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
  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 real_value_class class : 2;
  46   unsigned int sign : 1;
  47   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       #error "REAL_WIDTH > 5 not supported"
  92 #    endif
  93 #   endif
  94 #  endif
  95 # endif
  96 #endif
  97
  98
  99 /* Describes the properties of the specific target format in use.  */
 100 struct real_format
 101 {
 102   /* Move to and from the target bytes.  */
 103   void (*encode) (const struct real_format *, long *, const REAL_VALUE_TYPE *);
 104   void (*decode) (const struct real_format *, REAL_VALUE_TYPE *, const long *);
 105
 106   /* The radix of the exponent and digits of the significand.  */
 107   int b;
 108
 109   /* log2(b).  */
 110   int log2_b;
 111
 112   /* Size of the significand in digits of radix B.  */
 113   int p;
 114
 115   /* The minimum negative integer, x, such that b**(x-1) is normalized.  */
 116   int emin;
 117
 118   /* The maximum integer, x, such that b**(x-1) is representable.  */
 119   int emax;
 120
 121   /* Properties of the format.  */
 122   bool has_nans;
 123   bool has_inf;
 124   bool has_denorm;
 125   bool has_signed_zero;
 126   bool qnan_msb_set;
 127 };
 128
 129
 130 /* The target format used for each floating floating point mode.
 131    Indexed by MODE - QFmode.  */
 132 extern const struct real_format *real_format_for_mode[TFmode - QFmode + 1];
 133
 134
 135 /* Declare functions in real.c.  */
 136
 137 /* Binary or unary arithmetic on tree_code.  */
 138 extern void real_arithmetic     PARAMS ((REAL_VALUE_TYPE *, int,
 139                                          const REAL_VALUE_TYPE *,
 140                                          const REAL_VALUE_TYPE *));
 141
 142 /* Compare reals by tree_code.  */
 143 extern bool real_compare        PARAMS ((int, const REAL_VALUE_TYPE *,
 144                                          const REAL_VALUE_TYPE *));
 145
 146 /* Determine whether a floating-point value X is infinite.  */
 147 extern bool real_isinf          PARAMS ((const REAL_VALUE_TYPE *));
 148
 149 /* Determine whether a floating-point value X is a NaN.  */
 150 extern bool real_isnan          PARAMS ((const REAL_VALUE_TYPE *));
 151
 152 /* Determine whether a floating-point value X is negative.  */
 153 extern bool real_isneg          PARAMS ((const REAL_VALUE_TYPE *));
 154
 155 /* Determine whether a floating-point value X is minus zero.  */
 156 extern bool real_isnegzero      PARAMS ((const REAL_VALUE_TYPE *));
 157
 158 /* Compare two floating-point objects for bitwise identity.  */
 159 extern bool real_identical      PARAMS ((const REAL_VALUE_TYPE *,
 160                                          const REAL_VALUE_TYPE *));
 161
 162 /* Extend or truncate to a new mode.  */
 163 extern void real_convert        PARAMS ((REAL_VALUE_TYPE *,
 164                                          enum machine_mode,
 165                                          const REAL_VALUE_TYPE *));
 166
 167 /* Return true if truncating to NEW is exact.  */
 168 extern bool exact_real_truncate PARAMS ((enum machine_mode,
 169                                          const REAL_VALUE_TYPE *));
 170
 171 /* Render R as a decimal floating point constant.  */
 172 extern void real_to_decimal     PARAMS ((char *, const REAL_VALUE_TYPE *,
 173                                          int));
 174
 175 /* Render R as a hexadecimal floating point constant.  */
 176 extern void real_to_hexadecimal PARAMS ((char *, const REAL_VALUE_TYPE *,
 177                                          int));
 178
 179 /* Render R as an integer.  */
