1/* $OpenBSD: strlen.S,v 1.1 2004/01/28 01:44:45 mickey Exp $ */ 2/* 3 * Written by J.T. Conklin <jtc@netbsd.org>. 4 * Public domain. 5 * Adapted for NetBSD/x86_64 by Frank van der Linden <fvdl@wasabisystems.com> 6 */ 7 8#include <machine/asm.h> 9 10ENTRY(strlen) 11 cld /* set search forward */ 12 xorl %eax,%eax /* set search for null terminator */ 13 movq $-1,%rcx /* set search for lots of characters */ 14 repne /* search! */ 15 scasb 16 notq %rcx /* get length by taking complement */ 17 leaq -1(%rcx),%rax /* and subtracting one */ 18 ret 19