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/* ffs -- find first set bit in a word, counted from least significant end.
For Intel 80x86, x>=3.
This file is part of the GNU C Library.
Copyright (C) 1991-2024 Free Software Foundation, Inc.
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, see
<https://www.gnu.org/licenses/>. */
#define ffsl __something_else
#include <string.h>
#undef ffs
#ifdef __GNUC__
int
__ffs (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 1f\n" /* Jump if OK, i.e. X was non-zero. */
"leal 1(%1),%0\n" /* Return bsfl-result plus one on %0. */
"1:" : "=&a" (cnt), "=r" (tmp) : "rm" (x));
return cnt;
}
weak_alias (__ffs, ffs)
libc_hidden_def (__ffs)
libc_hidden_builtin_def (ffs)
#undef ffsl
weak_alias (__ffs, ffsl)
#else
#include <string/ffs.c>
#endif
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