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