glibc/sysdeps/x86_64/ffs.c
Ulrich Drepper 2dd18ce2b2 Update.
* include/string.h (ffs): Add libc_hidden_builtin_proto.
	* sysdeps/rs6000/ffs.c (ffs): Add libc_hidden_builtin_def.
	* sysdeps/alpha/alphaev67/ffs.S (ffs): Likewise.
	* sysdeps/alpha/ffs.S (ffs): Likewise.
	* sysdeps/s390/ffs.c (ffs): Likewise.
	* sysdeps/powerpc/ffs.c (ffs): Likewise.
	* sysdeps/i386/ffs.c (ffs): Likewise.
	* sysdeps/i386/i686/ffs.c (ffs): Likewise.
	* sysdeps/m68k/ffs.c (ffs): Likewise.
	* sysdeps/generic/ffs.c (ffs): Likewise.
	* sysdeps/m88k/ffs.c (ffs): Likewise.
	* sysdeps/am29k/ffs.c (ffs): Likewise.
	* sysdeps/i960/ffs.c (ffs): Likewise.
	* sysdeps/x86_64/ffs.c (ffs): Likewise.

	* Makerules (check-abi): Use diff -p -U 0 instead of diff -pu0.
2004-07-05 17:36:34 +00:00

40 lines
1.3 KiB
C

/* ffs -- find first set bit in a word, counted from least significant end.
For AMD x86-64.
This file is part of the GNU C Library.
Copyright (C) 1991,92,93,94,97,98,2001,2004 Free Software Foundation, Inc.
Contributed by Ulrich Drepper <drepper@cygnus.com>.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <string.h>
#undef ffs
int
__ffs (int x)
{
int cnt;
int tmp;
asm ("bsfl %2,%0\n" /* Count low bits in X and store in %1. */
"cmovel %1,%0\n" /* If number was zero, use -1 as result. */
: "=&r" (cnt), "=r" (tmp) : "rm" (x), "1" (-1));
return cnt + 1;
}
weak_alias (__ffs, ffs)
libc_hidden_builtin_def (ffs)