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   /* Properties of the format.  */
 128   bool has_nans;
 129   bool has_inf;
 130   bool has_denorm;
 131   bool has_signed_zero;
 132   bool qnan_msb_set;
 133 };
 134
 135
 136 /* The target format used for each floating floating point mode.
 137    Indexed by MODE - QFmode.  */
 138 extern const struct real_format *real_format_for_mode[TFmode - QFmode + 1];
 139
 140
 141 /* Declare functions in real.c.  */
 142
 143 /* Binary or unary arithmetic on tree_code.  */
 144 extern void real_arithmetic     PARAMS ((REAL_VALUE_TYPE *, int,
 145                                          const REAL_VALUE_TYPE *,
 146                                          const REAL_VALUE_TYPE *));
 147
 148 /* Compare reals by tree_code.  */
 149 extern bool real_compare        PARAMS ((int, const REAL_VALUE_TYPE *,
 150                                          const REAL_VALUE_TYPE *));
 151
 152 /* Determine whether a floating-point value X is infinite.  */
 153 extern bool real_isinf          PARAMS ((const REAL_VALUE_TYPE *));
 154
 155 /* Determine whether a floating-point value X is a NaN.  */
 156 extern bool real_isnan          PARAMS ((const REAL_VALUE_TYPE *));
 157
 158 /* Determine whether a floating-point value X is negative.  */
 159 extern bool real_isneg          PARAMS ((const REAL_VALUE_TYPE *));
 160
 161 /* Determine whether a floating-point value X is minus zero.  */
 162 extern bool real_isnegzero      PARAMS ((const REAL_VALUE_TYPE *));
 163
 164 /* Compare two floating-point objects for bitwise identity.  */
 165 extern bool real_identical      PARAMS ((const REAL_VALUE_TYPE *,
 166                                          const REAL_VALUE_TYPE *));
 167
 168 /* Extend or truncate to a new mode.  */
 169 extern void real_convert        PARAMS ((REAL_VALUE_TYPE *,
 170                                          enum machine_mode,
 171                                          const REAL_VALUE_TYPE *));
 172
 173 /* Return true if truncating to NEW is exact.  */
 174 extern bool exact_real_truncate PARAMS ((enum machine_mode,
 175                                          const REAL_VALUE_TYPE *));
 176
 177 /* Render R as a decimal floating point constant.  */
 178 extern void real_to_decimal     PARAMS ((char *, const REAL_VALUE_TYPE *,
 179                                          size_t, size_t, int));
 180
 181 /* Render R as a hexadecimal floating point constant.  */
 182 extern void real_to_hexadecimal PARAMS ((char *, const REAL_VALUE_TYPE *,
 183                                          size_t, size_t, int));
 184
 185 /* Render R as an integer.  */
 186 extern HOST_WIDE_INT real_to_integer PARAMS ((const REAL_VALUE_TYPE *));
 187 extern void real_to_integer2 PARAMS ((HOST_WIDE_INT *, HOST_WIDE_INT *,
 188                                       const REAL_VALUE_TYPE *));
 189
 190 /* Initialize R from a decimal or hexadecimal string.  */
 191 extern void real_from_string    PARAMS ((REAL_VALUE_TYPE *, const char *));
 192
 193 /* Initialize R from an integer pair HIGH/LOW.  */
 194 extern void real_from_integer   PARAMS ((REAL_VALUE_TYPE *,
 195                                          enum machine_mode,
 196                                          unsigned HOST_WIDE_INT,
 197                                          HOST_WIDE_INT, int));
 198
 199 extern long real_to_target_fmt  PARAMS ((long *, const REAL_VALUE_TYPE *,
 200                                          const struct real_format *));
 201 extern long real_to_target      PARAMS ((long *, const REAL_VALUE_TYPE *,
 202                                          enum machine_mode));
 203
 204 extern void real_from_target_fmt PARAMS ((REAL_VALUE_TYPE *, const long *,
 205                                           const struct real_format *));
 206 extern void real_from_target    PARAMS ((REAL_VALUE_TYPE *, const long *,
 207                                          enum machine_mode));
 208
 209 extern void real_inf            PARAMS ((REAL_VALUE_TYPE *));
 210
 211 extern bool real_nan            PARAMS ((REAL_VALUE_TYPE *, const char *,
 212                                          int, enum machine_mode));
 213
 214 extern void real_2expN          PARAMS ((REAL_VALUE_TYPE *, int));
 215
 216 extern unsigned int real_hash   PARAMS ((const REAL_VALUE_TYPE *));
 217
 218
 219 /* Target formats defined in real.c.  */
 220 extern const struct real_format ieee_single_format;
 221 extern const struct real_format ieee_double_format;
 222 extern const struct real_format ieee_extended_motorola_format;
 223 extern const struct real_format ieee_extended_intel_96_format;
 224 extern const struct real_format ieee_extended_intel_128_format;
 225 extern const struct real_format ibm_extended_format;
 226 extern const struct real_format ieee_quad_format;
 227 extern const struct real_format vax_f_format;
 228 extern const struct real_format vax_d_format;
 229 extern const struct real_format vax_g_format;
