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fed8f7f7 UD |
1 | /* ffs -- find first set bit in a word, counted from least significant end. |
2 | For Intel 80x86, x>=6. | |
3 | This file is part of the GNU C Library. | |
4 | Copyright (C) 1991, 92, 93, 94, 97, 98 Free Software Foundation, Inc. | |
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 Library General Public License as | |
9 | published by the Free Software Foundation; either version 2 of the | |
10 | 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 | Library General Public License for more details. | |
16 | ||
17 | You should have received a copy of the GNU Library General Public | |
18 | License along with the GNU C Library; see the file COPYING.LIB. If not, | |
19 | write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
20 | Boston, MA 02111-1307, USA. */ | |
21 | ||
bdd421cc | 22 | #define ffsl __something_else |
fed8f7f7 UD |
23 | #include <string.h> |
24 | ||
25 | #undef ffs | |
26 | ||
27 | #ifdef __GNUC__ | |
28 | ||
29 | int | |
30 | __ffs (x) | |
31 | int x; | |
32 | { | |
33 | int cnt; | |
34 | int tmp; | |
35 | ||
36 | asm ("bsfl %2,%0\n" /* Count low bits in X and store in %1. */ | |
37 | "cmovel %1,%0\n" /* If number was zero, use -1 as result. */ | |
38 | : "=&r" (cnt), "=r" (tmp) : "rm" (x), "1" (-1)); | |
39 | ||
40 | return cnt + 1; | |
41 | } | |
42 | weak_alias (__ffs, ffs) | |
bdd421cc UD |
43 | #undef ffsl |
44 | weak_alias (__ffs, ffsl) | |
fed8f7f7 UD |
45 | |
46 | #else | |
47 | #include <sysdeps/generic/ffs.c> | |
48 | #endif |