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, 59 Temple Place - Suite 330, Boston, MA
  20    02111-1307, USA.  */
  21
  22 #ifndef GCC_REAL_H
  23 #define GCC_REAL_H
  24
  25 #include "machmode.h"
  26
  27 /* An expanded form of the represented number.  */
  28
  29 /* Enumerate the special cases of numbers that we encounter.  */
  30 enum real_value_class {
  31   rvc_zero,
  32   rvc_normal,
  33   rvc_inf,
  34   rvc_nan
  35 };
  36
  37 #define SIGNIFICAND_BITS        (128 + HOST_BITS_PER_LONG)
  38 #define EXP_BITS                (32 - 5)
  39 #define MAX_EXP                 ((1 << (EXP_BITS - 1)) - 1)
  40 #define SIGSZ                   (SIGNIFICAND_BITS / HOST_BITS_PER_LONG)
  41 #define SIG_MSB                 ((unsigned long)1 << (HOST_BITS_PER_LONG - 1))
  42
  43 struct real_value GTY(())
  44 {
  45   /* Use the same underlying type for all bit-fields, so as to make
  46      sure they're packed together, otherwise REAL_VALUE_TYPE_SIZE will
  47      be miscomputed.  */
  48   unsigned int /* ENUM_BITFIELD (real_value_class) */ cl : 2;
  49   unsigned int sign : 1;
  50   unsigned int signalling : 1;
  51   unsigned int canonical : 1;
  52   unsigned int uexp : EXP_BITS;
  53   unsigned long sig[SIGSZ];
  54 };
  55
  56 #define REAL_EXP(REAL) \
  57   ((int)((REAL)->uexp ^ (unsigned int)(1 << (EXP_BITS - 1))) \
  58    - (1 << (EXP_BITS - 1)))
  59 #define SET_REAL_EXP(REAL, EXP) \
  60   ((REAL)->uexp = ((unsigned int)(EXP) & (unsigned int)((1 << EXP_BITS) - 1)))
  61
  62 /* Various headers condition prototypes on #ifdef REAL_VALUE_TYPE, so it
  63    needs to be a macro.  We do need to continue to have a structure tag
  64    so that other headers can forward declare it.  */
  65 #define REAL_VALUE_TYPE struct real_value
  66
  67 /* We store a REAL_VALUE_TYPE into an rtx, and we do this by putting it in
  68    consecutive "w" slots.  Moreover, we've got to compute the number of "w"
  69    slots at preprocessor time, which means we can't use sizeof.  Guess.  */
  70
  71 #define REAL_VALUE_TYPE_SIZE (SIGNIFICAND_BITS + 32)
  72 #define REAL_WIDTH \
  73   (REAL_VALUE_TYPE_SIZE/HOST_BITS_PER_WIDE_INT \
  74    + (REAL_VALUE_TYPE_SIZE%HOST_BITS_PER_WIDE_INT ? 1 : 0)) /* round up */
  75
  76 /* Verify the guess.  */
  77 extern char test_real_width
  78   [sizeof(REAL_VALUE_TYPE) <= REAL_WIDTH*sizeof(HOST_WIDE_INT) ? 1 : -1];
  79
  80 /* Calculate the format for CONST_DOUBLE.  We need as many slots as
  81    are necessary to overlay a REAL_VALUE_TYPE on them.  This could be
  82    as many as four (32-bit HOST_WIDE_INT, 128-bit REAL_VALUE_TYPE).
  83
  84    A number of places assume that there are always at least two 'w'
  85    slots in a CONST_DOUBLE, so we provide them even if one would suffice.  */
  86
  87 #if REAL_WIDTH == 1
  88 # define CONST_DOUBLE_FORMAT     "ww"
  89 #else
  90 # if REAL_WIDTH == 2
  91 #  define CONST_DOUBLE_FORMAT    "ww"
  92 # else
  93 #  if REAL_WIDTH == 3
  94 #   define CONST_DOUBLE_FORMAT   "www"
  95 #  else
  96 #   if REAL_WIDTH == 4
  97 #    define CONST_DOUBLE_FORMAT  "wwww"
  98 #   else
  99 #    if REAL_WIDTH == 5
 100 #     define CONST_DOUBLE_FORMAT "wwwww"
 101 #    else
 102 #     if REAL_WIDTH == 6
 103 #      define CONST_DOUBLE_FORMAT "wwwwww"
 104 #     else
 105        #error "REAL_WIDTH > 6 not supported"
 106 #     endif
 107 #    endif
 108 #   endif
 109 #  endif
 110 # endif
 111 #endif
 112
 113
 114 /* Describes the properties of the specific target format in use.  */
 115 struct real_format
 116 {
 117   /* Move to and from the target bytes.  */
 118   void (*encode) (const struct real_format *, long *,
 119                   const REAL_VALUE_TYPE *);
 120   void (*decode) (const struct real_format *, REAL_VALUE_TYPE *,
 121                   const long *);
 122
 123   /* The radix of the exponent and digits of the significand.  */
 124   int b;
 125
 126   /* log2(b).  */
 127   int log2_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, or -1 for a complex encoding.  */
 142   int signbit;
 143
 144   /* Properties of the format.  */
 145   bool has_nans;
 146   bool has_inf;
 147   bool has_denorm;
 148   bool has_signed_zero;
 149   bool qnan_msb_set;
 150 };
 151
 152
 153 /* The target format used for each floating floating point mode.
