gcc/double-int.h

   1 /* Operations with long integers.
   2    Copyright (C) 2006, 2007, 2008, 2010 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify it
   7 under the terms of the GNU General Public License as published by the
   8 Free Software Foundation; either version 3, or (at your option) any
   9 later version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT
  12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING3.  If not see
  18 <http://www.gnu.org/licenses/>.  */
  19
  20 #ifndef DOUBLE_INT_H
  21 #define DOUBLE_INT_H
  22
  23 #ifndef GENERATOR_FILE
  24 #include <gmp.h>
  25 #endif
  26 #include "coretypes.h"
  27
  28 /* A large integer is currently represented as a pair of HOST_WIDE_INTs.
  29    It therefore represents a number with precision of
  30    2 * HOST_BITS_PER_WIDE_INT bits (it is however possible that the
  31    internal representation will change, if numbers with greater precision
  32    are needed, so the users should not rely on it).  The representation does
  33    not contain any information about signedness of the represented value, so
  34    it can be used to represent both signed and unsigned numbers.  For
  35    operations where the results depend on signedness (division, comparisons),
  36    it must be specified separately.  For each such operation, there are three
  37    versions of the function -- double_int_op, that takes an extra UNS argument
  38    giving the signedness of the values, and double_int_sop and double_int_uop
  39    that stand for its specializations for signed and unsigned values.
  40
  41    You may also represent with numbers in smaller precision using double_int.
  42    You however need to use double_int_ext (that fills in the bits of the
  43    number over the prescribed precision with zeros or with the sign bit) before
  44    operations that do not perform arithmetics modulo 2^precision (comparisons,
  45    division), and possibly before storing the results, if you want to keep
  46    them in some canonical form).  In general, the signedness of double_int_ext
  47    should match the signedness of the operation.
  48
  49    ??? The components of double_int differ in signedness mostly for
  50    historical reasons (they replace an older structure used to represent
  51    numbers with precision higher than HOST_WIDE_INT).  It might be less
  52    confusing to have them both signed or both unsigned.  */
  53
  54 typedef struct
  55 {
  56   unsigned HOST_WIDE_INT low;
  57   HOST_WIDE_INT high;
  58 } double_int;
  59
  60 #define HOST_BITS_PER_DOUBLE_INT (2 * HOST_BITS_PER_WIDE_INT)
  61
  62 /* Constructors and conversions.  */
  63
  64 /* Constructs double_int from integer CST.  The bits over the precision of
  65    HOST_WIDE_INT are filled with the sign bit.  */
  66
  67 static inline double_int
  68 shwi_to_double_int (HOST_WIDE_INT cst)
  69 {
  70   double_int r;
  71
  72   r.low = (unsigned HOST_WIDE_INT) cst;
  73   r.high = cst < 0 ? -1 : 0;
  74
  75   return r;
  76 }
  77
  78 /* Some useful constants.  */
  79
  80 #define double_int_minus_one (shwi_to_double_int (-1))
  81 #define double_int_zero (shwi_to_double_int (0))
  82 #define double_int_one (shwi_to_double_int (1))
  83 #define double_int_two (shwi_to_double_int (2))
  84 #define double_int_ten (shwi_to_double_int (10))
  85
  86 /* Constructs double_int from unsigned integer CST.  The bits over the
  87    precision of HOST_WIDE_INT are filled with zeros.  */
  88
  89 static inline double_int
  90 uhwi_to_double_int (unsigned HOST_WIDE_INT cst)
  91 {
  92   double_int r;
  93
  94   r.low = cst;
  95   r.high = 0;
  96
  97   return r;
  98 }
  99
 100 /* Returns value of CST as a signed number.  CST must satisfy
 101    double_int_fits_in_shwi_p.  */
