1/* memset/bzero -- set memory area to CH/0
2   Highly optimized version for ix86, x>=6.
3   Copyright (C) 1999-2022 Free Software Foundation, Inc.
4   This file is part of the GNU C Library.
5
6   The GNU C Library is free software; you can redistribute it and/or
7   modify it under the terms of the GNU Lesser General Public
8   License as published by the Free Software Foundation; either
9   version 2.1 of the License, or (at your option) any later version.
10
11   The GNU C Library is distributed in the hope that it will be useful,
12   but WITHOUT ANY WARRANTY; without even the implied warranty of
13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14   Lesser General Public License for more details.
15
16   You should have received a copy of the GNU Lesser General Public
17   License along with the GNU C Library; if not, see
18   <https://www.gnu.org/licenses/>.  */
19
20#include <sysdep.h>
21#include "asm-syntax.h"
22
23#define PARMS	4+4	/* space for 1 saved reg */
24#define RTN	PARMS
25#define DEST	RTN
26#define CHR	DEST+4
27#define LEN	CHR+4
28
29        .text
30#if defined SHARED && IS_IN (libc)
31ENTRY_CHK (__memset_chk)
32	movl	12(%esp), %eax
33	cmpl	%eax, 16(%esp)
34	jb	HIDDEN_JUMPTARGET (__chk_fail)
35END_CHK (__memset_chk)
36#endif
37ENTRY (memset)
38
39	cld
40	pushl	%edi
41	cfi_adjust_cfa_offset (4)
42	movl	DEST(%esp), %edx
43	movl	LEN(%esp), %ecx
44	movzbl	CHR(%esp), %eax
45	jecxz	1f
46	movl	%edx, %edi
47	cfi_rel_offset (edi, 0)
48	andl	$3, %edx
49	jz	2f	/* aligned */
50	jp	3f	/* misaligned at 3, store just one byte below */
51	stosb		/* misaligned at 1 or 2, store two bytes */
52	decl	%ecx
53	jz	1f
543:	stosb
55	decl	%ecx
56	jz	1f
57	xorl	$1, %edx
58	jnz	2f	/* was misaligned at 2 or 3, now aligned */
59	stosb		/* was misaligned at 1, store third byte */
60	decl	%ecx
612:	movl	%ecx, %edx
62	shrl	$2, %ecx
63	andl	$3, %edx
64	imul	$0x01010101, %eax
65	rep
66	stosl
67	movl	%edx, %ecx
68	rep
69	stosb
70
711:
72	movl DEST(%esp), %eax	/* start address of destination is result */
73	popl	%edi
74	cfi_adjust_cfa_offset (-4)
75	cfi_restore (edi)
76
77	ret
78END (memset)
79libc_hidden_builtin_def (memset)
80