1 /* $OpenBSD: ffs.S,v 1.2 1996/09/27 06:47:45 mickey Exp $ */
2
3 /*
4 * Written by J.T. Conklin <jtc@netbsd.org>.
5 * Public domain.
6 */
7
8 #include <machine/asm.h>
9
10 ENTRY(ffs)
11 bsfl 4(%esp),%eax
12 jz L1 /* ZF is set if all bits are 0 */
13 incl %eax /* bits numbered from 1, not 0 */
14 ret
15
16 .align 2
17 L1: xorl %eax,%eax /* clear result */
18 ret