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 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   ENUM_BITFIELD (real_value_class) class : 2;
  46   unsigned int sign : 1;
  47   unsigned int signalling : 1;
  48   unsigned int canonical : 1;
  49   signed int exp : EXP_BITS;
  50   unsigned long sig[SIGSZ];
  51 };
  52
  53 /* Various headers condition prototypes on #ifdef REAL_VALUE_TYPE, so it
  54    needs to be a macro.  We do need to continue to have a structure tag
  55    so that other headers can forward declare it.  */
  56 #define REAL_VALUE_TYPE struct real_value
  57
  58 /* We store a REAL_VALUE_TYPE into an rtx, and we do this by putting it in
  59    consecutive "w" slots.  Moreover, we've got to compute the number of "w"
  60    slots at preprocessor time, which means we can't use sizeof.  Guess.  */
  61
  62 #define REAL_VALUE_TYPE_SIZE (SIGNIFICAND_BITS + 32)
  63 #define REAL_WIDTH \
  64   (REAL_VALUE_TYPE_SIZE/HOST_BITS_PER_WIDE_INT \
  65    + (REAL_VALUE_TYPE_SIZE%HOST_BITS_PER_WIDE_INT ? 1 : 0)) /* round up */
  66
  67 /* Verify the guess.  */
  68 extern char test_real_width
  69   [sizeof(REAL_VALUE_TYPE) <= REAL_WIDTH*sizeof(HOST_WIDE_INT) ? 1 : -1];
  70
  71 /* Calculate the format for CONST_DOUBLE.  We need as many slots as
  72    are necessary to overlay a REAL_VALUE_TYPE on them.  This could be
  73    as many as four (32-bit HOST_WIDE_INT, 128-bit REAL_VALUE_TYPE).
  74
  75    A number of places assume that there are always at least two 'w'
  76    slots in a CONST_DOUBLE, so we provide them even if one would suffice.  */
  77
  78 #if REAL_WIDTH == 1
  79 # define CONST_DOUBLE_FORMAT     "ww"
  80 #else
  81 # if REAL_WIDTH == 2
  82 #  define CONST_DOUBLE_FORMAT    "ww"
  83 # else
  84 #  if REAL_WIDTH == 3
  85 #   define CONST_DOUBLE_FORMAT   "www"
  86 #  else
  87 #   if REAL_WIDTH == 4
  88 #    define CONST_DOUBLE_FORMAT  "wwww"
  89 #   else
  90 #    if REAL_WIDTH == 5
  91 #     define CONST_DOUBLE_FORMAT "wwwww"
  92 #    else
  93 #     if REAL_WIDTH == 6
  94 #      define CONST_DOUBLE_FORMAT "wwwwww"
  95 #     else
  96        #error "REAL_WIDTH > 6 not supported"
  97 #     endif
  98 #    endif
  99 #   endif
 100 #  endif
 101 # endif
 102 #endif
 103
 104
 105 /* Describes the properties of the specific target format in use.  */
 106 struct real_format
 107 {
 108   /* Move to and from the target bytes.  */
 109   void (*encode) (const struct real_format *, long *,
 110                   const REAL_VALUE_TYPE *);
 111   void (*decode) (const struct real_format *, REAL_VALUE_TYPE *,
 112                   const long *);
 113
 114   /* The radix of the exponent and digits of the significand.  */
 115   int b;
 116
 117   /* log2(b).  */
 118   int log2_b;
 119
 120   /* Size of the significand in digits of radix B.  */
 121   int p;
 122
 123   /* Size of the significant of a NaN, in digits of radix B.  */
 124   int pnan;
 125
 126   /* The minimum negative integer, x, such that b**(x-1) is normalized.  */
 127   int emin;
 128
 129   /* The maximum integer, x, such that b**(x-1) is representable.  */
 130   int emax;
 131
 132   /* The bit position of the sign bit, or -1 for a complex encoding.  */
 133   int signbit;
 134
 135   /* Properties of the format.  */
 136   bool has_nans;
 137   bool has_inf;
 138   bool has_denorm;
 139   bool has_signed_zero;
 140   bool qnan_msb_set;
 141 };
 142
 143
 144 /* The target format used for each floating floating point mode.
