| /* 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) 1991-2014 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, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #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_def (__ffs) |
| libc_hidden_builtin_def (ffs) |
