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1/* ----------------------------------------------------------------------- *
2 *
3 *   Copyright 2008 H. Peter Anvin - All Rights Reserved
4 *
5 *   Permission is hereby granted, free of charge, to any person
6 *   obtaining a copy of this software and associated documentation
7 *   files (the "Software"), to deal in the Software without
8 *   restriction, including without limitation the rights to use,
9 *   copy, modify, merge, publish, distribute, sublicense, and/or
10 *   sell copies of the Software, and to permit persons to whom
11 *   the Software is furnished to do so, subject to the following
12 *   conditions:
13 *
14 *   The above copyright notice and this permission notice shall
15 *   be included in all copies or substantial portions of the Software.
16 *
17 *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
18 *   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
19 *   OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
20 *   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
21 *   HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
22 *   WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
23 *   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
24 *   OTHER DEALINGS IN THE SOFTWARE.
25 *
26 * ----------------------------------------------------------------------- */
27
28/*
29 * mempcpy.S
30 *
31 * Reasonably efficient mempcpy, using aligned transfers at least
32 * for the destination operand.
33 */
34
35	.text
36	.globl	mempcpy
37	.type	mempcpy, @function
38mempcpy:
39	movl	0xc(%esp),%ecx
40	movl	0x8(%esp),%edx
41	movl	0x4(%esp),%eax
42
43	jecxz	1f
44
45	pushl	%esi
46	pushl	%edi
47
48	movl	%eax,%edi
49	movl	%edx,%esi
50
51	/* Initial alignment */
52	movl	%edi,%edx
53	shrl	$1,%edx
54	jnc	11f
55	movsb
56	decl	%ecx
5711:
58	movb	%cl,%al
59	cmpl	$2,%ecx
60	jb	13f
61
62	shrl	$1,%edx
63	jnc	12f
64	movsw
65	subl	$2,%ecx
6612:
67	/* Bulk transfer */
68	movb	%cl,%al
69	shrl	$2,%ecx
70	rep; movsl
71
72	/* Final alignment */
73	testb	$2,%al
74	jz	14f
75	movsw
7613:
7714:
78	testb	$1,%al
79	jz	15f
80	movsb
8115:
82
83	movl	%edi,%eax	/* Return value */
84	popl	%edi
85	popl	%esi
861:
87	ret
88
89	.size	mempcpy, .-mempcpy
90