2 * Written by J.T. Conklin <jtc@NetBSD.org>.
4 * Adapted for NetBSD/x86_64 by Frank van der Linden <fvdl@wasabisystems.com>
6 * $NetBSD: bzero.S,v 1.2 2003/07/26 19:24:38 salo Exp $
7 * $FreeBSD: src/lib/libc/amd64/string/bzero.S,v 1.3 2008/11/02 01:10:54 peter Exp $
10 #include <machine/asm.h>
13 cld /* set fill direction forward */
14 xorq %rax,%rax /* set fill data to 0 */
17 * if the string is too short, it's really not worth the overhead
18 * of aligning to word boundries, etc. So we jump to a plain
24 movq %rdi,%rcx /* compute misalignment */
28 rep /* zero until word aligned */
31 movq %rsi,%rcx /* zero by words */
37 L1: movq %rsi,%rcx /* zero remainder by bytes */