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 tree double_int_to_tree (tree, double_int);
  65 bool double_int_fits_to_tree_p (const_tree, double_int);
  66
  67 /* Constructs double_int from tree CST.  */
  68
  69 #define tree_to_double_int(cst) (TREE_INT_CST (cst))
  70
  71 /* Constructs double_int from integer CST.  The bits over the precision of
  72    HOST_WIDE_INT are filled with the sign bit.  */
  73
  74 static inline double_int
  75 shwi_to_double_int (HOST_WIDE_INT cst)
  76 {
  77   double_int r;
  78
  79   r.low = (unsigned HOST_WIDE_INT) cst;
  80   r.high = cst < 0 ? -1 : 0;
  81
  82   return r;
  83 }
  84
  85 /* Some useful constants.  */
  86
  87 #define double_int_minus_one (shwi_to_double_int (-1))
  88 #define double_int_zero (shwi_to_double_int (0))
  89 #define double_int_one (shwi_to_double_int (1))
  90 #define double_int_two (shwi_to_double_int (2))
  91 #define double_int_ten (shwi_to_double_int (10))
  92
  93 /* Constructs double_int from unsigned integer CST.  The bits over the
  94    precision of HOST_WIDE_INT are filled with zeros.  */
  95
  96 static inline double_int
  97 uhwi_to_double_int (unsigned HOST_WIDE_INT cst)
  98 {
  99   double_int r;
 100
 101   r.low = cst;
 102   r.high = 0;
 103
 104   return r;
 105 }
 106
 107 /* The following operations perform arithmetics modulo 2^precision,
 108    so you do not need to call double_int_ext between them, even if
 109    you are representing numbers with precision less than
 110    2 * HOST_BITS_PER_WIDE_INT bits.  */
 111
 112 double_int double_int_mul (double_int, double_int);
 113 double_int double_int_add (double_int, double_int);
 114 double_int double_int_neg (double_int);
 115
 116 /* You must ensure that double_int_ext is called on the operands
 117    of the following operations, if the precision of the numbers
 118    is less than 2 * HOST_BITS_PER_WIDE_INT bits.  */
 119 bool double_int_fits_in_hwi_p (double_int, bool);
 120 bool double_int_fits_in_shwi_p (double_int);
 121 bool double_int_fits_in_uhwi_p (double_int);
 122 HOST_WIDE_INT double_int_to_shwi (double_int);
 123 unsigned HOST_WIDE_INT double_int_to_uhwi (double_int);
 124 double_int double_int_div (double_int, double_int, bool, unsigned);
 125 double_int double_int_sdiv (double_int, double_int, unsigned);
 126 double_int double_int_udiv (double_int, double_int, unsigned);
 127 double_int double_int_mod (double_int, double_int, bool, unsigned);
 128 double_int double_int_smod (double_int, double_int, unsigned);
 129 double_int double_int_umod (double_int, double_int, unsigned);
 130 double_int double_int_divmod (double_int, double_int, bool, unsigned, double_int *);
 131 double_int double_int_sdivmod (double_int, double_int, unsigned, double_int *);
 132 double_int double_int_udivmod (double_int, double_int, unsigned, double_int *);
 133
 134 /* Logical operations.  */
 135 static inline double_int
 136 double_int_not (double_int a)
 137 {
 138   a.low = ~a.low;
 139   a.high = ~ a.high;
 140   return a;
 141 }
 142
 143 /* Shift operations.  */
 144 double_int double_int_lshift (double_int, HOST_WIDE_INT, unsigned int, bool);
 145 double_int double_int_rshift (double_int, HOST_WIDE_INT, unsigned int, bool);
 146
 147 /* Returns true if CST is negative.  Of course, CST is considered to
 148    be signed.  */
 149
 150 static inline bool
 151 double_int_negative_p (double_int cst)
 152 {
 153   return cst.high < 0;
 154 }
 155
 156 int double_int_cmp (double_int, double_int, bool);
 157 int double_int_scmp (double_int, double_int);
 158 int double_int_ucmp (double_int, double_int);
 159 void dump_double_int (FILE *, double_int, bool);
 160
 161 /* Zero and sign extension of numbers in smaller precisions.  */
 162
 163 double_int double_int_ext (double_int, unsigned, bool);
 164 double_int double_int_sext (double_int, unsigned);
