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(memchr) 10 RETGUARD_SETUP(memchr, r11) 11 movb %sil,%al /* set character to search for */ 12 movq %rdx,%rcx /* set length of search */ 13 testq %rcx,%rcx /* test for len == 0 */ 14 jz 1f 15 repne /* search! */ 16 scasb 17 jne 1f /* scan failed, return null */ 18 leaq -1(%rdi),%rax /* adjust result of scan */ 19 jmp 2f 201: xorq %rax,%rax 212: RETGUARD_CHECK(memchr, r11) 22 ret 23 lfence 24END(memchr) 25