gcc/real.h

   1 /* Definitions of floating-point access for GNU compiler.
   2    Copyright (C) 1989, 1991, 1994, 1996, 1997, 1998,
   3    1999, 2000, 2002 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 - 3)
  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   signed int exp : EXP_BITS;
  48   unsigned long sig[SIGSZ];
  49 };
  50
  51 /* Various headers condition prototypes on #ifdef REAL_VALUE_TYPE, so it
  52    needs to be a macro.  We do need to continue to have a structure tag
  53    so that other headers can forward declare it.  */
  54 #define REAL_VALUE_TYPE struct real_value
  55
  56 /* We store a REAL_VALUE_TYPE into an rtx, and we do this by putting it in
  57    consecutive "w" slots.  Moreover, we've got to compute the number of "w"
  58    slots at preprocessor time, which means we can't use sizeof.  Guess.  */
  59
  60 #define REAL_VALUE_TYPE_SIZE (SIGNIFICAND_BITS + 32)
  61 #define REAL_WIDTH \
  62   (REAL_VALUE_TYPE_SIZE/HOST_BITS_PER_WIDE_INT \
  63    + (REAL_VALUE_TYPE_SIZE%HOST_BITS_PER_WIDE_INT ? 1 : 0)) /* round up */
  64
  65 /* Verify the guess.  */
  66 extern char test_real_width
  67   [sizeof(REAL_VALUE_TYPE) <= REAL_WIDTH*sizeof(HOST_WIDE_INT) ? 1 : -1];
  68
  69 /* Calculate the format for CONST_DOUBLE.  We need as many slots as
  70    are necessary to overlay a REAL_VALUE_TYPE on them.  This could be
  71    as many as four (32-bit HOST_WIDE_INT, 128-bit REAL_VALUE_TYPE).
  72
  73    A number of places assume that there are always at least two 'w'
  74    slots in a CONST_DOUBLE, so we provide them even if one would suffice.  */
  75
  76 #if REAL_WIDTH == 1
  77 # define CONST_DOUBLE_FORMAT     "ww"
  78 #else
  79 # if REAL_WIDTH == 2
  80 #  define CONST_DOUBLE_FORMAT    "ww"
  81 # else
  82 #  if REAL_WIDTH == 3
  83 #   define CONST_DOUBLE_FORMAT   "www"
  84 #  else
  85 #   if REAL_WIDTH == 4
  86 #    define CONST_DOUBLE_FORMAT  "wwww"
  87 #   else
  88 #    if REAL_WIDTH == 5
  89 #     define CONST_DOUBLE_FORMAT "wwwww"
  90 #    else
  91 #     if REAL_WIDTH == 6
  92 #      define CONST_DOUBLE_FORMAT "wwwwww"
  93 #     else
  94        #error "REAL_WIDTH > 6 not supported"
  95 #     endif
  96 #    endif
  97 #   endif
  98 #  endif
  99 # endif
 100 #endif
 101
 102
 103 /* Describes the properties of the specific target format in use.  */
 104 struct real_format
 105 {
 106   /* Move to and from the target bytes.  */
 107   void (*encode) PARAMS ((const struct real_format *, long *,
 108                           const REAL_VALUE_TYPE *));
 109   void (*decode) PARAMS ((const struct real_format *, REAL_VALUE_TYPE *,
 110                           const long *));
 111
 112   /* The radix of the exponent and digits of the significand.  */
 113   int b;
 114
 115   /* log2(b).  */
 116   int log2_b;
 117
 118   /* Size of the significand in digits of radix B.  */
 119   int p;
 120
 121   /* The minimum negative integer, x, such that b**(x-1) is normalized.  */
 122   int emin;
 123
 124   /* The maximum integer, x, such that b**(x-1) is representable.  */
 125   int emax;
 126
 127   /* The bit position of the sign bit, or -1 for a complex encoding.  */
 128   int signbit;
 129
 130   /* Properties of the format.  */
 131   bool has_nans;
 132   bool has_inf;
 133   bool has_denorm;
 134   bool has_signed_zero;
 135   bool qnan_msb_set;
 136 };
 137
 138
 139 /* The target format used for each floating floating point mode.