 165 double_int double_int_zext (double_int, unsigned);
 166 double_int double_int_mask (unsigned);
 167
 168 #define ALL_ONES (~((unsigned HOST_WIDE_INT) 0))
 169
 170 /* The operands of the following comparison functions must be processed
 171    with double_int_ext, if their precision is less than
 172    2 * HOST_BITS_PER_WIDE_INT bits.  */
 173
 174 /* Returns true if CST is zero.  */
 175
 176 static inline bool
 177 double_int_zero_p (double_int cst)
 178 {
 179   return cst.low == 0 && cst.high == 0;
 180 }
 181
 182 /* Returns true if CST is one.  */
 183
 184 static inline bool
 185 double_int_one_p (double_int cst)
 186 {
 187   return cst.low == 1 && cst.high == 0;
 188 }
 189
 190 /* Returns true if CST is minus one.  */
 191
 192 static inline bool
 193 double_int_minus_one_p (double_int cst)
 194 {
 195   return (cst.low == ALL_ONES && cst.high == -1);
 196 }
 197
 198 /* Returns true if CST1 == CST2.  */
 199
 200 static inline bool
 201 double_int_equal_p (double_int cst1, double_int cst2)
 202 {
 203   return cst1.low == cst2.low && cst1.high == cst2.high;
 204 }
 205
 206
 207 /* Legacy interface with decomposed high/low parts.  */
 208
 209 extern tree force_fit_type_double (tree, unsigned HOST_WIDE_INT, HOST_WIDE_INT,
 210                                    int, bool);
 211 extern int fit_double_type (unsigned HOST_WIDE_INT, HOST_WIDE_INT,
 212                             unsigned HOST_WIDE_INT *, HOST_WIDE_INT *,
 213                             const_tree);
 214 extern int add_double_with_sign (unsigned HOST_WIDE_INT, HOST_WIDE_INT,
 215                                  unsigned HOST_WIDE_INT, HOST_WIDE_INT,
 216                                  unsigned HOST_WIDE_INT *, HOST_WIDE_INT *,
 217                                  bool);
 218 #define add_double(l1,h1,l2,h2,lv,hv) \
 219   add_double_with_sign (l1, h1, l2, h2, lv, hv, false)
 220 extern int neg_double (unsigned HOST_WIDE_INT, HOST_WIDE_INT,
 221                        unsigned HOST_WIDE_INT *, HOST_WIDE_INT *);
 222 extern int mul_double_with_sign (unsigned HOST_WIDE_INT, HOST_WIDE_INT,
 223                                  unsigned HOST_WIDE_INT, HOST_WIDE_INT,
 224                                  unsigned HOST_WIDE_INT *, HOST_WIDE_INT *,
 225                                  bool);
 226 #define mul_double(l1,h1,l2,h2,lv,hv) \
 227   mul_double_with_sign (l1, h1, l2, h2, lv, hv, false)
 228 extern void lshift_double (unsigned HOST_WIDE_INT, HOST_WIDE_INT,
 229                            HOST_WIDE_INT, unsigned int,
 230                            unsigned HOST_WIDE_INT *, HOST_WIDE_INT *, bool);
 231 extern void rshift_double (unsigned HOST_WIDE_INT, HOST_WIDE_INT,
 232                            HOST_WIDE_INT, unsigned int,
 233                            unsigned HOST_WIDE_INT *, HOST_WIDE_INT *, bool);
 234 extern void lrotate_double (unsigned HOST_WIDE_INT, HOST_WIDE_INT,
 235                             HOST_WIDE_INT, unsigned int,
 236                             unsigned HOST_WIDE_INT *, HOST_WIDE_INT *);
 237 extern void rrotate_double (unsigned HOST_WIDE_INT, HOST_WIDE_INT,
 238                             HOST_WIDE_INT, unsigned int,
 239                             unsigned HOST_WIDE_INT *, HOST_WIDE_INT *);
 240 extern int div_and_round_double (unsigned, int, unsigned HOST_WIDE_INT,
 241                                  HOST_WIDE_INT, unsigned HOST_WIDE_INT,
 242                                  HOST_WIDE_INT, unsigned HOST_WIDE_INT *,
 243                                  HOST_WIDE_INT *, unsigned HOST_WIDE_INT *,
 244                                  HOST_WIDE_INT *);
 245
 246
 247 #ifndef GENERATOR_FILE
 248 /* Conversion to and from GMP integer representations.  */
 249
 250 void mpz_set_double_int (mpz_t, double_int, bool);
 251 double_int mpz_get_double_int (const_tree, mpz_t, bool);
 252 #endif
 253
 254 #endif /* DOUBLE_INT_H */