 154    Indexed by MODE - QFmode.  */
 155 extern const struct real_format *
 156   real_format_for_mode[MAX_MODE_FLOAT - MIN_MODE_FLOAT + 1];
 157
 158 #define REAL_MODE_FORMAT(MODE) (real_format_for_mode[(MODE) - MIN_MODE_FLOAT])
 159
 160 /* Declare functions in real.c.  */
 161
 162 /* Binary or unary arithmetic on tree_code.  */
 163 extern bool real_arithmetic (REAL_VALUE_TYPE *, int, const REAL_VALUE_TYPE *,
 164                              const REAL_VALUE_TYPE *);
 165
 166 /* Compare reals by tree_code.  */
 167 extern bool real_compare (int, const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 168
 169 /* Determine whether a floating-point value X is infinite.  */
 170 extern bool real_isinf (const REAL_VALUE_TYPE *);
 171
 172 /* Determine whether a floating-point value X is a NaN.  */
 173 extern bool real_isnan (const REAL_VALUE_TYPE *);
 174
 175 /* Determine whether a floating-point value X is negative.  */
 176 extern bool real_isneg (const REAL_VALUE_TYPE *);
 177
 178 /* Determine whether a floating-point value X is minus zero.  */
 179 extern bool real_isnegzero (const REAL_VALUE_TYPE *);
 180
 181 /* Compare two floating-point objects for bitwise identity.  */
 182 extern bool real_identical (const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 183
 184 /* Extend or truncate to a new mode.  */
 185 extern void real_convert (REAL_VALUE_TYPE *, enum machine_mode,
 186                           const REAL_VALUE_TYPE *);
 187
 188 /* Return true if truncating to NEW is exact.  */
 189 extern bool exact_real_truncate (enum machine_mode, const REAL_VALUE_TYPE *);
 190
 191 /* Render R as a decimal floating point constant.  */
 192 extern void real_to_decimal (char *, const REAL_VALUE_TYPE *, size_t,
 193                              size_t, int);
 194
 195 /* Render R as a hexadecimal floating point constant.  */
 196 extern void real_to_hexadecimal (char *, const REAL_VALUE_TYPE *,
 197                                  size_t, size_t, int);
 198
 199 /* Render R as an integer.  */
 200 extern HOST_WIDE_INT real_to_integer (const REAL_VALUE_TYPE *);
 201 extern void real_to_integer2 (HOST_WIDE_INT *, HOST_WIDE_INT *,
 202                               const REAL_VALUE_TYPE *);
 203
 204 /* Initialize R from a decimal or hexadecimal string.  */
 205 extern void real_from_string (REAL_VALUE_TYPE *, const char *);
 206
 207 /* Initialize R from an integer pair HIGH/LOW.  */
 208 extern void real_from_integer (REAL_VALUE_TYPE *, enum machine_mode,
 209                                unsigned HOST_WIDE_INT, HOST_WIDE_INT, int);
 210
 211 extern long real_to_target_fmt (long *, const REAL_VALUE_TYPE *,
 212                                 const struct real_format *);
 213 extern long real_to_target (long *, const REAL_VALUE_TYPE *, enum machine_mode);
 214
 215 extern void real_from_target_fmt (REAL_VALUE_TYPE *, const long *,
 216                                   const struct real_format *);
 217 extern void real_from_target (REAL_VALUE_TYPE *, const long *,
 218                               enum machine_mode);
 219
 220 extern void real_inf (REAL_VALUE_TYPE *);
 221
 222 extern bool real_nan (REAL_VALUE_TYPE *, const char *, int, enum machine_mode);
 223
 224 extern void real_maxval (REAL_VALUE_TYPE *, int, enum machine_mode);
 225
 226 extern void real_2expN (REAL_VALUE_TYPE *, int);
 227
 228 extern unsigned int real_hash (const REAL_VALUE_TYPE *);
 229
 230
 231 /* Target formats defined in real.c.  */
