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glibc  2.9
ffs.c
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00001 /* ffs -- find first set bit in a word, counted from least significant end.
00002    For mc68020, mc68030, mc68040.
00003    This file is part of the GNU C Library.
00004    Copyright (C) 1991, 1992, 1997, 1998, 2004, 2005 Free Software Foundation, Inc.
00005    Contributed by Torbjorn Granlund (tege@sics.se).
00006 
00007    The GNU C Library is free software; you can redistribute it and/or
00008    modify it under the terms of the GNU Lesser General Public
00009    License as published by the Free Software Foundation; either
00010    version 2.1 of the License, or (at your option) any later version.
00011 
00012    The GNU C Library is distributed in the hope that it will be useful,
00013    but WITHOUT ANY WARRANTY; without even the implied warranty of
00014    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015    Lesser General Public License for more details.
00016 
00017    You should have received a copy of the GNU Lesser General Public
00018    License along with the GNU C Library; if not, write to the Free
00019    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00020    02111-1307 USA.  */
00021 
00022 #define ffsl __something_else
00023 #include <string.h>
00024 
00025 #undef ffs
00026 
00027 #if    defined (__GNUC__) && defined (__mc68020__)
00028 
00029 int
00030 __ffs (x)
00031      int x;
00032 {
00033   int cnt;
00034 
00035   asm ("bfffo %1{#0:#0},%0" : "=d" (cnt) : "dm" (x & -x));
00036 
00037   return 32 - cnt;
00038 }
00039 weak_alias (__ffs, ffs)
00040 libc_hidden_builtin_def (ffs)
00041 #undef ffsl
00042 weak_alias (__ffs, ffsl)
00043 
00044 #else
00045 
00046 #include <string/ffs.c>
00047 
00048 #endif