 140    Indexed by MODE - QFmode.  */
 141 extern const struct real_format *real_format_for_mode[TFmode - QFmode + 1];
 142
 143
 144 /* Declare functions in real.c.  */
 145
 146 /* Binary or unary arithmetic on tree_code.  */
 147 extern void real_arithmetic     PARAMS ((REAL_VALUE_TYPE *, int,
 148                                          const REAL_VALUE_TYPE *,
 149                                          const REAL_VALUE_TYPE *));
 150
 151 /* Compare reals by tree_code.  */
 152 extern bool real_compare        PARAMS ((int, const REAL_VALUE_TYPE *,
 153                                          const REAL_VALUE_TYPE *));
 154
 155 /* Determine whether a floating-point value X is infinite.  */
 156 extern bool real_isinf          PARAMS ((const REAL_VALUE_TYPE *));
 157
 158 /* Determine whether a floating-point value X is a NaN.  */
 159 extern bool real_isnan          PARAMS ((const REAL_VALUE_TYPE *));
 160
 161 /* Determine whether a floating-point value X is negative.  */
 162 extern bool real_isneg          PARAMS ((const REAL_VALUE_TYPE *));
 163
 164 /* Determine whether a floating-point value X is minus zero.  */
 165 extern bool real_isnegzero      PARAMS ((const REAL_VALUE_TYPE *));
 166
 167 /* Compare two floating-point objects for bitwise identity.  */
 168 extern bool real_identical      PARAMS ((const REAL_VALUE_TYPE *,
 169                                          const REAL_VALUE_TYPE *));
 170
 171 /* Extend or truncate to a new mode.  */
 172 extern void real_convert        PARAMS ((REAL_VALUE_TYPE *,
 173                                          enum machine_mode,
 174                                          const REAL_VALUE_TYPE *));
 175
 176 /* Return true if truncating to NEW is exact.  */
 177 extern bool exact_real_truncate PARAMS ((enum machine_mode,
 178                                          const REAL_VALUE_TYPE *));
 179
 180 /* Render R as a decimal floating point constant.  */
 181 extern void real_to_decimal     PARAMS ((char *, const REAL_VALUE_TYPE *,
 182                                          size_t, size_t, int));
 183
 184 /* Render R as a hexadecimal floating point constant.  */
 185 extern void real_to_hexadecimal PARAMS ((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 PARAMS ((const REAL_VALUE_TYPE *));
 190 extern void real_to_integer2 PARAMS ((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    PARAMS ((REAL_VALUE_TYPE *, const char *));
 195
 196 /* Initialize R from an integer pair HIGH/LOW.  */
 197 extern void real_from_integer   PARAMS ((REAL_VALUE_TYPE *,
 198                                          enum machine_mode,
 199                                          unsigned HOST_WIDE_INT,
 200                                          HOST_WIDE_INT, int));
 201
 202 extern long real_to_target_fmt  PARAMS ((long *, const REAL_VALUE_TYPE *,
 203                                          const struct real_format *));
 204 extern long real_to_target      PARAMS ((long *, const REAL_VALUE_TYPE *,
 205                                          enum machine_mode));
 206
 207 extern void real_from_target_fmt PARAMS ((REAL_VALUE_TYPE *, const long *,
 208                                           const struct real_format *));
 209 extern void real_from_target    PARAMS ((REAL_VALUE_TYPE *, const long *,
 210                                          enum machine_mode));
 211
 212 extern void real_inf            PARAMS ((REAL_VALUE_TYPE *));
 213
 214 extern bool real_nan            PARAMS ((REAL_VALUE_TYPE *, const char *,
 215                                          int, enum machine_mode));
 216
 217 extern void real_2expN          PARAMS ((REAL_VALUE_TYPE *, int));
 218
 219 extern unsigned int real_hash   PARAMS ((const REAL_VALUE_TYPE *));
 220
 221
 222 /* Target formats defined in real.c.  */
 223 extern const struct real_format ieee_single_format;
 224 extern const struct real_format ieee_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_128_format;
 228 extern const struct real_format ibm_extended_format;
 229 extern const struct real_format ieee_quad_format;
 230 extern const struct real_format vax_f_format;
 231 extern const struct real_format vax_d_format;
 232 extern const struct real_format vax_g_format;
 233 extern const struct real_format i370_single_format;
 234 extern const struct real_format i370_double_format;
 235 extern const struct real_format c4x_single_format;
 236 extern const struct real_format c4x_extended_format;
 237 extern const struct real_format real_internal_format;
 238
 239
 240 /* ====================================================================== */
 241 /* Crap.  */
 242
 243 #define REAL_ARITHMETIC(value, code, d1, d2) \
 244   real_arithmetic (&(value), code, &(d1), &(d2))
 245
 246 #define REAL_VALUES_IDENTICAL(x, y)     real_identical (&(x), &(y))