 145    Indexed by MODE - QFmode.  */
 146 extern const struct real_format *real_format_for_mode[TFmode - QFmode + 1];
 147
 148
 149 /* Declare functions in real.c.  */
 150
 151 /* Binary or unary arithmetic on tree_code.  */
 152 extern void real_arithmetic (REAL_VALUE_TYPE *, int, const REAL_VALUE_TYPE *,
 153                              const REAL_VALUE_TYPE *);
 154
 155 /* Compare reals by tree_code.  */
 156 extern bool real_compare (int, const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 157
 158 /* Determine whether a floating-point value X is infinite.  */
 159 extern bool real_isinf (const REAL_VALUE_TYPE *);
 160
 161 /* Determine whether a floating-point value X is a NaN.  */
 162 extern bool real_isnan (const REAL_VALUE_TYPE *);
 163
 164 /* Determine whether a floating-point value X is negative.  */
 165 extern bool real_isneg (const REAL_VALUE_TYPE *);
 166
 167 /* Determine whether a floating-point value X is minus zero.  */
 168 extern bool real_isnegzero (const REAL_VALUE_TYPE *);
 169
 170 /* Compare two floating-point objects for bitwise identity.  */
 171 extern bool real_identical (const REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *);
 172
 173 /* Extend or truncate to a new mode.  */
 174 extern void real_convert (REAL_VALUE_TYPE *, enum machine_mode,
 175                           const REAL_VALUE_TYPE *);
 176
 177 /* Return true if truncating to NEW is exact.  */
 178 extern bool exact_real_truncate (enum machine_mode, const REAL_VALUE_TYPE *);
 179
 180 /* Render R as a decimal floating point constant.  */
 181 extern void real_to_decimal (char *, const REAL_VALUE_TYPE *, size_t,
 182                              size_t, int);
 183
 184 /* Render R as a hexadecimal floating point constant.  */
 185 extern void real_to_hexadecimal (char *, const REAL_VALUE_TYPE *,
 186                                  size_t, size_t, int);
 187
 188 /* Render R as an integer.  */
 189 extern HOST_WIDE_INT real_to_integer (const REAL_VALUE_TYPE *);
 190 extern void real_to_integer2 (HOST_WIDE_INT *, HOST_WIDE_INT *,
 191                               const REAL_VALUE_TYPE *);
 192
 193 /* Initialize R from a decimal or hexadecimal string.  */
 194 extern void real_from_string (REAL_VALUE_TYPE *, const char *);
 195
 196 /* Initialize R from an integer pair HIGH/LOW.  */
 197 extern void real_from_integer (REAL_VALUE_TYPE *, enum machine_mode,
 198                                unsigned HOST_WIDE_INT, HOST_WIDE_INT, int);
 199
 200 extern long real_to_target_fmt (long *, const REAL_VALUE_TYPE *,
 201                                 const struct real_format *);
 202 extern long real_to_target (long *, const REAL_VALUE_TYPE *, enum machine_mode);
 203
 204 extern void real_from_target_fmt (REAL_VALUE_TYPE *, const long *,
 205                                   const struct real_format *);
 206 extern void real_from_target (REAL_VALUE_TYPE *, const long *,
 207                               enum machine_mode);
 208
 209 extern void real_inf (REAL_VALUE_TYPE *);
 210
 211 extern bool real_nan (REAL_VALUE_TYPE *, const char *, int, enum machine_mode);
 212
 213 extern void real_maxval (REAL_VALUE_TYPE *, int, enum machine_mode);
 214
 215 extern void real_2expN (REAL_VALUE_TYPE *, int);
 216
