gcc/double-int.h

   1 /* Operations with long integers.
   2    Copyright (C) 2006, 2007, 2008 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 union tree_node;
  61
  62 /* Constructors and conversions.  */
  63
  64 union tree_node *double_int_to_tree (union tree_node *, double_int);
  65 bool double_int_fits_to_tree_p (const union tree_node *, double_int);
  66 double_int tree_to_double_int (const union tree_node *);
  67
  68 /* Constructs double_int from integer CST.  The bits over the precision of
  69    HOST_WIDE_INT are filled with the sign bit.  */
  70
  71 static inline double_int
  72 shwi_to_double_int (HOST_WIDE_INT cst)
  73 {
  74   double_int r;
  75
  76   r.low = (unsigned HOST_WIDE_INT) cst;
  77   r.high = cst < 0 ? -1 : 0;
  78
  79   return r;
  80 }
  81
  82 /* Some useful constants.  */
  83
  84 #define double_int_minus_one (shwi_to_double_int (-1))
  85 #define double_int_zero (shwi_to_double_int (0))
  86 #define double_int_one (shwi_to_double_int (1))
  87 #define double_int_two (shwi_to_double_int (2))
  88 #define double_int_ten (shwi_to_double_int (10))
  89
  90 /* Constructs double_int from unsigned integer CST.  The bits over the
  91    precision of HOST_WIDE_INT are filled with zeros.  */
  92
  93 static inline double_int
  94 uhwi_to_double_int (unsigned HOST_WIDE_INT cst)
  95 {
  96   double_int r;
  97
  98   r.low = cst;
  99   r.high = 0;
 100
 101   return r;
 102 }
 103
 104 /* The following operations perform arithmetics modulo 2^precision,
 105    so you do not need to call double_int_ext between them, even if
 106    you are representing numbers with precision less than
 107    2 * HOST_BITS_PER_WIDE_INT bits.  */
 108
 109 double_int double_int_mul (double_int, double_int);
 110 double_int double_int_add (double_int, double_int);
 111 double_int double_int_neg (double_int);
 112
 113 /* You must ensure that double_int_ext is called on the operands
 114    of the following operations, if the precision of the numbers
 115    is less than 2 * HOST_BITS_PER_WIDE_INT bits.  */
 116 bool double_int_fits_in_hwi_p (double_int, bool);
 117 bool double_int_fits_in_shwi_p (double_int);
 118 bool double_int_fits_in_uhwi_p (double_int);
 119 HOST_WIDE_INT double_int_to_shwi (double_int);
 120 unsigned HOST_WIDE_INT double_int_to_uhwi (double_int);
 121 double_int double_int_div (double_int, double_int, bool, unsigned);
 122 double_int double_int_sdiv (double_int, double_int, unsigned);
 123 double_int double_int_udiv (double_int, double_int, unsigned);
 124 double_int double_int_mod (double_int, double_int, bool, unsigned);
 125 double_int double_int_smod (double_int, double_int, unsigned);
 126 double_int double_int_umod (double_int, double_int, unsigned);
 127 double_int double_int_divmod (double_int, double_int, bool, unsigned, double_int *);
 128 double_int double_int_sdivmod (double_int, double_int, unsigned, double_int *);
 129 double_int double_int_udivmod (double_int, double_int, unsigned, double_int *);
 130 bool double_int_negative_p (double_int);
 131 int double_int_cmp (double_int, double_int, bool);
 132 int double_int_scmp (double_int, double_int);
 133 int double_int_ucmp (double_int, double_int);
 134 void dump_double_int (FILE *, double_int, bool);
 135
 136 /* Zero and sign extension of numbers in smaller precisions.  */
 137
 138 double_int double_int_ext (double_int, unsigned, bool);
 139 double_int double_int_sext (double_int, unsigned);
 140 double_int double_int_zext (double_int, unsigned);
 141 double_int double_int_mask (unsigned);
 142
 143 #define ALL_ONES (~((unsigned HOST_WIDE_INT) 0))
 144
 145 /* The operands of the following comparison functions must be processed
 146    with double_int_ext, if their precision is less than
 147    2 * HOST_BITS_PER_WIDE_INT bits.  */
 148
 149 /* Returns true if CST is zero.  */
 150
 151 static inline bool
 152 double_int_zero_p (double_int cst)
 153 {
 154   return cst.low == 0 && cst.high == 0;
 155 }
 156
 157 /* Returns true if CST is one.  */
 158
 159 static inline bool
 160 double_int_one_p (double_int cst)
 161 {
 162   return cst.low == 1 && cst.high == 0;
 163 }
 164
 165 /* Returns true if CST is minus one.  */
 166
 167 static inline bool
 168 double_int_minus_one_p (double_int cst)
 169 {
 170   return (cst.low == ALL_ONES && cst.high == -1);
 171 }
 172
 173 /* Returns true if CST1 == CST2.  */
 174
 175 static inline bool
 176 double_int_equal_p (double_int cst1, double_int cst2)
 177 {
 178   return cst1.low == cst2.low && cst1.high == cst2.high;
 179 }
 180
 181 #ifndef GENERATOR_FILE
 182 /* Conversion to and from GMP integer representations.  */
 183
 184 void mpz_set_double_int (mpz_t, double_int, bool);
 185 double_int mpz_get_double_int (const_tree, mpz_t, bool);
 186 #endif
 187
 188 #endif /* DOUBLE_INT_H */