/* CGEN generic opcode support.
  Copyright (C) 2002-2024 Free Software Foundation, Inc.

  This file is part of libopcodes.

  This library is free software; you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation; either version 3, or (at your option)
  any later version.

  It is distributed in the hope that it will be useful, but WITHOUT
  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
  License for more details.

  You should have received a copy of the GNU General Public License along
  with this program; if not, write to the Free Software Foundation, Inc.,
  51 Franklin Street - Fifth Floor, Boston, MA 02110-1301, USA.  */

/* Functions for manipulating CGEN_BITSET.  */

#include "libiberty.h"
#include "cgen/bitset.h"
#include <string.h>

/* Create a bit mask.  */

CGEN_BITSET *
cgen_bitset_create (unsigned bit_count)
{
 CGEN_BITSET * mask = xmalloc (sizeof (* mask));
 cgen_bitset_init (mask, bit_count);
 return mask;
}

/* Initialize an existing bit mask.  */

void
cgen_bitset_init (CGEN_BITSET * mask, unsigned bit_count)
{
 if (! mask)
   return;
 mask->length = (bit_count / 8) + 1;
 mask->bits = xmalloc (mask->length);
 cgen_bitset_clear (mask);
}

/* Clear the bits of a bit mask.  */

void
cgen_bitset_clear (CGEN_BITSET * mask)
{
 unsigned i;

 if (! mask)
   return;

 for (i = 0; i < mask->length; ++i)
   mask->bits[i] = 0;
}

/* Add a bit to a bit mask.  */

void
cgen_bitset_add (CGEN_BITSET * mask, unsigned bit_num)
{
 int byte_ix, bit_ix;
 int bit_mask;

 if (! mask)
   return;
 byte_ix = bit_num / 8;
 bit_ix = bit_num % 8;
 bit_mask = 1 << (7 - bit_ix);
 mask->bits[byte_ix] |= bit_mask;
}

/* Set a bit mask.  */

void
cgen_bitset_set (CGEN_BITSET * mask, unsigned bit_num)
{
 if (! mask)
   return;
 cgen_bitset_clear (mask);
 cgen_bitset_add (mask, bit_num);
}

/* Test for a bit in a bit mask.
  Returns 1 if the bit is found  */

int
cgen_bitset_contains (CGEN_BITSET * mask, unsigned bit_num)
{
 int byte_ix, bit_ix;
 int bit_mask;

 if (! mask)
   return 1; /* No bit restrictions.  */

 byte_ix = bit_num / 8;
 bit_ix = 7 - (bit_num % 8);
 bit_mask = 1 << bit_ix;
 return (mask->bits[byte_ix] & bit_mask) >> bit_ix;
}

/* Compare two bit masks for equality.
  Returns 0 if they are equal.  */

int
cgen_bitset_compare (CGEN_BITSET * mask1, CGEN_BITSET * mask2)
{
 if (mask1 == mask2)
   return 0;
 if (! mask1 || ! mask2)
   return 1;
 if (mask1->length != mask2->length)
   return 1;
 return memcmp (mask1->bits, mask2->bits, mask1->length);
}

/* Test two bit masks for common bits.
  Returns 1 if a common bit is found.  */

int
cgen_bitset_intersect_p (CGEN_BITSET * mask1, CGEN_BITSET * mask2)
{
 unsigned i, limit;

 if (mask1 == mask2)
   return 1;
 if (! mask1 || ! mask2)
   return 0;
 limit = mask1->length < mask2->length ? mask1->length : mask2->length;

 for (i = 0; i < limit; ++i)
   if ((mask1->bits[i] & mask2->bits[i]))
     return 1;

 return 0;
}

/* Make a copy of a bit mask.  */

CGEN_BITSET *
cgen_bitset_copy (CGEN_BITSET * mask)
{
 CGEN_BITSET* newmask;

 if (! mask)
   return NULL;
 newmask = cgen_bitset_create ((mask->length * 8) - 1);
 memcpy (newmask->bits, mask->bits, mask->length);
 return newmask;
}

/* Combine two bit masks.  */

void
cgen_bitset_union (CGEN_BITSET * mask1, CGEN_BITSET * mask2,
                  CGEN_BITSET * result)
{
 unsigned i;

 if (! mask1 || ! mask2 || ! result
     || mask1->length != mask2->length
     || mask1->length != result->length)
   return;

 for (i = 0; i < result->length; ++i)
   result->bits[i] = mask1->bits[i] | mask2->bits[i];
}