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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/types.h> |
28 | #include <linux/stddef.h> |
29 | #include <linux/compiler.h> |
30 | #include <linux/module.h> |
31 | |
32 | #include <linux/string.h> |
33 | #include <asm/system.h> |
34 | |
35 | #ifdef __HAVE_ARCH_MEMCPY |
36 | #ifndef CONFIG_OPT_LIB_FUNCTION |
37 | void *memcpy(void *v_dst, const void *v_src, __kernel_size_t c) |
38 | { |
39 | const char *src = v_src; |
40 | char *dst = v_dst; |
41 | |
42 | /* Simple, byte oriented memcpy. */ |
43 | while (c--) |
44 | *dst++ = *src++; |
45 | |
46 | return v_dst; |
47 | } |
48 | #else /* CONFIG_OPT_LIB_FUNCTION */ |
49 | void *memcpy(void *v_dst, const void *v_src, __kernel_size_t c) |
50 | { |
51 | const char *src = v_src; |
52 | char *dst = v_dst; |
53 | |
54 | /* The following code tries to optimize the copy by using unsigned |
55 | * alignment. This will work fine if both source and destination are |
56 | * aligned on the same boundary. However, if they are aligned on |
57 | * different boundaries shifts will be necessary. This might result in |
58 | * bad performance on MicroBlaze systems without a barrel shifter. |
59 | */ |
60 | const uint32_t *i_src; |
61 | uint32_t *i_dst; |
62 | |
63 | if (likely(c >= 4)) { |
64 | unsigned value, buf_hold; |
65 | |
66 | /* Align the dstination to a word boundry. */ |
67 | /* This is done in an endian independant manner. */ |
68 | switch ((unsigned long)dst & 3) { |
69 | case 1: |
70 | *dst++ = *src++; |
71 | --c; |
72 | case 2: |
73 | *dst++ = *src++; |
74 | --c; |
75 | case 3: |
76 | *dst++ = *src++; |
77 | --c; |
78 | } |
79 | |
80 | i_dst = (void *)dst; |
81 | |
82 | /* Choose a copy scheme based on the source */ |
83 | /* alignment relative to dstination. */ |
84 | switch ((unsigned long)src & 3) { |
85 | case 0x0: /* Both byte offsets are aligned */ |
86 | i_src = (const void *)src; |
87 | |
88 | for (; c >= 4; c -= 4) |
89 | *i_dst++ = *i_src++; |
90 | |
91 | src = (const void *)i_src; |
92 | break; |
93 | case 0x1: /* Unaligned - Off by 1 */ |
94 | /* Word align the source */ |
95 | i_src = (const void *) ((unsigned)src & ~3); |
96 | #ifndef __MICROBLAZEEL__ |
97 | /* Load the holding buffer */ |
98 | buf_hold = *i_src++ << 8; |
99 | |
100 | for (; c >= 4; c -= 4) { |
101 | value = *i_src++; |
102 | *i_dst++ = buf_hold | value >> 24; |
103 | buf_hold = value << 8; |
104 | } |
105 | #else |
106 | /* Load the holding buffer */ |
107 | buf_hold = (*i_src++ & 0xFFFFFF00) >>8; |
108 | |
109 | for (; c >= 4; c -= 4) { |
110 | value = *i_src++; |
111 | *i_dst++ = buf_hold | ((value & 0xFF) << 24); |
112 | buf_hold = (value & 0xFFFFFF00) >>8; |
113 | } |
114 | #endif |
115 | /* Realign the source */ |
116 | src = (const void *)i_src; |
117 | src -= 3; |
118 | break; |
119 | case 0x2: /* Unaligned - Off by 2 */ |
120 | /* Word align the source */ |
121 | i_src = (const void *) ((unsigned)src & ~3); |
122 | #ifndef __MICROBLAZEEL__ |
123 | /* Load the holding buffer */ |
124 | buf_hold = *i_src++ << 16; |
125 | |
126 | for (; c >= 4; c -= 4) { |
127 | value = *i_src++; |
128 | *i_dst++ = buf_hold | value >> 16; |
129 | buf_hold = value << 16; |
130 | } |
131 | #else |
132 | /* Load the holding buffer */ |
133 | buf_hold = (*i_src++ & 0xFFFF0000 )>>16; |
134 | |
135 | for (; c >= 4; c -= 4) { |
136 | value = *i_src++; |
137 | *i_dst++ = buf_hold | ((value & 0xFFFF)<<16); |
138 | buf_hold = (value & 0xFFFF0000) >>16; |
139 | } |
140 | #endif |
141 | /* Realign the source */ |
142 | src = (const void *)i_src; |
143 | src -= 2; |
144 | break; |
145 | case 0x3: /* Unaligned - Off by 3 */ |
146 | /* Word align the source */ |
147 | i_src = (const void *) ((unsigned)src & ~3); |
148 | #ifndef __MICROBLAZEEL__ |
149 | /* Load the holding buffer */ |
150 | buf_hold = *i_src++ << 24; |
151 | |
152 | for (; c >= 4; c -= 4) { |
153 | value = *i_src++; |
154 | *i_dst++ = buf_hold | value >> 8; |
155 | buf_hold = value << 24; |
156 | } |
157 | #else |
158 | /* Load the holding buffer */ |
159 | buf_hold = (*i_src++ & 0xFF000000) >> 24; |
160 | |
161 | for (; c >= 4; c -= 4) { |
162 | value = *i_src++; |
163 | *i_dst++ = buf_hold | ((value & 0xFFFFFF) << 8); |
164 | buf_hold = (value & 0xFF000000) >> 24; |
165 | } |
166 | #endif |
167 | /* Realign the source */ |
168 | src = (const void *)i_src; |
169 | src -= 1; |
170 | break; |
171 | } |
172 | dst = (void *)i_dst; |
173 | } |
174 | |
175 | /* Finish off any remaining bytes */ |
176 | /* simple fast copy, ... unless a cache boundry is crossed */ |
177 | switch (c) { |
178 | case 3: |
179 | *dst++ = *src++; |
180 | case 2: |
181 | *dst++ = *src++; |
182 | case 1: |
183 | *dst++ = *src++; |
184 | } |
185 | |
186 | return v_dst; |
187 | } |
188 | #endif /* CONFIG_OPT_LIB_FUNCTION */ |
189 | EXPORT_SYMBOL(memcpy); |
190 | #endif /* __HAVE_ARCH_MEMCPY */ |
191 |
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