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) 1991-2017 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, see
  19    <http://www.gnu.org/licenses/>.  */
  20
  21 #define ffsl __something_else
  22 #include <string.h>
  23
  24 #undef  ffs
  25
  26 #if     defined (__GNUC__) && defined (__mc68020__)
  27
  28 int
  29 __ffs (int x)
  30 {
  31   int cnt;
  32
  33   asm ("bfffo %1{#0:#0},%0" : "=d" (cnt) : "dm" (x & -x));
  34
  35   return 32 - cnt;
  36 }
  37 weak_alias (__ffs, ffs)
  38 libc_hidden_def (__ffs)
  39 libc_hidden_builtin_def (ffs)
  40 #undef ffsl
  41 weak_alias (__ffs, ffsl)
  42
  43 #else
  44
  45 #include <string/ffs.c>
  46
  47 #endif