xref: /titanic_50/usr/src/lib/libc/i386/gen/memset.s (revision 142c9f13e148d687426ed2d4e8bd93717eeaebbc)
1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License, Version 1.0 only
6 * (the "License").  You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22/*
23 * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
24 * Use is subject to license terms.
25 */
26
27	.ident	"%Z%%M%	%I%	%E% SMI"
28
29	.file	"%M%"
30
31#include <sys/asm_linkage.h>
32
33	ANSI_PRAGMA_WEAK(memset,function)
34
35#include "SYS.h"
36
37	ANSI_PRAGMA_WEAK2(_private_memset,memset,function)
38
39	ENTRY(memset)
40	pushl	%edi		/ save register variable
41	movl	8(%esp),%edi	/ %edi = string address
42	movl	12(%esp),%eax	/ %al = byte to duplicate
43	movl	16(%esp),%ecx	/ %ecx = number of copies
44	cmpl	$20,%ecx	/ strings with 20 or more chars should
45	jbe	.byteset	/ byteset one word at a time
46.wordset:
47	andl	$0xff,%eax	/ Duplicate fill const 4 times in %eax
48	shrl	$2,%ecx		/ %ecx = number of words to set
49	movl	%eax,%edx
50	shll	$8,%eax		/ This is ugly, but no P6 partial stalls
51	orl	%edx,%eax	/ get introduced as before
52	shll	$8,%eax
53	orl	%edx,%eax
54	shll	$8,%eax
55	orl	%edx,%eax
56	rep; sstol
57	movl	16(%esp),%ecx
58	andl	$3,%ecx		/ %ecx = number of bytes left
59.byteset:
60	rep; sstob
61	movl	8(%esp),%eax	/ return string address
62	popl	%edi		/ restore register variable
63	ret
64	SET_SIZE(memset)
65