]>
git.ipfire.org Git - thirdparty/glibc.git/blob - sysdeps/i386/i686/ffs.c
1 /* ffs -- find first set bit in a word, counted from least significant end.
3 This file is part of the GNU C Library.
4 Copyright (C) 1991-2020 Free Software Foundation, Inc.
5 Contributed by Ulrich Drepper <drepper@cygnus.com>.
7 The GNU C Library is free software; you can redistribute it and/or
8 modify it under the terms of the GNU Lesser General Public
9 License as published by the Free Software Foundation; either
10 version 2.1 of the License, or (at your option) any later version.
12 The GNU C Library is distributed in the hope that it will be useful,
13 but WITHOUT ANY WARRANTY; without even the implied warranty of
14 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 Lesser General Public License for more details.
17 You should have received a copy of the GNU Lesser General Public
18 License along with the GNU C Library; if not, see
19 <https://www.gnu.org/licenses/>. */
21 #define ffsl __something_else
34 asm ("bsfl %2,%0\n" /* Count low bits in X and store in %1. */
35 "cmovel %1,%0\n" /* If number was zero, use -1 as result. */
36 : "=&r" (cnt
), "=r" (tmp
) : "rm" (x
), "1" (-1));
40 weak_alias (__ffs
, ffs
)
41 libc_hidden_def (__ffs
)
42 libc_hidden_builtin_def (ffs
)
44 weak_alias (__ffs
, ffsl
)
47 #include <string/ffs.c>