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c9cf6dde AJ |
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. | |
d614a753 | 4 | Copyright (C) 1991-2020 Free Software Foundation, Inc. |
c9cf6dde AJ |
5 | Contributed by Ulrich Drepper <drepper@cygnus.com>. |
6 | ||
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. | |
11 | ||
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. | |
16 | ||
17 | You should have received a copy of the GNU Lesser General Public | |
59ba27a6 | 18 | License along with the GNU C Library; if not, see |
5a82c748 | 19 | <https://www.gnu.org/licenses/>. */ |
c9cf6dde AJ |
20 | |
21 | #define ffsl __something_else | |
22 | #include <string.h> | |
23 | ||
24 | #undef ffsll | |
25 | ||
26 | int | |
27 | ffsll (long long int x) | |
28 | { | |
29 | long long int cnt; | |
30 | long long int tmp; | |
31 | ||
32 | asm ("bsfq %2,%0\n" /* Count low bits in X and store in %1. */ | |
33 | "cmoveq %1,%0\n" /* If number was zero, use -1 as result. */ | |
34 | : "=&r" (cnt), "=r" (tmp) : "rm" (x), "1" (-1)); | |
35 | ||
36 | return cnt + 1; | |
37 | } | |
38 | ||
34a27407 | 39 | #ifndef __ILP32__ |
c9cf6dde AJ |
40 | #undef ffsl |
41 | weak_alias (ffsll, ffsl) | |
473c3ef3 | 42 | #endif |