_from_integer (REAL_VALUE_TYPE *, enum machine_mode,
 244                                unsigned HOST_WIDE_INT, HOST_WIDE_INT, int);
 245
 246 extern long real_to_target_fmt (long *, const REAL_VALUE_TYPE *,
 247                                 const struct real_format *);
 248 extern long real_to_target (long *, const REAL_VALUE_TYPE *, enum machine_mode);
 249
 250 extern void real_from_target_fmt (REAL_VALUE_TYPE *, const long *,
 251                                   const struct real_format *);
 252 extern void real_from_target (REAL_VALUE_TYPE *, const long *,
 253                               enum machine_mode);
 254
 255 extern void real_inf (REAL_VALUE_TYPE *);
 256
 257 extern bool real_nan (REAL_VALUE_TYPE *, const char *, int, enum machine_mode);
 258
 259 extern void real_maxval (REAL_VALUE_TYPE *, int, enum machine_mode);
 260
 261 extern void real_2expN (REAL_VALUE_TYPE *, int, enum machine_mode);
 262
 263 extern unsigned int real_hash (const REAL_VALUE_TYPE *);
 264
 265
 266 /* Target formats defined in real.c.  */
 267 extern const struct real_format ieee_single_format;
 268 extern const struct real_format mips_single_format;
 269 extern const struct real_format motorola_single_format;
 270 extern const struct real_format spu_single_format;
 271 extern const struct real_format ieee_double_format;
 272 extern const struct real_format mips_double_format;
 273 extern const struct real_format motorola_double_format;
 274 extern const struct real_format ieee_extended_motorola_format;
 275 extern const struct real_format ieee_extended_intel_96_format;
 276 extern const struct real_format ieee_extended_intel_96_round_53_format;
 277 extern const struct real_format ieee_extended_intel_128_format;
 278 extern const struct real_format ibm_extended_format;
 279 extern const struct real_format mips_extended_format;
 280 extern const struct real_format ieee_quad_format;
 281 extern const struct real_format mips_quad_format;
 282 extern const struct real_format vax_f_format;
 283 extern const struct real_format vax_d_format;
 284 extern const struct real_format vax_g_format;
 285 extern const struct real_format real_internal_format;
 286 extern const struct real_format decimal_single_format;
 287 extern const struct real_format decimal_double_format;
 288 extern const struct real_format decimal_quad_format;
 289
 290
 291 /* ====================================================================== */
 292 /* Crap.  */
 293
 294 #define REAL_ARITHMETIC(value, code, d1, d2) \
 295   real_arithmetic (&(value), code, &(d1), &(d2))
 296
 297 #define REAL_VALUES_IDENTICAL(x, y)     real_identical (&(x), &(y))
 298 #define REAL_VALUES_EQUAL(x, y)         real_compare (EQ_EXPR, &(x), &(y))
 299 #define REAL_VALUES_LESS(x, y)          real_compare (LT_EXPR, &(x), &(y))
 300
 301 /* Determine whether a floating-point value X is infinite.  */
 302 #define REAL_VALUE_ISINF(x)             real_isinf (&(x))
 303
 304 /* Determine whether a floating-point value X is a NaN.  */
 305 #define REAL_VALUE_ISNAN(x)             real_isnan (&(x))
 306
 307 /* Determine whether a floating-point value X is negative.  */
 308 #define REAL_VALUE_NEGATIVE(x)          real_isneg (&(x))
 309
 310 /* Determine whether a floating-point value X is minus zero.  */
 311 #define REAL_VALUE_MINUS_ZERO(x)        real_isnegzero (&(x))
 312
 313 /* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
 314 #define REAL_VALUE_TO_TARGET_LONG_DOUBLE(IN, OUT)                       \
 315   real_to_target (OUT, &(IN),                                           \
 316                   mode_for_size (LONG_DOUBLE_TYPE_SIZE, MODE_FLOAT, 0))
 317
 318 #define REAL_VALUE_TO_TARGET_DOUBLE(IN, OUT) \
 319   real_to_target (OUT, &(IN), mode_for_size (64, MODE_FLOAT, 0))
 320
 321 /* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
 322 #define REAL_VALUE_TO_TARGET_SINGLE(IN, OUT) \
 323   ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_FLOAT, 0)))
 324
 325 #define REAL_VALUE_FROM_INT(r, lo, hi, mode) \
 326   real_from_integer (&(r), mode, lo, hi, 0)
 327
 328 #define REAL_VALUE_FROM_UNSIGNED_INT(r, lo, hi, mode) \
 329   real_from_integer (&(r), mode, lo, hi, 1)
 330
 331 /* Real values to IEEE 754 decimal floats.  */
 332
 333 /* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
 334 #define REAL_VALUE_TO_TARGET_DECIMAL128(IN, OUT) \
 335   real_to_target (OUT, &(IN), mode_for_size (128, MODE_DECIMAL_FLOAT, 0))
 336
 337 #define REAL_VALUE_TO_TARGET_DECIMAL64(IN, OUT) \
 338   real_to_target (OUT, &(IN), mode_for_size (64, MODE_DECIMAL_FLOAT, 0))
 339
 340 /* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
 341 #define REAL_VALUE_TO_TARGET_DECIMAL32(IN, OUT) \
 342   ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_DECIMAL_FLOAT, 0)))
 343
