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 /* As a special exception, if you link this library with other files,
  22    some of which are compiled with GCC, to produce an executable,
  23    this library does not by itself cause the resulting executable
  24    to be covered by the GNU General Public License.
  25    This exception does not however invalidate any other reasons why
  26    the executable file might be covered by the GNU General Public License.  */
  27
  28 #define __CHILL_LIB__
  29
  30 #include <stdio.h>
  31 #include "powerset.h"
  32
  33 extern void __cause_ex1 (char *exname, char *file, int lineno);
  34
  35 /*
  36  * function __setbits
  37  *
  38  * parameters:
  39  *      out             result
  40  *      bitlength       length of bitstring in bits
  41  *      startbit        starting bitnumber
  42  *      endbit          ending bitnumber
  43  *
  44  * returns:
  45  *      void
  46  *
  47  * exceptions:
  48  *   rangefail
  49  *
  50  * abstract:
  51  *  set all bits from starting bitnumber to ending bitnumber
  52  *  in a powerset
  53  *
  54  */
  55 void
  56 __setbits (out, bitlength, startbit, endbit)
  57      SET_WORD      *out;
  58      unsigned long  bitlength;
  59      long  startbit;
  60      long  endbit;
  61 {
  62   unsigned long i;
  63
  64   if (out == NULL
  65       || startbit < 0
  66       || startbit >= bitlength
  67       || endbit < 0
  68       || endbit >= bitlength
  69       || endbit < startbit)
  70     __cause_ex1 ("rangefail", "__setbits", __LINE__);
  71
  72   if (bitlength <= SET_CHAR_SIZE)
  73     for (i = startbit; i <= endbit; i++)
  74       SET_BIT_IN_CHAR (*((SET_CHAR *)out), i);
  75   else if (bitlength <= SET_SHORT_SIZE)
  76     for (i = startbit; i <= endbit; i++)
  77       SET_BIT_IN_SHORT (*((SET_SHORT *)out), i);
  78   else
  79     {
  80       SET_WORD  *p;
  81       unsigned long       bitnr;
  82
  83       /* FIXME - this is inefficient! */
  84       for (i = startbit; i <= endbit; i++)
  85         {
  86           p = out + (i / SET_WORD_SIZE);
  87           bitnr = i % SET_WORD_SIZE;
  88           SET_BIT_IN_WORD (*p, bitnr);
  89         }
  90     }
  91 }