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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 Motorola 88000.
00003    This file is part of the GNU C Library.
00004    Copyright (C) 1991, 1992, 1997, 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 #include <bstring.h>
00023 
00024 #undef ffs
00025 
00026 #ifdef __GNUC__
00027 
00028 int
00029 __ffs (x)
00030      int x;
00031 {
00032   int cnt;
00033 
00034   if (x == 0)
00035     return 0;
00036 
00037   asm ("ff1 %0,%1" : "=r" (cnt) : "r" (x & -x));
00038   return cnt + 1;
00039 }
00040 weak_alias (__ffs, ffs)
00041 libc_hidden_builtin_def (ffs)
00042 
00043 #else
00044 #include <string/ffs.c>
00045 #endif