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1 | /* |
2 | * Copyright (C) 2013 ARM Ltd. | |
3 | * Copyright (C) 2013 Linaro. | |
4 | * | |
5 | * This code is based on glibc cortex strings work originally authored by Linaro | |
6 | * and re-licensed under GPLv2 for the Linux kernel. The original code can | |
7 | * be found @ | |
8 | * | |
9 | * http://bazaar.launchpad.net/~linaro-toolchain-dev/cortex-strings/trunk/ | |
10 | * files/head:/src/aarch64/ | |
11 | * | |
12 | * This program is free software; you can redistribute it and/or modify | |
13 | * it under the terms of the GNU General Public License version 2 as | |
14 | * published by the Free Software Foundation. | |
15 | * | |
16 | * This program is distributed in the hope that it will be useful, | |
17 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
18 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
19 | * GNU General Public License for more details. | |
20 | * | |
21 | * You should have received a copy of the GNU General Public License | |
22 | * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
23 | */ | |
24 | ||
25 | ||
26 | /* | |
27 | * Copy a buffer from src to dest (alignment handled by the hardware) | |
28 | * | |
29 | * Parameters: | |
30 | * x0 - dest | |
31 | * x1 - src | |
32 | * x2 - n | |
33 | * Returns: | |
34 | * x0 - dest | |
35 | */ | |
36 | dstin .req x0 | |
37 | src .req x1 | |
38 | count .req x2 | |
39 | tmp1 .req x3 | |
40 | tmp1w .req w3 | |
41 | tmp2 .req x4 | |
42 | tmp2w .req w4 | |
43 | dst .req x6 | |
44 | ||
45 | A_l .req x7 | |
46 | A_h .req x8 | |
47 | B_l .req x9 | |
48 | B_h .req x10 | |
49 | C_l .req x11 | |
50 | C_h .req x12 | |
51 | D_l .req x13 | |
52 | D_h .req x14 | |
53 | ||
54 | mov dst, dstin | |
55 | cmp count, #16 | |
56 | /*When memory length is less than 16, the accessed are not aligned.*/ | |
57 | b.lo .Ltiny15 | |
58 | ||
59 | neg tmp2, src | |
60 | ands tmp2, tmp2, #15/* Bytes to reach alignment. */ | |
61 | b.eq .LSrcAligned | |
62 | sub count, count, tmp2 | |
63 | /* | |
64 | * Copy the leading memory data from src to dst in an increasing | |
65 | * address order.By this way,the risk of overwritting the source | |
66 | * memory data is eliminated when the distance between src and | |
67 | * dst is less than 16. The memory accesses here are alignment. | |
68 | */ | |
69 | tbz tmp2, #0, 1f | |
70 | ldrb1 tmp1w, src, #1 | |
71 | strb1 tmp1w, dst, #1 | |
72 | 1: | |
73 | tbz tmp2, #1, 2f | |
74 | ldrh1 tmp1w, src, #2 | |
75 | strh1 tmp1w, dst, #2 | |
76 | 2: | |
77 | tbz tmp2, #2, 3f | |
78 | ldr1 tmp1w, src, #4 | |
79 | str1 tmp1w, dst, #4 | |
80 | 3: | |
81 | tbz tmp2, #3, .LSrcAligned | |
82 | ldr1 tmp1, src, #8 | |
83 | str1 tmp1, dst, #8 | |
84 | ||
85 | .LSrcAligned: | |
86 | cmp count, #64 | |
87 | b.ge .Lcpy_over64 | |
88 | /* | |
89 | * Deal with small copies quickly by dropping straight into the | |
90 | * exit block. | |
91 | */ | |
92 | .Ltail63: | |
93 | /* | |
94 | * Copy up to 48 bytes of data. At this point we only need the | |
95 | * bottom 6 bits of count to be accurate. | |
96 | */ | |
97 | ands tmp1, count, #0x30 | |
98 | b.eq .Ltiny15 | |