 180 extern HOST_WIDE_INT real_to_integer PARAMS ((const REAL_VALUE_TYPE *));
 181 extern void real_to_integer2 PARAMS ((HOST_WIDE_INT *, HOST_WIDE_INT *,
 182                                       const REAL_VALUE_TYPE *));
 183
 184 /* Initialize R from a decimal or hexadecimal string.  */
 185 extern void real_from_string    PARAMS ((REAL_VALUE_TYPE *, const char *));
 186
 187 /* Initialize R from an integer pair HIGH/LOW.  */
 188 extern void real_from_integer   PARAMS ((REAL_VALUE_TYPE *,
 189                                          enum machine_mode,
 190                                          unsigned HOST_WIDE_INT,
 191                                          HOST_WIDE_INT, int));
 192
 193 extern long real_to_target_fmt  PARAMS ((long *, const REAL_VALUE_TYPE *,
 194                                          const struct real_format *));
 195 extern long real_to_target      PARAMS ((long *, const REAL_VALUE_TYPE *,
 196                                          enum machine_mode));
 197
 198 extern void real_from_target_fmt PARAMS ((REAL_VALUE_TYPE *, const long *,
 199                                           const struct real_format *));
 200 extern void real_from_target    PARAMS ((REAL_VALUE_TYPE *, const long *,
 201                                          enum machine_mode));
 202
 203 extern void real_inf            PARAMS ((REAL_VALUE_TYPE *));
 204
 205 extern bool real_nan            PARAMS ((REAL_VALUE_TYPE *, const char *,
 206                                          int, enum machine_mode));
 207
 208 extern void real_2expN          PARAMS ((REAL_VALUE_TYPE *, int));
 209
 210 extern unsigned int real_hash   PARAMS ((const REAL_VALUE_TYPE *));
 211
 212
 213 /* Target formats defined in real.c.  */
 214 extern const struct real_format ieee_single_format;
 215 extern const struct real_format ieee_double_format;
 216 extern const struct real_format ieee_extended_motorola_format;
 217 extern const struct real_format ieee_extended_intel_96_format;
 218 extern const struct real_format ieee_extended_intel_128_format;
 219 extern const struct real_format ieee_quad_format;
 220 extern const struct real_format vax_f_format;
 221 extern const struct real_format vax_d_format;
 222 extern const struct real_format vax_g_format;
 223 extern const struct real_format i370_single_format;
 224 extern const struct real_format i370_double_format;
 225 extern const struct real_format c4x_single_format;
 226 extern const struct real_format c4x_extended_format;
 227
 228
 229 /* ====================================================================== */
 230 /* Crap.  */
 231
 232 #define REAL_ARITHMETIC(value, code, d1, d2) \
 233   real_arithmetic (&(value), code, &(d1), &(d2))
 234
 235 #define REAL_VALUES_IDENTICAL(x, y)     real_identical (&(x), &(y))
 236 #define REAL_VALUES_EQUAL(x, y)         real_compare (EQ_EXPR, &(x), &(y))
 237 #define REAL_VALUES_LESS(x, y)          real_compare (LT_EXPR, &(x), &(y))
 238
 239 /* Determine whether a floating-point value X is infinite.  */
 240 #define REAL_VALUE_ISINF(x)             real_isinf (&(x))
 241
 242 /* Determine whether a floating-point value X is a NaN.  */
 243 #define REAL_VALUE_ISNAN(x)             real_isnan (&(x))
 244
 245 /* Determine whether a floating-point value X is negative.  */
 246 #define REAL_VALUE_NEGATIVE(x)          real_isneg (&(x))
 247
 248 /* Determine whether a floating-point value X is minus zero.  */
 249 #define REAL_VALUE_MINUS_ZERO(x)        real_isnegzero (&(x))
 250
 251 /* IN is a REAL_VALUE_TYPE.  OUT is an array of longs.  */
 252 #define REAL_VALUE_TO_TARGET_LONG_DOUBLE(IN, OUT)                       \
 253   real_to_target (OUT, &(IN),                                           \