 232 extern const struct real_format ieee_single_format;
 233 extern const struct real_format mips_single_format;
 234 extern const struct real_format ieee_double_format;
 235 extern const struct real_format mips_double_format;
 236 extern const struct real_format ieee_extended_motorola_format;
 237 extern const struct real_format ieee_extended_intel_96_format;
 238 extern const struct real_format ieee_extended_intel_96_round_53_format;
 239 extern const struct real_format ieee_extended_intel_128_format;
 240 extern const struct real_format ibm_extended_format;
 241 extern const struct real_format mips_extended_format;
 242 extern const struct real_format ieee_quad_format;
 243 extern const struct real_format mips_quad_format;
 244 extern const struct real_format vax_f_format;
 245 extern const struct real_format vax_d_format;
 246 extern const struct real_format vax_g_format;
 247 extern const struct real_format i370_single_format;
 248 extern const struct real_format i370_double_format;
 249 extern const struct real_format c4x_single_format;
 250 extern const struct real_format c4x_extended_format;
 251 extern const struct real_format real_internal_format;
 252
 253
 254 /* ====================================================================== */
 255 /* Crap.  */
 256
 257 #define REAL_ARITHMETIC(value, code, d1, d2) \
 258   real_arithmetic (&(value), code, &(d1), &(d2))
 259
 260 #define REAL_VALUES_IDENTICAL(x, y)     real_identical (&(x), &(y))
 261 #define REAL_VALUES_EQUAL(x, y)         real_compare (EQ_EXPR, &(x), &(y))
 262 #define REAL_VALUES_LESS(x, y)          real_compare (LT_EXPR, &(x), &(y))
 263
 264 /* Determine whether a floating-point value X is infinite.  */
 265 #define REAL_VALUE_ISINF(x)             real_isinf (&(x))
 266
 267 /* Determine whether a floating-point value X is a NaN.  */
 268 #define REAL_VALUE_ISNAN(x)             real_isnan (&(x))
 269
 270 /* Determine whether a floating-point value X is negative.  */
 271 #define REAL_VALUE_NEGATIVE(x)          real_isneg (&(x))
 272
 273 /* Determine whether a floating-point value X is minus zero.  */
 274 #define REAL_VALUE_MINUS_ZERO(x)        real_isnegzero (&(x))
 275
 276 /* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
 277 #define REAL_VALUE_TO_TARGET_LONG_DOUBLE(IN, OUT)                       \
 278   real_to_target (OUT, &(IN),                                           \
 279                   mode_for_size (LONG_DOUBLE_TYPE_SIZE, MODE_FLOAT, 0))
 280
 281 #define REAL_VALUE_TO_TARGET_DOUBLE(IN, OUT) \
 282   real_to_target (OUT, &(IN), mode_for_size (64, MODE_FLOAT, 0))
 283
 284 /* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
 285 #define REAL_VALUE_TO_TARGET_SINGLE(IN, OUT) \
 286   ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_FLOAT, 0)))
 287
 288 #define REAL_VALUE_FROM_INT(r, lo, hi, mode) \
 289   real_from_integer (&(r), mode, lo, hi, 0)
 290
 291 #define REAL_VALUE_FROM_UNSIGNED_INT(r, lo, hi, mode) \
 292   real_from_integer (&(r), mode, lo, hi, 1)
 293
 294 extern REAL_VALUE_TYPE real_value_truncate (enum machine_mode,
 295                                             REAL_VALUE_TYPE);
 296
 297 #define REAL_VALUE_TO_INT(plow, phigh, r) \
 298   real_to_integer2 (plow, phigh, &(r))
 299
 300 extern REAL_VALUE_TYPE real_arithmetic2 (int, const REAL_VALUE_TYPE *,
 301                                          const REAL_VALUE_TYPE *);
 302
 303 #define REAL_VALUE_NEGATE(X) \
 304   real_arithmetic2 (NEGATE_EXPR, &(X), NULL)
