minix/common/lib/libc/arch/x86_64/string/ffs.S

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ArmAsm
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/*
* 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>
#if defined(LIBC_SCCS)
RCSID("$NetBSD: ffs.S,v 1.4 2009/07/20 15:21:00 christos Exp $")
#endif
ENTRY(ffs)
bsfl %edi,%eax
jz 1f /* ZF is set if all bits are 0 */
incl %eax /* bits numbered from 1, not 0 */
ret
1: xorl %eax,%eax /* clear result */
ret