/* Implement POWERSET runtime actions for CHILL.
   Copyright (C) 1992,1993 Free Software Foundation, Inc.
   Author: Wilfried Moser, et al

This file is part of GNU CC.

GNU CC 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 2, or (at your option)
any later version.

GNU CC 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 GNU CC; see the file COPYING.  If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */

#define __CHILL_LIB__

#include <stdio.h>
#include "powerset.h"

/*
 * function __diffpowerset
 *
 * parameters:
 *     out		result of __diffpowerset
 *	left		powerset
 *	right		powerset
 *	bitlength	length of powerset
 *
 * returns:
 *	void
 *
 * exceptions:
 *  none
 *
 * abstract:
 *  makes a difference of 2 powersets (out = left - right)
 *
 */
void
__diffpowerset (out, left, right, bitlength)
     SET_WORD      *out;
     SET_WORD      *left;
     SET_WORD      *right;
     unsigned long  bitlength;
{
  if (bitlength <= SET_CHAR_SIZE)
    {
      *((SET_CHAR *)out) = *((SET_CHAR *)left) & ~
                           *((SET_CHAR *)right);
      MASK_UNUSED_CHAR_BITS ((SET_CHAR *)out, bitlength);
    }
  else if (bitlength <= SET_SHORT_SIZE)
    {
      *((SET_SHORT *)out) = *((SET_SHORT *)left) & ~
                            *((SET_SHORT *)right);
      MASK_UNUSED_SHORT_BITS ((SET_SHORT *)out, bitlength);
    }
  else
    {
      unsigned long len = BITS_TO_WORDS(bitlength);
      register unsigned long i;
    
      for (i = 0; i < len; i++)
	out[i] = left[i] & ~right[i];
      MASK_UNUSED_WORD_BITS ((out + len - 1), bitlength % SET_WORD_SIZE);
    }
}