1/*	$OpenBSD: bzero.S,v 1.6 2022/08/22 09:33:40 jsg Exp $	*/
2
3/*
4 * Written by J.T. Conklin <jtc@netbsd.org>.
5 * Public domain.
6 */
7
8#include <machine/asm.h>
9
10ENTRY(bzero)
11	pushl	%edi
12	movl	8(%esp),%edi
13	movl	12(%esp),%edx
14
15	xorl	%eax,%eax		/* set fill data to 0 */
16
17	/*
18	 * if the string is too short, it's really not worth the overhead
19	 * of aligning to word boundaries, etc.  So we jump to a plain
20	 * unaligned set.
21	 */
22	cmpl	$16,%edx
23	jb	L1
24
25	movl	%edi,%ecx		/* compute misalignment */
26	negl	%ecx
27	andl	$3,%ecx
28	subl	%ecx,%edx
29	rep				/* zero until word aligned */
30	stosb
31
32	movl	%edx,%ecx		/* zero by words */
33	shrl	$2,%ecx
34	andl	$3,%edx
35	rep
36	stosl
37
38L1:	movl	%edx,%ecx		/* zero remainder by bytes */
39	rep
40	stosb
41
42	popl	%edi
43	ret
44