1 | /* |
2 | * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu> |
3 | * Copyright (C) 2008-2009 PetaLogix |
4 | * Copyright (C) 2007 John Williams |
5 | * |
6 | * Reasonably optimised generic C-code for memcpy on Microblaze |
7 | * This is generic C code to do efficient, alignment-aware memcpy. |
8 | * |
9 | * It is based on demo code originally Copyright 2001 by Intel Corp, taken from |
10 | * http://www.embedded.com/showArticle.jhtml?articleID=19205567 |
11 | * |
12 | * Attempts were made, unsuccessfully, to contact the original |
13 | * author of this code (Michael Morrow, Intel). Below is the original |
14 | * copyright notice. |
15 | * |
16 | * This software has been developed by Intel Corporation. |
17 | * Intel specifically disclaims all warranties, express or |
18 | * implied, and all liability, including consequential and |
19 | * other indirect damages, for the use of this program, including |
20 | * liability for infringement of any proprietary rights, |
21 | * and including the warranties of merchantability and fitness |
22 | * for a particular purpose. Intel does not assume any |
23 | * responsibility for and errors which may appear in this program |
24 | * not any responsibility to update it. |
25 | */ |
26 | |
27 | #include <linux/export.h> |
28 | #include <linux/types.h> |
29 | #include <linux/stddef.h> |
30 | #include <linux/compiler.h> |
31 | |
32 | #include <linux/string.h> |
33 | |
34 | #ifdef CONFIG_OPT_LIB_FUNCTION |
35 | void *memcpy(void *v_dst, const void *v_src, __kernel_size_t c) |
36 | { |
37 | const char *src = v_src; |
38 | char *dst = v_dst; |
39 | |
40 | /* The following code tries to optimize the copy by using unsigned |
41 | * alignment. This will work fine if both source and destination are |
42 | * aligned on the same boundary. However, if they are aligned on |
43 | * different boundaries shifts will be necessary. This might result in |
44 | * bad performance on MicroBlaze systems without a barrel shifter. |
45 | */ |
46 | const uint32_t *i_src; |
47 | uint32_t *i_dst; |
48 | |
49 | if (likely(c >= 4)) { |
50 | unsigned value, buf_hold; |
51 | |
52 | /* Align the destination to a word boundary. */ |
53 | /* This is done in an endian independent manner. */ |
54 | switch ((unsigned long)dst & 3) { |
55 | case 1: |
56 | *dst++ = *src++; |
57 | --c; |
58 | fallthrough; |
59 | case 2: |
60 | *dst++ = *src++; |
61 | --c; |
62 | fallthrough; |
63 | case 3: |
64 | *dst++ = *src++; |
65 | --c; |
66 | } |
67 | |
68 | i_dst = (void *)dst; |
69 | |
70 | /* Choose a copy scheme based on the source */ |
71 | /* alignment relative to destination. */ |
72 | switch ((unsigned long)src & 3) { |
73 | case 0x0: /* Both byte offsets are aligned */ |
74 | i_src = (const void *)src; |
75 | |
76 | for (; c >= 4; c -= 4) |
77 | *i_dst++ = *i_src++; |
78 | |
79 | src = (const void *)i_src; |
80 | break; |
81 | case 0x1: /* Unaligned - Off by 1 */ |
82 | /* Word align the source */ |
83 | i_src = (const void *) ((unsigned)src & ~3); |
84 | #ifndef __MICROBLAZEEL__ |
85 | /* Load the holding buffer */ |
86 | buf_hold = *i_src++ << 8; |
87 | |
88 | for (; c >= 4; c -= 4) { |
89 | value = *i_src++; |
90 | *i_dst++ = buf_hold | value >> 24; |
91 | buf_hold = value << 8; |
92 | } |
93 | #else |
94 | /* Load the holding buffer */ |
95 | buf_hold = (*i_src++ & 0xFFFFFF00) >> 8; |
96 | |
97 | for (; c >= 4; c -= 4) { |
98 | value = *i_src++; |
99 | *i_dst++ = buf_hold | ((value & 0xFF) << 24); |
100 | buf_hold = (value & 0xFFFFFF00) >> 8; |
101 | } |
102 | #endif |
103 | /* Realign the source */ |
104 | src = (const void *)i_src; |
105 | src -= 3; |
106 | break; |
107 | case 0x2: /* Unaligned - Off by 2 */ |
108 | /* Word align the source */ |
109 | i_src = (const void *) ((unsigned)src & ~3); |
110 | #ifndef __MICROBLAZEEL__ |
111 | /* Load the holding buffer */ |
112 | buf_hold = *i_src++ << 16; |
113 | |
114 | for (; c >= 4; c -= 4) { |
115 | value = *i_src++; |
116 | *i_dst++ = buf_hold | value >> 16; |
117 | buf_hold = value << 16; |
118 | } |
119 | #else |
120 | /* Load the holding buffer */ |
121 | buf_hold = (*i_src++ & 0xFFFF0000) >> 16; |
122 | |
123 | for (; c >= 4; c -= 4) { |
124 | value = *i_src++; |
125 | *i_dst++ = buf_hold | ((value & 0xFFFF) << 16); |
126 | buf_hold = (value & 0xFFFF0000) >> 16; |
127 | } |
128 | #endif |
129 | /* Realign the source */ |
130 | src = (const void *)i_src; |
131 | src -= 2; |
132 | break; |
133 | case 0x3: /* Unaligned - Off by 3 */ |
134 | /* Word align the source */ |
135 | i_src = (const void *) ((unsigned)src & ~3); |
136 | #ifndef __MICROBLAZEEL__ |
137 | /* Load the holding buffer */ |
138 | buf_hold = *i_src++ << 24; |
139 | |
140 | for (; c >= 4; c -= 4) { |
141 | value = *i_src++; |
142 | *i_dst++ = buf_hold | value >> 8; |
143 | buf_hold = value << 24; |
144 | } |
145 | #else |
146 | /* Load the holding buffer */ |
147 | buf_hold = (*i_src++ & 0xFF000000) >> 24; |
148 | |
149 | for (; c >= 4; c -= 4) { |
150 | value = *i_src++; |
151 | *i_dst++ = buf_hold | ((value & 0xFFFFFF) << 8); |
152 | buf_hold = (value & 0xFF000000) >> 24; |
153 | } |
154 | #endif |
155 | /* Realign the source */ |
156 | src = (const void *)i_src; |
157 | src -= 1; |
158 | break; |
159 | } |
160 | dst = (void *)i_dst; |
161 | } |
162 | |
163 | /* Finish off any remaining bytes */ |
164 | /* simple fast copy, ... unless a cache boundary is crossed */ |
165 | switch (c) { |
166 | case 3: |
167 | *dst++ = *src++; |
168 | fallthrough; |
169 | case 2: |
170 | *dst++ = *src++; |
171 | fallthrough; |
172 | case 1: |
173 | *dst++ = *src++; |
174 | } |
175 | |
176 | return v_dst; |
177 | } |
178 | EXPORT_SYMBOL(memcpy); |
179 | #endif /* CONFIG_OPT_LIB_FUNCTION */ |
180 | |