/*
 * 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(memchr)
        RETGUARD_SETUP(memchr, r11)
        movb    %sil,%al                /* set character to search for */
        movq    %rdx,%rcx               /* set length of search */
        testq   %rcx,%rcx               /* test for len == 0 */
        jz      1f
        repne                           /* search! */
        scasb
        jne     1f                      /* scan failed, return null */
        leaq    -1(%rdi),%rax           /* adjust result of scan */
        jmp     2f
1:      xorq    %rax,%rax
2:      RETGUARD_CHECK(memchr, r11)
        ret
        lfence
END(memchr)