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git.ipfire.org Git - thirdparty/glibc.git/blob - sysdeps/x86_64/ffsll.c
1 /* ffsll -- find first set bit in a word, counted from least significant end.
3 This file is part of the GNU C Library.
4 Copyright (C) 1991-2024 Free Software Foundation, Inc.
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.
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.
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/>. */
20 #define ffsl __something_else
26 ffsll (long long int x
)
30 asm ("mov $-1,%k0\n" /* Initialize cnt to -1. */
31 "bsf %1,%0\n" /* Count low bits in x and store in cnt. */
32 "inc %k0\n" /* Increment cnt by 1. */
33 : "=&r" (cnt
) : "r" (x
));
40 weak_alias (ffsll
, ffsl
)