 102
 103 static inline HOST_WIDE_INT
 104 double_int_to_shwi (double_int cst)
 105 {
 106   return (HOST_WIDE_INT) cst.low;
 107 }
 108
 109 /* Returns value of CST as an unsigned number.  CST must satisfy
 110    double_int_fits_in_uhwi_p.  */
 111
 112 static inline unsigned HOST_WIDE_INT
 113 double_int_to_uhwi (double_int cst)
 114 {
 115   return cst.low;
 116 }
 117
 118 bool double_int_fits_in_hwi_p (double_int, bool);
 119 bool double_int_fits_in_shwi_p (double_int);
 120
 121 /* Returns true if CST fits in unsigned HOST_WIDE_INT.  */
 122
 123 static inline bool
 124 double_int_fits_in_uhwi_p (double_int cst)
 125 {
 126   return cst.high == 0;
 127 }
 128
 129 /* The following operations perform arithmetics modulo 2^precision,
 130    so you do not need to call double_int_ext between them, even if
 131    you are representing numbers with precision less than
 132    2 * HOST_BITS_PER_WIDE_INT bits.  */
 133
 134 double_int double_int_mul (double_int, double_int);
 135 double_int double_int_add (double_int, double_int);
 136 double_int double_int_neg (double_int);
 137
 138 /* You must ensure that double_int_ext is called on the operands
 139    of the following operations, if the precision of the numbers
 140    is less than 2 * HOST_BITS_PER_WIDE_INT bits.  */
 141 double_int double_int_div (double_int, double_int, bool, unsigned);
 142 double_int double_int_sdiv (double_int, double_int, unsigned);
 143 double_int double_int_udiv (double_int, double_int, unsigned);
 144 double_int double_int_mod (double_int, double_int, bool, unsigned);
 145 double_int double_int_smod (double_int, double_int, unsigned);
 146 double_int double_int_umod (double_int, double_int, unsigned);
 147 double_int double_int_divmod (double_int, double_int, bool, unsigned, double_int *);
 148 double_int double_int_sdivmod (double_int, double_int, unsigned, double_int *);
 149 double_int double_int_udivmod (double_int, double_int, unsigned, double_int *);
 150 double_int double_int_setbit (double_int, unsigned);
 151
 152 /* Logical operations.  */
 153
 154 /* Returns ~A.  */
 155
 156 static inline double_int
 157 double_int_not (double_int a)
 158 {
 159   a.low = ~a.low;
 160   a.high = ~ a.high;
 161   return a;
 162 }
 163
 164 /* Returns A | B.  */
 165
 166 static inline double_int
 167 double_int_ior (double_int a, double_int b)
 168 {
 169   a.low |= b.low;
 170   a.high |= b.high;
 171   return a;
 172 }
 173
 174 /* Returns A & B.  */
 175
 176 static inline double_int
 177 double_int_and (double_int a, double_int b)
 178 {
 179   a.low &= b.low;
 180   a.high &= b.high;
 181   return a;
 182 }
 183
 184 /* Returns A ^ B.  */
 185
 186 static inline double_int
 187 double_int_xor (double_int a, double_int b)
 188 {
 189   a.low ^= b.low;
 190   a.high ^= b.high;
 191   return a;
 192 }
 193
 194
 195 /* Shift operations.  */
 196 double_int double_int_lshift (double_int, HOST_WIDE_INT, unsigned int, bool);
 197 double_int double_int_rshift (double_int, HOST_WIDE_INT, unsigned int, bool);
 198 double_int double_int_lrotate (double_int, HOST_WIDE_INT, unsigned int);
 199 double_int double_int_rrotate (double_int, HOST_WIDE_INT, unsigned int);
 200
 201 /* Returns true if CST is negative.  Of course, CST is considered to
 202    be signed.  */
 203
 204 static inline bool
 205 double_int_negative_p (double_int cst)
 206 {
 207   return cst.high < 0;
 208 }
 209
 210 int double_int_cmp (double_int, double_int, bool);
 211 int double_int_scmp (double_int, double_int);
 212 int double_int_ucmp (double_int, double_int);
 213
 214 double_int double_int_max (double_int, double_int, bool);
 215 double_int double_int_smax (double_int, double_int);
 216 double_int double_int_umax (double_int, double_int);
 217
