xref: /minix3/common/lib/libc/arch/i386/string/ffs.S (revision 0a6a1f1d05b60e214de2f05a7310ddd1f0e590e7)
1b6cbf720SGianluca Guida/*
2b6cbf720SGianluca Guida * Written by J.T. Conklin <jtc@NetBSD.org>.
3b6cbf720SGianluca Guida * Public domain.
4b6cbf720SGianluca Guida */
5b6cbf720SGianluca Guida
6b6cbf720SGianluca Guida#include <machine/asm.h>
7b6cbf720SGianluca Guida
8b6cbf720SGianluca Guida#if defined(LIBC_SCCS)
9*0a6a1f1dSLionel Sambuc	RCSID("$NetBSD: ffs.S,v 1.2 2014/03/22 19:38:46 jakllsch Exp $")
10b6cbf720SGianluca Guida#endif
11b6cbf720SGianluca Guida
12b6cbf720SGianluca GuidaENTRY(ffs)
13b6cbf720SGianluca Guida	bsfl	4(%esp),%eax
14b6cbf720SGianluca Guida	jz	L1	 		/* ZF is set if all bits are 0 */
15b6cbf720SGianluca Guida	incl	%eax			/* bits numbered from 1, not 0 */
16b6cbf720SGianluca Guida	ret
17b6cbf720SGianluca Guida
18b6cbf720SGianluca Guida	_ALIGN_TEXT
19b6cbf720SGianluca GuidaL1:	xorl	%eax,%eax		/* clear result */
20b6cbf720SGianluca Guida	ret
21*0a6a1f1dSLionel SambucEND(ffs)
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