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 "DEFS.h" 8 9ENTRY(memchr) 10 movb %sil,%al /* set character to search for */ 11 movq %rdx,%rcx /* set length of search */ 12 testq %rcx,%rcx /* test for len == 0 */ 13 jz L1 14 cld /* set search forward */ 15 repne /* search! */ 16 scasb 17 jne L1 /* scan failed, return null */ 18 leaq -1(%rdi),%rax /* adjust result of scan */ 19 ret 20L1: xorq %rax,%rax 21 ret 22END_STRONG(memchr) 23