 344 extern REAL_VALUE_TYPE real_value_truncate (enum machine_mode,
 345                                             REAL_VALUE_TYPE);
 346
 347 #define REAL_VALUE_TO_INT(plow, phigh, r) \
 348   real_to_integer2 (plow, phigh, &(r))
 349
 350 extern REAL_VALUE_TYPE real_arithmetic2 (int, const REAL_VALUE_TYPE *,
 351                                          const REAL_VALUE_TYPE *);
 352
 353 #define REAL_VALUE_NEGATE(X) \
 354   real_arithmetic2 (NEGATE_EXPR, &(X), NULL)
 355
 356 #define REAL_VALUE_ABS(X) \
 357   real_arithmetic2 (ABS_EXPR, &(X), NULL)
 358
 359 extern int significand_size (enum machine_mode);
 360
 361 extern REAL_VALUE_TYPE real_from_string2 (const char *, enum machine_mode);
 362
 363 #define REAL_VALUE_ATOF(s, m) \
 364   real_from_string2 (s, m)
 365
 366 #define CONST_DOUBLE_ATOF(s, m) \
 367   CONST_DOUBLE_FROM_REAL_VALUE (real_from_string2 (s, m), m)
 368
 369 #define REAL_VALUE_FIX(r) \
 370   real_to_integer (&(r))
 371
 372 /* ??? Not quite right.  */
 373 #define REAL_VALUE_UNSIGNED_FIX(r) \
 374   real_to_integer (&(r))
 375
 376 /* ??? These were added for Paranoia support.  */
 377
 378 /* Return floor log2(R).  */
 379 extern int real_exponent (const REAL_VALUE_TYPE *);
 380
 381 /* R = A * 2**EXP.  */
 382 extern void real_ldexp (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *, int);
 383
 384 /* **** End of software floating point emulator interface macros **** */
 385 \f
 386 /* Constant real values 0, 1, 2, -1 and 0.5.  */
 387
 388 extern REAL_VALUE_TYPE dconst0;
 389 extern REAL_VALUE_TYPE dconst1;
 390 extern REAL_VALUE_TYPE dconst2;
 391 extern REAL_VALUE_TYPE dconstm1;
 392 extern REAL_VALUE_TYPE dconsthalf;
 393
 394 /* Enumerate the special constant values we need. */
 395 enum real_value_const {
 396   rv_e,
 397   rv_third,
 398   rv_sqrt2,
 399   rv_max
 400 };
 401
 402 /* Function to return a real value special constant.  */
 403 extern const REAL_VALUE_TYPE * get_real_const (enum real_value_const);
 404
 405 /* Function to return a real value (not a tree node)
 406    from a given integer constant.  */
 407 REAL_VALUE_TYPE real_value_from_int_cst (const_tree, const_tree);
 408
 409 /* Given a CONST_DOUBLE in FROM, store into TO the value it represents.  */
 410 #define REAL_VALUE_FROM_CONST_DOUBLE(to, from) \
 411   ((to) = *CONST_DOUBLE_REAL_VALUE (from))
 412
 413 /* Return a CONST_DOUBLE with value R and mode M.  */
 414 #define CONST_DOUBLE_FROM_REAL_VALUE(r, m) \
 415   const_double_from_real_value (r, m)
 416 extern rtx const_double_from_real_value (REAL_VALUE_TYPE, enum machine_mode);
 417
 418 /* Replace R by 1/R in the given machine mode, if the result is exact.  */
 419 extern bool exact_real_inverse (enum machine_mode, REAL_VALUE_TYPE *);
 420
 421 /* In tree.c: wrap up a REAL_VALUE_TYPE in a tree node.  */
 422 extern tree build_real (tree, REAL_VALUE_TYPE);
 423
 424 /* Calculate R as the square root of X in the given machine mode.  */
 425 extern bool real_sqrt (REAL_VALUE_TYPE *, enum machine_mode,
 426                        const REAL_VALUE_TYPE *);
 427
 428 /* Calculate R as X raised to the integer exponent N in mode MODE.  */
 429 extern bool real_powi (REAL_VALUE_TYPE *, enum machine_mode,
 430                        const REAL_VALUE_TYPE *, HOST_WIDE_INT);
 431
 432 /* Standard round to integer value functions.  */
 433 extern void real_trunc (REAL_VALUE_TYPE *, enum machine_mode,
 434                         const REAL_VALUE_TYPE *);
 435 extern void real_floor (REAL_VALUE_TYPE *, enum machine_mode,
 436                         const REAL_VALUE_TYPE *);
 437 extern void real_ceil (REAL_VALUE_TYPE *, enum machine_mode,
 438                        const REAL_VALUE_TYPE *);
 439 extern void real_round (REAL_VALUE_TYPE *, enum machine_mode,
 440                         const REAL_VALUE_TYPE *);
 441
 442 /* Set the sign of R to the sign of X.  */
 443 extern void real_copysign (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 444
 445 #ifndef GENERATOR_FILE
 446 /* Convert between MPFR and REAL_VALUE_TYPE.  The caller is
 447    responsible for initializing and clearing the MPFR parameter.  */
 448
 449 extern void real_from_mpfr (REAL_VALUE_TYPE *, mpfr_srcptr, tree, mp_rnd_t);
 450 extern void mpfr_from_real (mpfr_ptr, const REAL_VALUE_TYPE *, mp_rnd_t);
 451 #endif
 452
 453 /* Check whether the real constant value given is an integer.  */
 454 extern bool real_isinteger (const REAL_VALUE_TYPE *c, enum machine_mode mode);
 455
 456 /* Write into BUF the maximum representable finite floating-point
 457    number, (1 - b**-p) * b**emax for a given FP format FMT as a hex
 458    float string.  BUF must be large enough to contain the result.  */
 459 extern void get_max_float (const struct real_format *, char *, size_t);
 460 #endif /* ! GCC_REAL_H */