 254                   mode_for_size (LONG_DOUBLE_TYPE_SIZE, MODE_FLOAT, 0))
 255
 256 #define REAL_VALUE_TO_TARGET_DOUBLE(IN, OUT) \
 257   real_to_target (OUT, &(IN), mode_for_size (64, MODE_FLOAT, 0))
 258
 259 /* IN is a REAL_VALUE_TYPE.  OUT is a long.  */
 260 #define REAL_VALUE_TO_TARGET_SINGLE(IN, OUT) \
 261   ((OUT) = real_to_target (NULL, &(IN), mode_for_size (32, MODE_FLOAT, 0)))
 262
 263 #define REAL_VALUE_TO_DECIMAL(r, s, dig) \
 264   real_to_decimal (s, &(r), dig)
 265
 266 #define REAL_VALUE_FROM_INT(r, lo, hi, mode) \
 267   real_from_integer (&(r), mode, lo, hi, 0)
 268
 269 #define REAL_VALUE_FROM_UNSIGNED_INT(r, lo, hi, mode) \
 270   real_from_integer (&(r), mode, lo, hi, 1)
 271
 272 extern REAL_VALUE_TYPE real_value_truncate PARAMS ((enum machine_mode,
 273                                                     REAL_VALUE_TYPE));
 274
 275 #define REAL_VALUE_TO_INT(plow, phigh, r) \
 276   real_to_integer2 (plow, phigh, &(r))
 277
 278 extern REAL_VALUE_TYPE real_arithmetic2 PARAMS ((int, const REAL_VALUE_TYPE *,
 279                                                  const REAL_VALUE_TYPE *));
 280
 281 #define REAL_VALUE_NEGATE(X) \
 282   real_arithmetic2 (NEGATE_EXPR, &(X), NULL)
 283
 284 #define REAL_VALUE_ABS(X) \
 285   real_arithmetic2 (ABS_EXPR, &(X), NULL)
 286
 287 extern int significand_size PARAMS ((enum machine_mode));
 288
 289 extern REAL_VALUE_TYPE real_from_string2 PARAMS ((const char *,
 290                                                   enum machine_mode));
 291
 292 #define REAL_VALUE_ATOF(s, m) \
 293   real_from_string2 (s, m)
 294
 295 #define CONST_DOUBLE_ATOF(s, m) \
 296   CONST_DOUBLE_FROM_REAL_VALUE (real_from_string2 (s, m), m)
 297
 298 #define REAL_VALUE_FIX(r) \
 299   real_to_integer (&(r))
 300
 301 /* ??? Not quite right.  */
 302 #define REAL_VALUE_UNSIGNED_FIX(r) \
 303   real_to_integer (&(r))
 304
 305 /* ??? These were added for Paranoia support.  */
 306
 307 /* Return floor log2(R).  */
 308 extern int real_exponent        PARAMS ((const REAL_VALUE_TYPE *));
 309
 310 /* R = A * 2**EXP.  */
 311 extern void real_ldexp          PARAMS ((REAL_VALUE_TYPE *,
 312                                          const REAL_VALUE_TYPE *, int));
 313
 314 /* **** End of software floating point emulator interface macros **** */
 315 \f
 316 /* Constant real values 0, 1, 2, and -1.  */
 317
 318 extern REAL_VALUE_TYPE dconst0;
 319 extern REAL_VALUE_TYPE dconst1;
 320 extern REAL_VALUE_TYPE dconst2;
 321 extern REAL_VALUE_TYPE dconstm1;
 322
 323 /* Function to return a real value (not a tree node)
 324    from a given integer constant.  */
 325 REAL_VALUE_TYPE real_value_from_int_cst PARAMS ((union tree_node *,
 326                                                  union tree_node *));
 327
 328 /* Given a CONST_DOUBLE in FROM, store into TO the value it represents.  */
 329 #define REAL_VALUE_FROM_CONST_DOUBLE(to, from) \
 330   memcpy (&(to), &CONST_DOUBLE_LOW ((from)), sizeof (REAL_VALUE_TYPE))
 331
 332 /* Return a CONST_DOUBLE with value R and mode M.  */
 333 #define CONST_DOUBLE_FROM_REAL_VALUE(r, m) \
 334   const_double_from_real_value (r, m)
 335 extern rtx const_double_from_real_value PARAMS ((REAL_VALUE_TYPE,
 336                                                  enum machine_mode));
 337
 338 /* Replace R by 1/R in the given machine mode, if the result is exact.  */
 339 extern bool exact_real_inverse  PARAMS ((enum machine_mode, REAL_VALUE_TYPE *));
 340
 341 /* In tree.c: wrap up a REAL_VALUE_TYPE in a tree node.  */
 342 extern tree build_real                  PARAMS ((tree, REAL_VALUE_TYPE));
 343
 344
 345 #endif /* ! GCC_REAL_H */