/*
 * 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>

ENTRY(ffs)
        RETGUARD_SETUP(ffs, r11)
        bsfl    %edi,%eax
        jz      1f                      /* ZF is set if all bits are 0 */
        incl    %eax                    /* bits numbered from 1, not 0 */
        jmp     2f

        _ALIGN_TRAPS
1:      xorl    %eax,%eax               /* clear result */
2:      RETGUARD_CHECK(ffs, r11)
        ret
        lfence
END(ffs)