 217 extern unsigned int real_hash (const REAL_VALUE_TYPE *);
 218
 219
 220 /* Target formats defined in real.c.  */
 221 extern const struct real_format ieee_single_format;
 222 extern const struct real_format mips_single_format;
 223 extern const struct real_format ieee_double_format;
 224 extern const struct real_format mips_double_format;
 225 extern const struct real_format ieee_extended_motorola_format;
 226 extern const struct real_format ieee_extended_intel_96_format;
 227 extern const struct real_format ieee_extended_intel_96_round_53_format;
 228 extern const struct real_format ieee_extended_intel_128_format;
 229 extern const struct real_format ibm_extended_format;
 230 extern const struct real_format mips_extended_format;
 231 extern const struct real_format ieee_quad_format;
 232 extern const struct real_format mips_quad_format;
 233 extern const struct real_format vax_f_format;
 234 extern const struct real_format vax_d_format;
 235 extern const struct real_format vax_g_format;
 236 extern const struct real_format i370_single_format;
 237 extern const struct real_format i370_double_format;
 238 extern const struct real_format c4x_single_format;
 239 extern const struct real_format c4x_extended_format;
 240 extern const struct real_format real_internal_format;
 241
 242
 243 /* ====================================================================== */
 244 /* Crap.  */
 245
 246 #define REAL_ARITHMETIC(value, code, d1, d2) \
 247   real_arithmetic (&(value), code, &(d1), &(d2))
 248
 249 #define REAL_VALUES_IDENTICAL(x, y)     real_identical (&(x), &(y))
 250 #define REAL_VALUES_EQUAL(x, y)         real_compare (EQ_EXPR, &(x), &(y))
 251 #define REAL_VALUES_LESS(x, y)          real_compare (LT_EXPR, &(x), &(y))
 252
 253 /* Determine whether a floating-point value X is infinite.  */
 254 #define REAL_VALUE_ISINF(x)             real_isinf (&(x))
 255
 256 /* Determine whether a floating-point value X is a NaN.  */
 257 #define REAL_VALUE_ISNAN(x)             real_isnan (&(x))
 258
 259 /* Determine whether a floating-point value X is negative.  */
 260 #define REAL_VALUE_NEGATIVE(x)          real_isneg (&(x))
 261
 262 /* Determine whether a floating-point value X is minus zero.  */
 263 #define REAL_VALUE_MINUS_ZERO(x)        real_isnegzero (&(x))
 264
 265 /* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
 266 #define REAL_VALUE_TO_TARGET_LONG_DOUBLE(IN, OUT)                       \
 267   real_to_target (OUT, &(IN),                                           \
 268                   mode_for_size (LONG_DOUBLE_TYPE_SIZE, MODE_FLOAT, 0))
 269
 270 #define REAL_VALUE_TO_TARGET_DOUBLE(IN, OUT) \
 271   real_to_target (OUT, &(IN), mode_for_size (64, MODE_FLOAT, 0))
 272
 273 /* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
 274 #define REAL_VALUE_TO_TARGET_SINGLE(IN, OUT) \
 275   ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_FLOAT, 0)))
 276
 277 #define REAL_VALUE_FROM_INT(r, lo, hi, mode) \
 278   real_from_integer (&(r), mode, lo, hi, 0)
 279
 280 #define REAL_VALUE_FROM_UNSIGNED_INT(r, lo, hi, mode) \
 281   real_from_integer (&(r), mode, lo, hi, 1)
 282
 283 extern REAL_VALUE_TYPE real_value_truncate (enum machine_mode,
 284                                             REAL_VALUE_TYPE);
 285
 286 #define REAL_VALUE_TO_INT(plow, phigh, r) \
