/* ffs -- find first set bit in a word, counted from least significant end. For Intel 80x86, x>=3. This file is part of the GNU C Library. Copyright (C) 1991-2016 Free Software Foundation, Inc. Contributed by Torbjorn Granlund (tege@sics.se). The GNU C Library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. The GNU C Library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with the GNU C Library; if not, see . */ #define ffsl __something_else #include #undef ffs #ifdef __GNUC__ int __ffs (int x) { int cnt; int tmp; asm ("xorl %0,%0\n" /* Set CNT to zero. */ "bsfl %2,%1\n" /* Count low bits in X and store in %1. */ "jz 1f\n" /* Jump if OK, i.e. X was non-zero. */ "leal 1(%1),%0\n" /* Return bsfl-result plus one on %0. */ "1:" : "=&a" (cnt), "=r" (tmp) : "rm" (x)); return cnt; } weak_alias (__ffs, ffs) libc_hidden_def (__ffs) libc_hidden_builtin_def (ffs) #undef ffsl weak_alias (__ffs, ffsl) #else #include #endif