/* ffs -- find first set bit in a word, counted from least significant end. For Intel 80x86, x>=3. Copyright (C) 1991, 1992, 1993, 1994 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 Library General Public License as published by the Free Software Foundation; either version 2 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 Library General Public License for more details. You should have received a copy of the GNU Library General Public License along with the GNU C Library; see the file COPYING.LIB. If not, write to the Free Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ #include #include #undef ffs #ifdef __GNUC__ #include "asm-ops.h" int DEFUN(ffs, (x), int x) { #if 0 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 " LF(1) "\n" /* Jump if OK, i.e. X was non-zero. */ "leal 1(%1),%0\n" /* Return bsfl-result plus one on %0. */ LL(1) : "=&a" (cnt), "=r" (tmp) : "rm" (x)); return cnt; #else return __builtin_ffs (x); #endif } #else #include #endif