mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-18 19:10:06 +00:00
42 lines
1.4 KiB
C
42 lines
1.4 KiB
C
|
/* ffsll -- 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 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. */
|
||
|
|
|
||
|
|
#define ffsl __something_else
|
||
|
|
#include <string.h>
|
||
|
|
|
||
|
|
#undef ffsll
|
||
|
|
|
||
|
|
int
|
||
|
|
ffsll (long long int x)
|
||
|
|
{
|
||
|
|
long long int cnt;
|
||
|
|
long long int tmp;
|
||
|
|
|
||
|
|
asm ("bsfq %2,%0\n" /* Count low bits in X and store in %1. */
|
||
|
|
"cmoveq %1,%0\n" /* If number was zero, use -1 as result. */
|
||
|
|
: "=&r" (cnt), "=r" (tmp) : "rm" (x), "1" (-1));
|
||
|
|
|
||
|
|
return cnt + 1;
|
||
|
|
}
|
||
|
|
|
||
|
|
#undef ffsl
|
||
|
|
weak_alias (ffsll, ffsl)
|