| Elliott Hughes | 8ca530e | 2013-10-17 17:03:22 -0700 | [diff] [blame] | 1 | /* $OpenBSD: ffs.S,v 1.1 2004/01/28 01:44:45 mickey Exp $ */ |
| 2 | /* | ||||
| 3 | * Written by J.T. Conklin <jtc@netbsd.org>. | ||||
| 4 | * Public domain. | ||||
| 5 | * Adapted for NetBSD/x86_64 by Frank van der Linden <fvdl@wasabisystems.com> | ||||
| 6 | */ | ||||
| 7 | |||||
| 8 | #include <machine/asm.h> | ||||
| 9 | |||||
| 10 | ENTRY(ffs) | ||||
| 11 | bsfl %edi,%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_TEXT | ||||
| 17 | L1: xorl %eax,%eax /* clear result */ | ||||
| 18 | ret | ||||