 230 extern const struct real_format i370_single_format;
 231 extern const struct real_format i370_double_format;
 232 extern const struct real_format c4x_single_format;
 233 extern const struct real_format c4x_extended_format;
 234
 235
 236 /* ====================================================================== */
 237 /* Crap.  */
 238
 239 #define REAL_ARITHMETIC(value, code, d1, d2) \
 240   real_arithmetic (&(value), code, &(d1), &(d2))
 241
 242 #define REAL_VALUES_IDENTICAL(x, y)     real_identical (&(x), &(y))
 243 #define REAL_VALUES_EQUAL(x, y)         real_compare (EQ_EXPR, &(x), &(y))
 244 #define REAL_VALUES_LESS(x, y)          real_compare (LT_EXPR, &(x), &(y))
 245
 246 /* Determine whether a floating-point value X is infinite.  */
 247 #define REAL_VALUE_ISINF(x)             real_isinf (&(x))
 248
 249 /* Determine whether a floating-point value X is a NaN.  */
 250 #define REAL_VALUE_ISNAN(x)             real_isnan (&(x))
 251
 252 /* Determine whether a floating-point value X is negative.  */
 253 #define REAL_VALUE_NEGATIVE(x)          real_isneg (&(x))
 254
 255 /* Determine whether a floating-point value X is minus zero.  */
 256 #define REAL_VALUE_MINUS_ZERO(x)        real_isnegzero (&(x))
 257
 258 /* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
 259 #define REAL_VALUE_TO_TARGET_LONG_DOUBLE(IN, OUT)                       \
 260   real_to_target (OUT, &(IN),                                           \
 261                   mode_for_size (LONG_DOUBLE_TYPE_SIZE, MODE_FLOAT, 0))
 262
 263 #define REAL_VALUE_TO_TARGET_DOUBLE(IN, OUT) \
 264   real_to_target (OUT, &(IN), mode_for_size (64, MODE_FLOAT, 0))
 265
 266 /* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
 267 #define REAL_VALUE_TO_TARGET_SINGLE(IN, OUT) \
 268   ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_FLOAT, 0)))
 269
 270 #define REAL_VALUE_FROM_INT(r, lo, hi, mode) \
 271   real_from_integer (&(r), mode, lo, hi, 0)
 272
 273 #define REAL_VALUE_FROM_UNSIGNED_INT(r, lo, hi, mode) \
 274   real_from_integer (&(r), mode, lo, hi, 1)
 275
 276 extern REAL_VALUE_TYPE real_value_truncate PARAMS ((enum machine_mode,
 277                                                     REAL_VALUE_TYPE));
 278
 279 #define REAL_VALUE_TO_INT(plow, phigh, r) \
 280   real_to_integer2 (plow, phigh, &(r))
 281
 282 extern REAL_VALUE_TYPE real_arithmetic2 PARAMS ((int, const REAL_VALUE_TYPE *,
 283                                                  const REAL_VALUE_TYPE *));
 284
 285 #define REAL_VALUE_NEGATE(X) \
 286   real_arithmetic2 (NEGATE_EXPR, &(X), NULL)
 287
 288 #define REAL_VALUE_ABS(X) \
 289   real_arithmetic2 (ABS_EXPR, &(X), NULL)
 290
 291 extern int significand_size PARAMS ((enum machine_mode));
 292
 293 extern REAL_VALUE_TYPE real_from_string2 PARAMS ((const char *,
 294                                                   enum machine_mode));
 295
 296 #define REAL_VALUE_ATOF(s, m) \
 297   real_from_string2 (s, m)
 298
 299 #define CONST_DOUBLE_ATOF(s, m) \
 300   CONST_DOUBLE_FROM_REAL_VALUE (real_from_string2 (s, m), m)
 301
 302 #define REAL_VALUE_FIX(r) \
 303   real_to_integer (&(r))
 304
 305 /* ??? Not quite right.  */
 306 #define REAL_VALUE_UNSIGNED_FIX(r) \
 307   real_to_integer (&(r))
 308
 309 /* ??? These were added for Paranoia support.  */
 310
 311 /* Return floor log2(R).  */
 312 extern int real_exponent        PARAMS ((const REAL_VALUE_TYPE *));
 313
 314 /* R = A * 2**EXP.  */
 315 extern void real_ldexp          PARAMS ((REAL_VALUE_TYPE *,
 316                                          const REAL_VALUE_TYPE *, int));
 317
 318 /* **** End of software floating point emulator interface macros **** */
 319 \f
 320 /* Constant real values 0, 1, 2, and -1.  */
 321
 322 extern REAL_VALUE_TYPE dconst0;
 323 extern REAL_VALUE_TYPE dconst1;
 324 extern REAL_VALUE_TYPE dconst2;
 325 extern REAL_VALUE_TYPE dconstm1;
 326
 327 /* Function to return a real value (not a tree node)
 328    from a given integer constant.  */
 329 REAL_VALUE_TYPE real_value_from_int_cst PARAMS ((union tree_node *,
 330                                                  union tree_node *));
 331
 332 /* Given a CONST_DOUBLE in FROM, store into TO the value it represents.  */
 333 #define REAL_VALUE_FROM_CONST_DOUBLE(to, from) \
 334   memcpy (&(to), &CONST_DOUBLE_LOW ((from)), sizeof (REAL_VALUE_TYPE))
 335
 336 /* Return a CONST_DOUBLE with value R and mode M.  */
 337 #define CONST_DOUBLE_FROM_REAL_VALUE(r, m) \
 338   const_double_from_real_value (r, m)
 339 extern rtx const_double_from_real_value PARAMS ((REAL_VALUE_TYPE,
 340                                                  enum machine_mode));
 341
 342 /* Replace R by 1/R in the given machine mode, if the result is exact.  */
 343 extern bool exact_real_inverse  PARAMS ((enum machine_mode, REAL_VALUE_TYPE *));
 344
 345 /* In tree.c: wrap up a REAL_VALUE_TYPE in a tree node.  */
 346 extern tree build_real                  PARAMS ((tree, REAL_VALUE_TYPE));
 347
 348
 349 #endif /* ! GCC_REAL_H */