 305
 306 #define REAL_VALUE_ABS(X) \
 307   real_arithmetic2 (ABS_EXPR, &(X), NULL)
 308
 309 extern int significand_size (enum machine_mode);
 310
 311 extern REAL_VALUE_TYPE real_from_string2 (const char *, enum machine_mode);
 312
 313 #define REAL_VALUE_ATOF(s, m) \
 314   real_from_string2 (s, m)
 315
 316 #define CONST_DOUBLE_ATOF(s, m) \
 317   CONST_DOUBLE_FROM_REAL_VALUE (real_from_string2 (s, m), m)
 318
 319 #define REAL_VALUE_FIX(r) \
 320   real_to_integer (&(r))
 321
 322 /* ??? Not quite right.  */
 323 #define REAL_VALUE_UNSIGNED_FIX(r) \
 324   real_to_integer (&(r))
 325
 326 /* ??? These were added for Paranoia support.  */
 327
 328 /* Return floor log2(R).  */
 329 extern int real_exponent (const REAL_VALUE_TYPE *);
 330
 331 /* R = A * 2**EXP.  */
 332 extern void real_ldexp (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *, int);
 333
 334 /* **** End of software floating point emulator interface macros **** */
 335 \f
 336 /* Constant real values 0, 1, 2, 3, 10, -1, -2, 0.5 and 1/3.  */
 337
 338 extern REAL_VALUE_TYPE dconst0;
 339 extern REAL_VALUE_TYPE dconst1;
 340 extern REAL_VALUE_TYPE dconst2;
 341 extern REAL_VALUE_TYPE dconst3;
 342 extern REAL_VALUE_TYPE dconst10;
 343 extern REAL_VALUE_TYPE dconstm1;
 344 extern REAL_VALUE_TYPE dconstm2;
 345 extern REAL_VALUE_TYPE dconsthalf;
 346 extern REAL_VALUE_TYPE dconstthird;
 347 extern REAL_VALUE_TYPE dconstpi;
 348 extern REAL_VALUE_TYPE dconste;
 349
 350 /* Function to return a real value (not a tree node)
 351    from a given integer constant.  */
 352 REAL_VALUE_TYPE real_value_from_int_cst (tree, tree);
 353
 354 /* Given a CONST_DOUBLE in FROM, store into TO the value it represents.  */
 355 #define REAL_VALUE_FROM_CONST_DOUBLE(to, from) \
 356   memcpy (&(to), &CONST_DOUBLE_LOW ((from)), sizeof (REAL_VALUE_TYPE))
 357
 358 /* Return a CONST_DOUBLE with value R and mode M.  */
 359 #define CONST_DOUBLE_FROM_REAL_VALUE(r, m) \
 360   const_double_from_real_value (r, m)
 361 extern rtx const_double_from_real_value (REAL_VALUE_TYPE, enum machine_mode);
 362
 363 /* Replace R by 1/R in the given machine mode, if the result is exact.  */
 364 extern bool exact_real_inverse (enum machine_mode, REAL_VALUE_TYPE *);
 365
 366 /* In tree.c: wrap up a REAL_VALUE_TYPE in a tree node.  */
 367 extern tree build_real (tree, REAL_VALUE_TYPE);
 368
 369 /* Calculate R as the square root of X in the given machine mode.  */
 370 extern bool real_sqrt (REAL_VALUE_TYPE *, enum machine_mode,
 371                        const REAL_VALUE_TYPE *);
 372
 373 /* Calculate R as X raised to the integer exponent N in mode MODE.  */
 374 extern bool real_powi (REAL_VALUE_TYPE *, enum machine_mode,
 375                        const REAL_VALUE_TYPE *, HOST_WIDE_INT);
 376
 377 /* Standard round to integer value functions.  */
 378 extern void real_trunc (REAL_VALUE_TYPE *, enum machine_mode,
 379                         const REAL_VALUE_TYPE *);
 380 extern void real_floor (REAL_VALUE_TYPE *, enum machine_mode,
 381                         const REAL_VALUE_TYPE *);
 382 extern void real_ceil (REAL_VALUE_TYPE *, enum machine_mode,
 383                        const REAL_VALUE_TYPE *);
 384 extern void real_round (REAL_VALUE_TYPE *, enum machine_mode,
 385                         const REAL_VALUE_TYPE *);
 386
 387 /* Set the sign of R to the sign of X.  */
 388 extern void real_copysign (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 389
 390 #endif /* ! GCC_REAL_H */