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
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
|
// SPDX-License-Identifier: GPL-2.0
/*
* linux/arch/alpha/lib/memcpy.c
*
* Copyright (C) 1995 Linus Torvalds
*/
/*
* This is a reasonably optimized memcpy() routine.
*/
/*
* Note that the C code is written to be optimized into good assembly. However,
* at this point gcc is unable to sanely compile "if (n >= 0)", resulting in a
* explicit compare against 0 (instead of just using the proper "blt reg, xx" or
* "bge reg, xx"). I hope alpha-gcc will be fixed to notice this eventually..
*/
#include <linux/types.h>
#include <linux/export.h>
/*
* This should be done in one go with ldq_u*2/mask/stq_u. Do it
* with a macro so that we can fix it up later..
*/
#define ALIGN_DEST_TO8_UP(d,s,n) \
while (d & 7) { \
if (n <= 0) return; \
n--; \
*(char *) d = *(char *) s; \
d++; s++; \
}
#define ALIGN_DEST_TO8_DN(d,s,n) \
while (d & 7) { \
if (n <= 0) return; \
n--; \
d--; s--; \
*(char *) d = *(char *) s; \
}
/*
* This should similarly be done with ldq_u*2/mask/stq. The destination
* is aligned, but we don't fill in a full quad-word
*/
#define DO_REST_UP(d,s,n) \
while (n > 0) { \
n--; \
*(char *) d = *(char *) s; \
d++; s++; \
}
#define DO_REST_DN(d,s,n) \
while (n > 0) { \
n--; \
d--; s--; \
*(char *) d = *(char *) s; \
}
/*
* This should be done with ldq/mask/stq. The source and destination are
* aligned, but we don't fill in a full quad-word
*/
#define DO_REST_ALIGNED_UP(d,s,n) DO_REST_UP(d,s,n)
#define DO_REST_ALIGNED_DN(d,s,n) DO_REST_DN(d,s,n)
/*
* This does unaligned memory copies. We want to avoid storing to
* an unaligned address, as that would do a read-modify-write cycle.
* We also want to avoid double-reading the unaligned reads.
*
* Note the ordering to try to avoid load (and address generation) latencies.
*/
static inline void __memcpy_unaligned_up (unsigned long d, unsigned long s,
long n)
{
ALIGN_DEST_TO8_UP(d,s,n);
n -= 8; /* to avoid compare against 8 in the loop */
if (n >= 0) {
unsigned long low_word, high_word;
__asm__("ldq_u %0,%1":"=r" (low_word):"m" (*(unsigned long *) s));
do {
unsigned long tmp;
__asm__("ldq_u %0,%1":"=r" (high_word):"m" (*(unsigned long *)(s+8)));
n -= 8;
__asm__("extql %1,%2,%0"
:"=r" (low_word)
:"r" (low_word), "r" (s));
__asm__("extqh %1,%2,%0"
:"=r" (tmp)
:"r" (high_word), "r" (s));
s += 8;
*(unsigned long *) d = low_word | tmp;
d += 8;
low_word = high_word;
} while (n >= 0);
}
n += 8;
DO_REST_UP(d,s,n);
}
static inline void __memcpy_unaligned_dn (unsigned long d, unsigned long s,
long n)
{
/* I don't understand AXP assembler well enough for this. -Tim */
s += n;
d += n;
while (n--)
* (char *) --d = * (char *) --s;
}
/*
* Hmm.. Strange. The __asm__ here is there to make gcc use an integer register
* for the load-store. I don't know why, but it would seem that using a floating
* point register for the move seems to slow things down (very small difference,
* though).
*
* Note the ordering to try to avoid load (and address generation) latencies.
*/
static inline void __memcpy_aligned_up (unsigned long d, unsigned long s,
long n)
{
ALIGN_DEST_TO8_UP(d,s,n);
n -= 8;
while (n >= 0) {
unsigned long tmp;
__asm__("ldq %0,%1":"=r" (tmp):"m" (*(unsigned long *) s));
n -= 8;
s += 8;
*(unsigned long *) d = tmp;
d += 8;
}
n += 8;
DO_REST_ALIGNED_UP(d,s,n);
}
static inline void __memcpy_aligned_dn (unsigned long d, unsigned long s,
long n)
{
s += n;
d += n;
ALIGN_DEST_TO8_DN(d,s,n);
n -= 8;
while (n >= 0) {
unsigned long tmp;
s -= 8;
__asm__("ldq %0,%1":"=r" (tmp):"m" (*(unsigned long *) s));
n -= 8;
d -= 8;
*(unsigned long *) d = tmp;
}
n += 8;
DO_REST_ALIGNED_DN(d,s,n);
}
void * memcpy(void * dest, const void *src, size_t n)
{
if (!(((unsigned long) dest ^ (unsigned long) src) & 7)) {
__memcpy_aligned_up ((unsigned long) dest, (unsigned long) src,
n);
return dest;
}
__memcpy_unaligned_up ((unsigned long) dest, (unsigned long) src, n);
return dest;
}
EXPORT_SYMBOL(memcpy);
|
