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 */
26void *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 */
102void *memcpy(void *dest, __const void *src, __kernel_size_t n)
103{
104	unsigned char *d, *s;
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
125EXPORT_SYMBOL(memcpy);
126