99 | cmp tmp1w, #0x20 | |
100 | b.eq 1f | |
101 | b.lt 2f | |
102 | ldp1 A_l, A_h, src, #16 | |
103 | stp1 A_l, A_h, dst, #16 | |
104 | 1: | |
105 | ldp1 A_l, A_h, src, #16 | |
106 | stp1 A_l, A_h, dst, #16 | |
107 | 2: | |
108 | ldp1 A_l, A_h, src, #16 | |
109 | stp1 A_l, A_h, dst, #16 | |
110 | .Ltiny15: | |
111 | /* | |
112 | * Prefer to break one ldp/stp into several load/store to access | |
113 | * memory in an increasing address order,rather than to load/store 16 | |
114 | * bytes from (src-16) to (dst-16) and to backward the src to aligned | |
115 | * address,which way is used in original cortex memcpy. If keeping | |
116 | * the original memcpy process here, memmove need to satisfy the | |
117 | * precondition that src address is at least 16 bytes bigger than dst | |
118 | * address,otherwise some source data will be overwritten when memove | |
119 | * call memcpy directly. To make memmove simpler and decouple the | |
120 | * memcpy's dependency on memmove, withdrew the original process. | |
121 | */ | |
122 | tbz count, #3, 1f | |
123 | ldr1 tmp1, src, #8 | |
124 | str1 tmp1, dst, #8 | |
125 | 1: | |
126 | tbz count, #2, 2f | |
127 | ldr1 tmp1w, src, #4 | |
128 | str1 tmp1w, dst, #4 | |
129 | 2: | |
130 | tbz count, #1, 3f | |
131 | ldrh1 tmp1w, src, #2 | |
132 | strh1 tmp1w, dst, #2 | |
133 | 3: | |
134 | tbz count, #0, .Lexitfunc | |
135 | ldrb1 tmp1w, src, #1 | |
136 | strb1 tmp1w, dst, #1 | |
137 | ||
138 | b .Lexitfunc | |
139 | ||
140 | .Lcpy_over64: | |
141 | subs count, count, #128 | |
142 | b.ge .Lcpy_body_large | |
143 | /* | |
144 | * Less than 128 bytes to copy, so handle 64 here and then jump | |
145 | * to the tail. | |
146 | */ | |
147 | ldp1 A_l, A_h, src, #16 | |
148 | stp1 A_l, A_h, dst, #16 | |
149 | ldp1 B_l, B_h, src, #16 | |
150 | ldp1 C_l, C_h, src, #16 | |
151 | stp1 B_l, B_h, dst, #16 | |
152 | stp1 C_l, C_h, dst, #16 | |
153 | ldp1 D_l, D_h, src, #16 | |
154 | stp1 D_l, D_h, dst, #16 | |
155 | ||
156 | tst count, #0x3f | |
157 | b.ne .Ltail63 | |
158 | b .Lexitfunc | |
159 | ||
160 | /* | |
161 | * Critical loop. Start at a new cache line boundary. Assuming | |
162 | * 64 bytes per line this ensures the entire loop is in one line. | |
163 | */ | |
164 | .p2align L1_CACHE_SHIFT | |
165 | .Lcpy_body_large: | |
166 | /* pre-get 64 bytes data. */ | |
167 | ldp1 A_l, A_h, src, #16 | |
168 | ldp1 B_l, B_h, src, #16 | |
169 | ldp1 C_l, C_h, src, #16 | |
170 | ldp1 D_l, D_h, src, #16 | |
171 | 1: | |
172 | /* | |
173 | * interlace the load of next 64 bytes data block with store of the last | |
174 | * loaded 64 bytes data. | |
175 | */ | |
176 | stp1 A_l, A_h, dst, #16 | |
177 | ldp1 A_l, A_h, src, #16 | |
178 | stp1 B_l, B_h, dst, #16 | |
179 | ldp1 B_l, B_h, src, #16 | |
180 | stp1 C_l, C_h, dst, #16 | |
181 | ldp1 C_l, C_h, src, #16 | |
182 | stp1 D_l, D_h, dst, #16 | |
183 | ldp1 D_l, D_h, src, #16 | |
184 | subs count, count, #64 | |
185 | b.ge 1b | |
186 | stp1 A_l, A_h, dst, #16 | |
187 | stp1 B_l, B_h, dst, #16 | |
188 | stp1 C_l, C_h, dst, #16 | |
189 | stp1 D_l, D_h, dst, #16 | |
190 | ||
191 | tst count, #0x3f | |
192 | b.ne .Ltail63 | |
193 | .Lexitfunc: |