 218 double_int double_int_min (double_int, double_int, bool);
 219 double_int double_int_smin (double_int, double_int);
 220 double_int double_int_umin (double_int, double_int);
 221
 222 void dump_double_int (FILE *, double_int, bool);
 223
 224 /* Zero and sign extension of numbers in smaller precisions.  */
 225
 226 double_int double_int_ext (double_int, unsigned, bool);
 227 double_int double_int_sext (double_int, unsigned);
 228 double_int double_int_zext (double_int, unsigned);
 229 double_int double_int_mask (unsigned);
 230
 231 #define ALL_ONES (~((unsigned HOST_WIDE_INT) 0))
 232
 233 /* The operands of the following comparison functions must be processed
 234    with double_int_ext, if their precision is less than
 235    2 * HOST_BITS_PER_WIDE_INT bits.  */
 236
 237 /* Returns true if CST is zero.  */
 238
 239 static inline bool
 240 double_int_zero_p (double_int cst)
 241 {
 242   return cst.low == 0 && cst.high == 0;
 243 }
 244
 245 /* Returns true if CST is one.  */
 246
 247 static inline bool
 248 double_int_one_p (double_int cst)
 249 {
 250   return cst.low == 1 && cst.high == 0;
 251 }
 252
 253 /* Returns true if CST is minus one.  */
 254
 255 static inline bool
 256 double_int_minus_one_p (double_int cst)
 257 {
 258   return (cst.low == ALL_ONES && cst.high == -1);
 259 }
 260
 261 /* Returns true if CST1 == CST2.  */
 262
 263 static inline bool
 264 double_int_equal_p (double_int cst1, double_int cst2)
 265 {
 266   return cst1.low == cst2.low && cst1.high == cst2.high;
 267 }
 268
 269
 270 /* Legacy interface with decomposed high/low parts.  */
 271
 272 extern int fit_double_type (unsigned HOST_WIDE_INT, HOST_WIDE_INT,
 273                             unsigned HOST_WIDE_INT *, HOST_WIDE_INT *,
 274                             const_tree);
 275 extern int add_double_with_sign (unsigned HOST_WIDE_INT, HOST_WIDE_INT,
 276                                  unsigned HOST_WIDE_INT, HOST_WIDE_INT,
 277                                  unsigned HOST_WIDE_INT *, HOST_WIDE_INT *,
 278                                  bool);
 279 #define add_double(l1,h1,l2,h2,lv,hv) \
 280   add_double_with_sign (l1, h1, l2, h2, lv, hv, false)
 281 extern int neg_double (unsigned HOST_WIDE_INT, HOST_WIDE_INT,
 282                        unsigned HOST_WIDE_INT *, HOST_WIDE_INT *);
 283 extern int mul_double_with_sign (unsigned HOST_WIDE_INT, HOST_WIDE_INT,
 284                                  unsigned HOST_WIDE_INT, HOST_WIDE_INT,
 285                                  unsigned HOST_WIDE_INT *, HOST_WIDE_INT *,
 286                                  bool);
 287 #define mul_double(l1,h1,l2,h2,lv,hv) \
 288   mul_double_with_sign (l1, h1, l2, h2, lv, hv, false)
 289 extern void lshift_double (unsigned HOST_WIDE_INT, HOST_WIDE_INT,
 290                            HOST_WIDE_INT, unsigned int,
 291                            unsigned HOST_WIDE_INT *, HOST_WIDE_INT *, bool);
 292 extern void rshift_double (unsigned HOST_WIDE_INT, HOST_WIDE_INT,
 293                            HOST_WIDE_INT, unsigned int,
 294                            unsigned HOST_WIDE_INT *, HOST_WIDE_INT *, bool);
 295 extern int div_and_round_double (unsigned, int, unsigned HOST_WIDE_INT,
 296                                  HOST_WIDE_INT, unsigned HOST_WIDE_INT,
 297                                  HOST_WIDE_INT, unsigned HOST_WIDE_INT *,
 298                                  HOST_WIDE_INT *, unsigned HOST_WIDE_INT *,
 299                                  HOST_WIDE_INT *);
 300
 301
 302 #ifndef GENERATOR_FILE
 303 /* Conversion to and from GMP integer representations.  */
 304
 305 void mpz_set_double_int (mpz_t, double_int, bool);
 306 double_int mpz_get_double_int (const_tree, mpz_t, bool);
 307 #endif
 308
 309 #endif /* DOUBLE_INT_H */