1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
|
/*
* Written by J.T. Conklin <jtc@NetBSD.org>.
* Public domain.
* Adapted for NetBSD/x86_64 by Frank van der Linden <fvdl@wasabisystems.com>
*/
#include <machine/asm.h>
__FBSDID("$FreeBSD$");
#if 0
RCSID("$NetBSD: memset.S,v 1.3 2004/02/26 20:50:06 drochner Exp $")
#endif
ENTRY(memset)
movq %rsi,%rax
andq $0xff,%rax
movq %rdx,%rcx
movq %rdi,%r11
cld /* set fill direction forward */
/*
* if the string is too short, it's really not worth the overhead
* of aligning to word boundries, etc. So we jump to a plain
* unaligned set.
*/
cmpq $0x0f,%rcx
jle L1
movb %al,%ah /* copy char to all bytes in word */
movl %eax,%edx
sall $16,%eax
orl %edx,%eax
movl %eax,%edx
salq $32,%rax
orq %rdx,%rax
movq %rdi,%rdx /* compute misalignment */
negq %rdx
andq $7,%rdx
movq %rcx,%r8
subq %rdx,%r8
movq %rdx,%rcx /* set until word aligned */
rep
stosb
movq %r8,%rcx
shrq $3,%rcx /* set by words */
rep
stosq
movq %r8,%rcx /* set remainder by bytes */
andq $7,%rcx
L1: rep
stosb
movq %r11,%rax
ret
END(memset)
.section .note.GNU-stack,"",%progbits
|
