| /* $OpenBSD: ffs.S,v 1.1 2004/01/28 01:44:45 mickey Exp $ */ | |
| /* | |
| * Written by J.T. Conklin <jtc@netbsd.org>. | |
| * Public domain. | |
| * Adapted for NetBSD/x86_64 by Frank van der Linden <fvdl@wasabisystems.com> | |
| */ | |
| #include <machine/asm.h> | |
| ENTRY(ffs) | |
| bsfl %edi,%eax | |
| jz L1 /* ZF is set if all bits are 0 */ | |
| incl %eax /* bits numbered from 1, not 0 */ | |
| ret | |
| _ALIGN_TEXT | |
| L1: xorl %eax,%eax /* clear result */ | |
| ret |