 287   real_to_integer2 (plow, phigh, &(r))
 288
 289 extern REAL_VALUE_TYPE real_arithmetic2 (int, const REAL_VALUE_TYPE *,
 290                                          const REAL_VALUE_TYPE *);
 291
 292 #define REAL_VALUE_NEGATE(X) \
 293   real_arithmetic2 (NEGATE_EXPR, &(X), NULL)
 294
 295 #define REAL_VALUE_ABS(X) \
 296   real_arithmetic2 (ABS_EXPR, &(X), NULL)
 297
 298 extern int significand_size (enum machine_mode);
 299
 300 extern REAL_VALUE_TYPE real_from_string2 (const char *, enum machine_mode);
 301
 302 #define REAL_VALUE_ATOF(s, m) \
 303   real_from_string2 (s, m)
 304
 305 #define CONST_DOUBLE_ATOF(s, m) \
 306   CONST_DOUBLE_FROM_REAL_VALUE (real_from_string2 (s, m), m)
 307
 308 #define REAL_VALUE_FIX(r) \
 309   real_to_integer (&(r))
 310
 311 /* ??? Not quite right.  */
 312 #define REAL_VALUE_UNSIGNED_FIX(r) \
 313   real_to_integer (&(r))
 314
 315 /* ??? These were added for Paranoia support.  */
 316
 317 /* Return floor log2(R).  */
 318 extern int real_exponent (const REAL_VALUE_TYPE *);
 319
 320 /* R = A * 2**EXP.  */
 321 extern void real_ldexp (REAL_VALUE_TYPE *, const REAL_VALUE_TYPE *, int);
 322
 323 /* **** End of software floating point emulator interface macros **** */
 324 \f
 325 /* Constant real values 0, 1, 2, -1, -2 and 0.5.  */
 326
 327 extern REAL_VALUE_TYPE dconst0;
 328 extern REAL_VALUE_TYPE dconst1;
 329 extern REAL_VALUE_TYPE dconst2;
 330 extern REAL_VALUE_TYPE dconstm1;
 331 extern REAL_VALUE_TYPE dconstm2;
 332 extern REAL_VALUE_TYPE dconsthalf;
 333
 334 /* Function to return a real value (not a tree node)
 335    from a given integer constant.  */
 336 REAL_VALUE_TYPE real_value_from_int_cst (tree, tree);
 337
 338 /* Given a CONST_DOUBLE in FROM, store into TO the value it represents.  */
 339 #define REAL_VALUE_FROM_CONST_DOUBLE(to, from) \
 340   memcpy (&(to), &CONST_DOUBLE_LOW ((from)), sizeof (REAL_VALUE_TYPE))
 341
 342 /* Return a CONST_DOUBLE with value R and mode M.  */
 343 #define CONST_DOUBLE_FROM_REAL_VALUE(r, m) \
 344   const_double_from_real_value (r, m)
 345 extern rtx const_double_from_real_value (REAL_VALUE_TYPE, enum machine_mode);
 346
 347 /* Replace R by 1/R in the given machine mode, if the result is exact.  */
 348 extern bool exact_real_inverse (enum machine_mode, REAL_VALUE_TYPE *);
 349
 350 /* In tree.c: wrap up a REAL_VALUE_TYPE in a tree node.  */
 351 extern tree build_real (tree, REAL_VALUE_TYPE);
 352
 353 /* Calculate R as the square root of X in the given machine mode.  */
 354 extern bool real_sqrt (REAL_VALUE_TYPE *, enum machine_mode,
 355                        const REAL_VALUE_TYPE *);
 356
 357 /* Calculate R as X raised to the integer exponent N in mode MODE.  */
 358 extern bool real_powi (REAL_VALUE_TYPE *, enum machine_mode,
 359                        const REAL_VALUE_TYPE *, HOST_WIDE_INT);
 360
 361 /* Standard round to integer value functions.  */
 362 extern void real_trunc (REAL_VALUE_TYPE *, enum machine_mode,
 363                         const REAL_VALUE_TYPE *);
 364 extern void real_floor (REAL_VALUE_TYPE *, enum machine_mode,
 365                         const REAL_VALUE_TYPE *);
 366 extern void real_ceil (REAL_VALUE_TYPE *, enum machine_mode,
 367                        const REAL_VALUE_TYPE *);
 368
 369 #endif /* ! GCC_REAL_H */