summaryrefslogtreecommitdiff
path: root/sys/lib/libkern/arch/i386/ffs.S
blob: cf4daaa7fbb579c72b52862e0399d084948f51b2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
/*
 * Written by J.T. Conklin <jtc@netbsd.org>.
 * Public domain.
 */

#include <machine/asm.h>

#if defined(LIBC_SCCS)
	RCSID("$NetBSD: ffs.S,v 1.5 1995/10/07 09:27:03 mycroft Exp $")
#endif

ENTRY(ffs)
	bsfl	4(%esp),%eax
	jz	L1	 		/* ZF is set if all bits are 0 */
	incl	%eax			/* bits numbered from 1, not 0 */
	ret

	.align 2
L1:	xorl	%eax,%eax		/* clear result */
	ret