summaryrefslogtreecommitdiffstats
path: root/arch/s390/lib/mem.S
blob: 7ff79a4ff00cd9fae70d83f4674f6f8a01033967 (plain)
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
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
/*
 * String handling functions.
 *
 * Copyright IBM Corp. 2012
 */

#include <linux/linkage.h>
#include <asm/export.h>

/*
 * void *memmove(void *dest, const void *src, size_t n)
 */
ENTRY(memmove)
	ltgr	%r4,%r4
	lgr	%r1,%r2
	bzr	%r14
	aghi	%r4,-1
	clgr	%r2,%r3
	jnh	.Lmemmove_forward
	la	%r5,1(%r4,%r3)
	clgr	%r2,%r5
	jl	.Lmemmove_reverse
.Lmemmove_forward:
	srlg	%r0,%r4,8
	ltgr	%r0,%r0
	jz	.Lmemmove_forward_remainder
.Lmemmove_forward_loop:
	mvc	0(256,%r1),0(%r3)
	la	%r1,256(%r1)
	la	%r3,256(%r3)
	brctg	%r0,.Lmemmove_forward_loop
.Lmemmove_forward_remainder:
	larl	%r5,.Lmemmove_mvc
	ex	%r4,0(%r5)
	br	%r14
.Lmemmove_reverse:
	ic	%r0,0(%r4,%r3)
	stc	%r0,0(%r4,%r1)
	brctg	%r4,.Lmemmove_reverse
	ic	%r0,0(%r4,%r3)
	stc	%r0,0(%r4,%r1)
	br	%r14
.Lmemmove_mvc:
	mvc	0(1,%r1),0(%r3)
EXPORT_SYMBOL(memmove)

/*
 * memset implementation
 *
 * This code corresponds to the C construct below. We do distinguish
 * between clearing (c == 0) and setting a memory array (c != 0) simply
 * because nearly all memset invocations in the kernel clear memory and
 * the xc instruction is preferred in such cases.
 *
 * void *memset(void *s, int c, size_t n)
 * {
 *	if (likely(c == 0))
 *		return __builtin_memset(s, 0, n);
 *	return __builtin_memset(s, c, n);
 * }
 */
ENTRY(memset)
	ltgr	%r4,%r4
	bzr	%r14
	ltgr	%r3,%r3
	jnz	.Lmemset_fill
	aghi	%r4,-1
	srlg	%r3,%r4,8
	ltgr	%r3,%r3
	lgr	%r1,%r2
	jz	.Lmemset_clear_remainder
.Lmemset_clear_loop:
	xc	0(256,%r1),0(%r1)
	la	%r1,256(%r1)
	brctg	%r3,.Lmemset_clear_loop
.Lmemset_clear_remainder:
	larl	%r3,.Lmemset_xc
	ex	%r4,0(%r3)
	br	%r14
.Lmemset_fill:
	stc	%r3,0(%r2)
	cghi	%r4,1
	lgr	%r1,%r2
	ber	%r14
	aghi	%r4,-2
	srlg	%r3,%r4,8
	ltgr	%r3,%r3
	jz	.Lmemset_fill_remainder
.Lmemset_fill_loop:
	mvc	1(256,%r1),0(%r1)
	la	%r1,256(%r1)
	brctg	%r3,.Lmemset_fill_loop
.Lmemset_fill_remainder:
	larl	%r3,.Lmemset_mvc
	ex	%r4,0(%r3)
	br	%r14
.Lmemset_xc:
	xc	0(1,%r1),0(%r1)
.Lmemset_mvc:
	mvc	1(1,%r1),0(%r1)
EXPORT_SYMBOL(memset)

/*
 * memcpy implementation
 *
 * void *memcpy(void *dest, const void *src, size_t n)
 */
ENTRY(memcpy)
	ltgr	%r4,%r4
	bzr	%r14
	aghi	%r4,-1
	srlg	%r5,%r4,8
	ltgr	%r5,%r5
	lgr	%r1,%r2
	jnz	.Lmemcpy_loop
.Lmemcpy_remainder:
	larl	%r5,.Lmemcpy_mvc
	ex	%r4,0(%r5)
	br	%r14
.Lmemcpy_loop:
	mvc	0(256,%r1),0(%r3)
	la	%r1,256(%r1)
	la	%r3,256(%r3)
	brctg	%r5,.Lmemcpy_loop
	j	.Lmemcpy_remainder
.Lmemcpy_mvc:
	mvc	0(1,%r1),0(%r3)
EXPORT_SYMBOL(memcpy)