libchill/setbits.c

   1 /* Implement POWERSET runtime actions for CHILL.
   2    Copyright (C) 1992,1993 Free Software Foundation, Inc.
   3    Author: Wilfried Moser, et al
   4
   5 This file is part of GNU CC.
   6
   7 GNU CC 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 2, or (at your option)
  10 any later version.
  11
  12 GNU CC is distributed in the hope that it will be useful,
  13 but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 GNU General Public License for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GNU CC; see the file COPYING.  If not, write to
  19 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */
  20
  21 #define __CHILL_LIB__
  22
  23 #include "config.h"
  24 #include <stdio.h>
  25 #include "powerset.h"
  26
  27 extern void __cause_ex1 (char *exname, char *file, int lineno);
  28
  29 /*
  30  * function __setbits
  31  *
  32  * parameters:
  33  *      out             result
  34  *      bitlength       length of bitstring in bits
  35  *      startbit        starting bitnumber
  36  *      endbit          ending bitnumber
  37  *
  38  * returns:
  39  *      void
  40  *
  41  * exceptions:
  42  *   rangefail
  43  *
  44  * abstract:
  45  *  set all bits from starting bitnumber to ending bitnumber
  46  *  in a powerset
  47  *
  48  */
  49 void
  50 __setbits (out, bitlength, startbit, endbit)
  51      SET_WORD      *out;
  52      unsigned long  bitlength;
  53      long  startbit;
  54      long  endbit;
  55 {
  56   unsigned long i;
  57
  58   if (out == NULL
  59       || startbit < 0
  60       || startbit >= bitlength
  61       || endbit < 0
  62       || endbit >= bitlength
  63       || endbit < startbit)
  64     __cause_ex1 ("rangefail", "__setbits", __LINE__);
  65
  66   if (bitlength <= SET_CHAR_SIZE)
  67     for (i = startbit; i <= endbit; i++)
  68       SET_BIT_IN_CHAR (*((SET_CHAR *)out), i);
  69   else if (bitlength <= SET_SHORT_SIZE)
  70     for (i = startbit; i <= endbit; i++)
  71       SET_BIT_IN_SHORT (*((SET_SHORT *)out), i);
  72   else
  73     {
  74       SET_WORD  *p;
  75       unsigned long       bitnr;
  76
  77       /* FIXME - this is inefficient! */
  78       for (i = startbit; i <= endbit; i++)
  79         {
  80           p = out + (i / SET_WORD_SIZE);
  81           bitnr = i % SET_WORD_SIZE;
  82           SET_BIT_IN_WORD (*p, bitnr);
  83         }
  84     }
  85 }