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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.
04277e02 4 Copyright (C) 1991-2019 Free Software Foundation, Inc.
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5 Contributed by Ulrich Drepper <drepper@cygnus.com>.
6
7 The GNU C Library is free software; you can redistribute it and/or
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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.
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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
41bdb6e2 15 Lesser General Public License for more details.
fed8f7f7 16
41bdb6e2 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/>. */
fed8f7f7 20
bdd421cc 21#define ffsl __something_else
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22#include <string.h>
23
24#undef ffs
25
26#ifdef __GNUC__
27
28int
bd2260a2 29__ffs (int x)
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30{
31 int cnt;
32 int tmp;
33
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));
37
38 return cnt + 1;
39}
40weak_alias (__ffs, ffs)
5bb43a43 41libc_hidden_def (__ffs)
2dd18ce2 42libc_hidden_builtin_def (ffs)
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43#undef ffsl
44weak_alias (__ffs, ffsl)
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45
46#else
2826ac7e 47#include <string/ffs.c>
fed8f7f7 48#endif