sysdeps/m68k/ffs.c

   1 /* ffs -- find first set bit in a word, counted from least significant end.
   2    For mc68020, mc68030, mc68040.
   3    This file is part of the GNU C Library.
   4    Copyright (C) 1991, 1992, 1997, 1998 Free Software Foundation, Inc.
   5    Contributed by Torbjorn Granlund (tege@sics.se).
   6
   7    The GNU C Library is free software; you can redistribute it and/or
   8    modify it under the terms of the GNU Lesser General Public
   9    License as published by the Free Software Foundation; either
  10    version 2.1 of the License, or (at your option) any later version.
  11
  12    The GNU C Library 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 GNU
  15    Lesser General Public License for more details.
  16
  17    You should have received a copy of the GNU Lesser General Public
  18    License along with the GNU C Library; if not, write to the Free
  19    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  20    02111-1307 USA.  */
  21
  22 #define ffsl __something_else
  23 #include <string.h>
  24
  25 #undef  ffs
  26
  27 #if     defined (__GNUC__) && defined (__mc68020__)
  28
  29 int
  30 __ffs (x)
  31      int x;
  32 {
  33   int cnt;
  34
  35   asm ("bfffo %1{#0:#0},%0" : "=d" (cnt) : "dm" (x & -x));
  36
  37   return 32 - cnt;
  38 }
  39 weak_alias (__ffs, ffs)
  40 #undef ffsl
  41 weak_alias (__ffs, ffsl)
  42
  43 #else
  44
  45 #include <sysdeps/generic/ffs.c>
  46
  47 #endif