opcodes/cgen-bitset.c

   1 /* CGEN generic opcode support.
   2    Copyright 2002, 2005, 2007, 2009
   3    Free Software Foundation, Inc.
   4
   5    This file is part of libopcodes.
   6
   7    This library is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3, or (at your option)
  10    any later version.
  11
  12    It is distributed in the hope that it will be useful, but WITHOUT
  13    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  14    or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
  15    License for more details.
  16
  17    You should have received a copy of the GNU General Public License along
  18    with this program; if not, write to the Free Software Foundation, Inc.,
  19    51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.  */
  20
  21 /* Functions for manipulating CGEN_BITSET.  */
  22
  23 #include "libiberty.h"
  24 #include "cgen/bitset.h"
  25 #include <string.h>
  26
  27 /* Create a bit mask.  */
  28
  29 CGEN_BITSET *
  30 cgen_bitset_create (unsigned bit_count)
  31 {
  32   CGEN_BITSET * mask = xmalloc (sizeof (* mask));
  33   cgen_bitset_init (mask, bit_count);
  34   return mask;
  35 }
  36
  37 /* Initialize an existing bit mask.  */
  38
  39 void
  40 cgen_bitset_init (CGEN_BITSET * mask, unsigned bit_count)
  41 {
  42   if (! mask)
  43     return;
  44   mask->length = (bit_count / 8) + 1;
  45   mask->bits = xmalloc (mask->length);
  46   cgen_bitset_clear (mask);
  47 }
  48
  49 /* Clear the bits of a bit mask.  */
  50
  51 void
  52 cgen_bitset_clear (CGEN_BITSET * mask)
  53 {
  54   unsigned i;
  55
  56   if (! mask)
  57     return;
  58
  59   for (i = 0; i < mask->length; ++i)
  60     mask->bits[i] = 0;
  61 }
  62
  63 /* Add a bit to a bit mask.  */
  64
  65 void
  66 cgen_bitset_add (CGEN_BITSET * mask, unsigned bit_num)
  67 {
  68   int byte_ix, bit_ix;
  69   int bit_mask;
  70
  71   if (! mask)
  72     return;
  73   byte_ix = bit_num / 8;
  74   bit_ix = bit_num % 8;
  75   bit_mask = 1 << (7 - bit_ix);
  76   mask->bits[byte_ix] |= bit_mask;
  77 }
  78
  79 /* Set a bit mask.  */
  80
  81 void
  82 cgen_bitset_set (CGEN_BITSET * mask, unsigned bit_num)
  83 {
  84   if (! mask)
  85     return;
  86   cgen_bitset_clear (mask);
  87   cgen_bitset_add (mask, bit_num);
  88 }
  89
  90 /* Test for a bit in a bit mask.
  91    Returns 1 if the bit is found  */
  92
  93 int
  94 cgen_bitset_contains (CGEN_BITSET * mask, unsigned bit_num)
  95 {
  96   int byte_ix, bit_ix;
  97   int bit_mask;
  98
  99   if (! mask)
 100     return 1; /* No bit restrictions.  */
 101
 102   byte_ix = bit_num / 8;
 103   bit_ix = 7 - (bit_num % 8);
 104   bit_mask = 1 << bit_ix;
 105   return (mask->bits[byte_ix] & bit_mask) >> bit_ix;
 106 }
 107
 108 /* Compare two bit masks for equality.
 109    Returns 0 if they are equal.  */
 110
 111 int
 112 cgen_bitset_compare (CGEN_BITSET * mask1, CGEN_BITSET * mask2)
 113 {
 114   if (mask1 == mask2)
 115     return 0;
 116   if (! mask1 || ! mask2)
 117     return 1;
 118   if (mask1->length != mask2->length)
 119     return 1;
 120   return memcmp (mask1->bits, mask2->bits, mask1->length);
 121 }
 122
 123 /* Test two bit masks for common bits.
 124    Returns 1 if a common bit is found.  */
 125
 126 int
 127 cgen_bitset_intersect_p (CGEN_BITSET * mask1, CGEN_BITSET * mask2)
 128 {
 129   unsigned i, limit;
 130
 131   if (mask1 == mask2)
 132     return 1;
 133   if (! mask1 || ! mask2)
 134     return 0;
 135   limit = mask1->length < mask2->length ? mask1->length : mask2->length;
 136
 137   for (i = 0; i < limit; ++i)
 138     if ((mask1->bits[i] & mask2->bits[i]))
 139       return 1;
 140
 141   return 0;
 142 }
 143
 144 /* Make a copy of a bit mask.  */
 145
 146 CGEN_BITSET *
 147 cgen_bitset_copy (CGEN_BITSET * mask)
 148 {
 149   CGEN_BITSET* newmask;
 150
 151   if (! mask)
 152     return NULL;
 153   newmask = cgen_bitset_create ((mask->length * 8) - 1);
 154   memcpy (newmask->bits, mask->bits, mask->length);
 155   return newmask;
 156 }
 157
 158 /* Combine two bit masks.  */
 159
 160 void
 161 cgen_bitset_union (CGEN_BITSET * mask1, CGEN_BITSET * mask2,
 162                    CGEN_BITSET * result)
 163 {
 164   unsigned i;
 165
 166   if (! mask1 || ! mask2 || ! result
 167       || mask1->length != mask2->length
 168       || mask1->length != result->length)
 169     return;
 170
 171   for (i = 0; i < result->length; ++i)
 172     result->bits[i] = mask1->bits[i] | mask2->bits[i];
 173 }