1/* ffsll -- find first set bit in a word, counted from least significant end.
2 For AMD x86-64.
3 This file is part of the GNU C Library.
4 Copyright (C) 1991-2023 Free Software Foundation, Inc.
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
10
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <https://www.gnu.org/licenses/>. */
19
20#define ffsl __something_else
21#include <string.h>
22
23#undef ffsll
24
25int
26ffsll (long long int x)
27{
28 long long int cnt;
29 long long int tmp;
30
31 asm ("bsfq %2,%0\n" /* Count low bits in X and store in %1. */
32 "cmoveq %1,%0\n" /* If number was zero, use -1 as result. */
33 : "=&r" (cnt), "=r" (tmp) : "rm" (x), "1" (-1));
34
35 return cnt + 1;
36}
37
38#ifndef __ILP32__
39#undef ffsl
40weak_alias (ffsll, ffsl)
41#endif
42