/* ffs -- find first set bit in a word, counted from least significant end.
For Intel 80x86, x>=3.
Copyright (C) 1991, 1992, 1993, 1994 Free Software Foundation, Inc.
Contributed by Torbjorn Granlund (tege@sics.se).
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, write to the Free Software Foundation, Inc., 675 Mass Ave,
Cambridge, MA 02139, USA. */
#include
#include
#undef ffs
#ifdef __GNUC__
int
DEFUN(ffs, (x), int x)
{
int cnt;
int tmp;
asm ("xorl %0,%0\n" /* Set CNT to zero. */
"bsfl %2,%1\n" /* Count low bits in X and store in %1. */
"jz nonzero\n" /* Jump if OK, i.e. X was non-zero. */
"leal 1(%1),%0\n" /* Return bsfl-result plus one on %0. */
"nonzero:" : "=&a" (cnt), "=r" (tmp) : "rm" (x));
return cnt;
}
#else
#include
#endif