 247 #define REAL_VALUES_EQUAL(x, y)         real_compare (EQ_EXPR, &(x), &(y))
 248 #define REAL_VALUES_LESS(x, y)          real_compare (LT_EXPR, &(x), &(y))
 249
 250 /* Determine whether a floating-point value X is infinite.  */
 251 #define REAL_VALUE_ISINF(x)             real_isinf (&(x))
 252
 253 /* Determine whether a floating-point value X is a NaN.  */
 254 #define REAL_VALUE_ISNAN(x)             real_isnan (&(x))
 255
 256 /* Determine whether a floating-point value X is negative.  */
 257 #define REAL_VALUE_NEGATIVE(x)          real_isneg (&(x))
 258
 259 /* Determine whether a floating-point value X is minus zero.  */
 260 #define REAL_VALUE_MINUS_ZERO(x)        real_isnegzero (&(x))
 261
 262 /* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
 263 #define REAL_VALUE_TO_TARGET_LONG_DOUBLE(IN, OUT)                       \
 264   real_to_target (OUT, &(IN),                                           \
 265                   mode_for_size (LONG_DOUBLE_TYPE_SIZE, MODE_FLOAT, 0))
 266
 267 #define REAL_VALUE_TO_TARGET_DOUBLE(IN, OUT) \
 268   real_to_target (OUT, &(IN), mode_for_size (64, MODE_FLOAT, 0))
 269
 270 /* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
 271 #define REAL_VALUE_TO_TARGET_SINGLE(IN, OUT) \
 272   ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_FLOAT, 0)))
 273
 274 #define REAL_VALUE_FROM_INT(r, lo, hi, mode) \
 275   real_from_integer (&(r), mode, lo, hi, 0)
 276
 277 #define REAL_VALUE_FROM_UNSIGNED_INT(r, lo, hi, mode) \
 278   real_from_integer (&(r), mode, lo, hi, 1)
 279
 280 extern REAL_VALUE_TYPE real_value_truncate PARAMS ((enum machine_mode,
 281                                                     REAL_VALUE_TYPE));
 282
 283 #define REAL_VALUE_TO_INT(plow, phigh, r) \
 284   real_to_integer2 (plow, phigh, &(r))
 285
 286 extern REAL_VALUE_TYPE real_arithmetic2 PARAMS ((int, const REAL_VALUE_TYPE *,
 287                                                  const REAL_VALUE_TYPE *));
 288
 289 #define REAL_VALUE_NEGATE(X) \
 290   real_arithmetic2 (NEGATE_EXPR, &(X), NULL)
 291
 292 #define REAL_VALUE_ABS(X) \
 293   real_arithmetic2 (ABS_EXPR, &(X), NULL)
 294
 295 extern int significand_size PARAMS ((enum machine_mode));
 296
 297 extern REAL_VALUE_TYPE real_from_string2 PARAMS ((const char *,
 298                                                   enum machine_mode));
 299
 300 #define REAL_VALUE_ATOF(s, m) \
 301   real_from_string2 (s, m)
 302
 303 #define CONST_DOUBLE_ATOF(s, m) \
 304   CONST_DOUBLE_FROM_REAL_VALUE (real_from_string2 (s, m), m)
 305
 306 #define REAL_VALUE_FIX(r) \
 307   real_to_integer (&(r))
 308
 309 /* ??? Not quite right.  */
 310 #define REAL_VALUE_UNSIGNED_FIX(r) \
 311   real_to_integer (&(r))
 312
 313 /* ??? These were added for Paranoia support.  */
 314
 315 /* Return floor log2(R).  */
 316 extern int real_exponent        PARAMS ((const REAL_VALUE_TYPE *));
 317
 318 /* R = A * 2**EXP.  */
 319 extern void real_ldexp          PARAMS ((REAL_VALUE_TYPE *,
 320                                          const REAL_VALUE_TYPE *, int));
 321
 322 /* **** End of software floating point emulator interface macros **** */
 323 \f
 324 /* Constant real values 0, 1, 2, and -1.  */
 325
 326 extern REAL_VALUE_TYPE dconst0;
 327 extern REAL_VALUE_TYPE dconst1;
 328 extern REAL_VALUE_TYPE dconst2;
 329 extern REAL_VALUE_TYPE dconstm1;
 330
 331 /* Function to return a real value (not a tree node)
 332    from a given integer constant.  */
 333 REAL_VALUE_TYPE real_value_from_int_cst PARAMS ((union tree_node *,
 334                                                  union tree_node *));
 335
 336 /* Given a CONST_DOUBLE in FROM, store into TO the value it represents.  */
 337 #define REAL_VALUE_FROM_CONST_DOUBLE(to, from) \
 338   memcpy (&(to), &CONST_DOUBLE_LOW ((from)), sizeof (REAL_VALUE_TYPE))
 339
 340 /* Return a CONST_DOUBLE with value R and mode M.  */
 341 #define CONST_DOUBLE_FROM_REAL_VALUE(r, m) \
 342   const_double_from_real_value (r, m)
 343 extern rtx const_double_from_real_value PARAMS ((REAL_VALUE_TYPE,
 344                                                  enum machine_mode));
 345
 346 /* Replace R by 1/R in the given machine mode, if the result is exact.  */
 347 extern bool exact_real_inverse  PARAMS ((enum machine_mode, REAL_VALUE_TYPE *));
 348
 349 /* In tree.c: wrap up a REAL_VALUE_TYPE in a tree node.  */
 350 extern tree build_real                  PARAMS ((tree, REAL_VALUE_TYPE));
 351
 352 /* Calculate R as the square root of X in the given machine mode.  */
 353 extern void real_sqrt                   PARAMS ((REAL_VALUE_TYPE *,
 354                                                  enum machine_mode,
 355                                                  const REAL_VALUE_TYPE *));
 356
 357 #endif /* ! GCC_REAL_H */