/*      $OpenBSD: ffs.S,v 1.6 2018/07/03 23:14:05 mortimer 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 "DEFS.h"

ENTRY(ffs)
        RETGUARD_SETUP(ffs, r11)
        bsfl    %edi,%eax
        jz      L1                      /* ZF is set if all bits are 0 */
        incl    %eax                    /* bits numbered from 1, not 0 */
        jmp L2

        _ALIGN_TEXT
L1:     xorl    %eax,%eax               /* clear result */
L2:     RETGUARD_CHECK(ffs, r11)
        ret
END(ffs)
.protected ffs