1/* 2 * Written by J.T. Conklin <jtc@NetBSD.org>. 3 * Public domain. 4 */ 5 6#include <machine/asm.h> 7 8#if defined(LIBC_SCCS) 9 RCSID("$NetBSD: ffs.S,v 1.2 2014/03/22 19:38:46 jakllsch Exp $") 10#endif 11 12ENTRY(ffs) 13 bsfl 4(%esp),%eax 14 jz L1 /* ZF is set if all bits are 0 */ 15 incl %eax /* bits numbered from 1, not 0 */ 16 ret 17 18 _ALIGN_TEXT 19L1: xorl %eax,%eax /* clear result */ 20 ret 21END(ffs) 22