1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * arch/openrisc/lib/memcpy.c
4 *
5 * Optimized memory copy routines for openrisc. These are mostly copied
6 * from ohter sources but slightly entended based on ideas discuassed in
7 * #openrisc.
8 *
9 * The word unroll implementation is an extension to the arm byte
10 * unrolled implementation, but using word copies (if things are
11 * properly aligned)
12 *
13 * The great arm loop unroll algorithm can be found at:
14 * arch/arm/boot/compressed/string.c
15 */
16
17 #include <linux/export.h>
18
19 #include <linux/string.h>
20
21 #ifdef CONFIG_OR1K_1200
22 /*
23 * Do memcpy with word copies and loop unrolling. This gives the
24 * best performance on the OR1200 and MOR1KX archirectures
25 */
26 void *memcpy(void *dest, __const void *src, __kernel_size_t n)
27 {
28 int i = 0;
29 unsigned char *d, *s;
30 uint32_t *dest_w = (uint32_t *)dest, *src_w = (uint32_t *)src;
31
32 /* If both source and dest are word aligned copy words */
33 if (!((unsigned int)dest_w & 3) && !((unsigned int)src_w & 3)) {
34 /* Copy 32 bytes per loop */
35 for (i = n >> 5; i > 0; i--) {
36 *dest_w++ = *src_w++;
37 *dest_w++ = *src_w++;
38 *dest_w++ = *src_w++;
39 *dest_w++ = *src_w++;
40 *dest_w++ = *src_w++;
41 *dest_w++ = *src_w++;
42 *dest_w++ = *src_w++;
43 *dest_w++ = *src_w++;
44 }
45
46 if (n & 1 << 4) {
47 *dest_w++ = *src_w++;
48 *dest_w++ = *src_w++;
49 *dest_w++ = *src_w++;
50 *dest_w++ = *src_w++;
51 }
52
53 if (n & 1 << 3) {
54 *dest_w++ = *src_w++;
55 *dest_w++ = *src_w++;
56 }
57
58 if (n & 1 << 2)
59 *dest_w++ = *src_w++;
60
61 d = (unsigned char *)dest_w;
62 s = (unsigned char *)src_w;
63
64 } else {
65 d = (unsigned char *)dest_w;
66 s = (unsigned char *)src_w;
67
68 for (i = n >> 3; i > 0; i--) {
69 *d++ = *s++;
70 *d++ = *s++;
71 *d++ = *s++;
72 *d++ = *s++;
73 *d++ = *s++;
74 *d++ = *s++;
75 *d++ = *s++;
76 *d++ = *s++;
77 }
78
79 if (n & 1 << 2) {
80 *d++ = *s++;
81 *d++ = *s++;
82 *d++ = *s++;
83 *d++ = *s++;
84 }
85 }
86
87 if (n & 1 << 1) {
88 *d++ = *s++;
89 *d++ = *s++;
90 }
91
92 if (n & 1)
93 *d++ = *s++;
94
95 return dest;
96 }
97 #else
98 /*
99 * Use word copies but no loop unrolling as we cannot assume there
100 * will be benefits on the archirecture
101 */
102 void *memcpy(void *dest, __const void *src, __kernel_size_t n)
103 {
104 unsigned char *d = (unsigned char *)dest, *s = (unsigned char *)src;
105 uint32_t *dest_w = (uint32_t *)dest, *src_w = (uint32_t *)src;
106
107 /* If both source and dest are word aligned copy words */
108 if (!((unsigned int)dest_w & 3) && !((unsigned int)src_w & 3)) {
109 for (; n >= 4; n -= 4)
110 *dest_w++ = *src_w++;
111 }
112
113 d = (unsigned char *)dest_w;
114 s = (unsigned char *)src_w;
115
116 /* For remaining or if not aligned, copy bytes */
117 for (; n >= 1; n -= 1)
118 *d++ = *s++;
119
120 return dest;
121
122 }
123 #endif
124
125 EXPORT_SYMBOL(memcpy);