1/* 2 * Written by J.T. Conklin <jtc@netbsd.org>. 3 * Public domain. 4 * Adapted for NetBSD/x86_64 by Frank van der Linden <fvdl@wasabisystems.com> 5 */ 6 7#include <machine/asm.h> 8 9ENTRY(ffs) 10 bsfl %edi,%eax 11 jz L1 /* ZF is set if all bits are 0 */ 12 incl %eax /* bits numbered from 1, not 0 */ 13 ret 14 15 _ALIGN_TEXT 16L1: xorl %eax,%eax /* clear result */ 17 ret 18