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4a899227 CM |
1 | /* |
2 | * Copyright (C) 2013 ARM Ltd. | |
280adc19 | 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/ | |
4a899227 CM |
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 | #include <linux/linkage.h> | |
26 | #include <asm/assembler.h> | |
280adc19 | 27 | #include <asm/cache.h> |
4a899227 CM |
28 | |
29 | /* | |
30 | * Move a buffer from src to test (alignment handled by the hardware). | |
31 | * If dest <= src, call memcpy, otherwise copy in reverse order. | |
32 | * | |
33 | * Parameters: | |
34 | * x0 - dest | |
35 | * x1 - src | |
36 | * x2 - n | |
37 | * Returns: | |
38 | * x0 - dest | |
39 | */ | |
280adc19 | 40 | dstin .req x0 |
41 | src .req x1 | |
42 | count .req x2 | |
43 | tmp1 .req x3 | |
44 | tmp1w .req w3 | |
45 | tmp2 .req x4 | |
46 | tmp2w .req w4 | |
47 | tmp3 .req x5 | |
48 | tmp3w .req w5 | |
49 | dst .req x6 | |
50 | ||
51 | A_l .req x7 | |
52 | A_h .req x8 | |
53 | B_l .req x9 | |
54 | B_h .req x10 | |
55 | C_l .req x11 | |
56 | C_h .req x12 | |
57 | D_l .req x13 | |
58 | D_h .req x14 | |
59 | ||
4a899227 | 60 | ENTRY(memmove) |
280adc19 | 61 | cmp dstin, src |
62 | b.lo memcpy | |
63 | add tmp1, src, count | |
64 | cmp dstin, tmp1 | |
65 | b.hs memcpy /* No overlap. */ | |
66 | ||
67 | add dst, dstin, count | |
68 | add src, src, count | |
69 | cmp count, #16 | |
70 | b.lo .Ltail15 /*probably non-alignment accesses.*/ | |
71 | ||
72 | ands tmp2, src, #15 /* Bytes to reach alignment. */ | |
73 | b.eq .LSrcAligned | |
74 | sub count, count, tmp2 | |
75 | /* | |
76 | * process the aligned offset length to make the src aligned firstly. | |
77 | * those extra instructions' cost is acceptable. It also make the | |
78 | * coming accesses are based on aligned address. | |
79 | */ | |
80 | tbz tmp2, #0, 1f | |
81 | ldrb tmp1w, [src, #-1]! | |
82 | strb tmp1w, [dst, #-1]! | |
83 | 1: | |
84 | tbz tmp2, #1, 2f | |
85 | ldrh tmp1w, [src, #-2]! | |
86 | strh tmp1w, [dst, #-2]! | |
87 | 2: | |
88 | tbz tmp2, #2, 3f | |
89 | ldr tmp1w, [src, #-4]! | |
90 | str tmp1w, [dst, #-4]! | |
91 | 3: | |
92 | tbz tmp2, #3, .LSrcAligned | |
93 | ldr tmp1, [src, #-8]! | |
94 | str tmp1, [dst, #-8]! | |
95 | ||
96 | .LSrcAligned: | |
97 | cmp count, #64 | |
98 | b.ge .Lcpy_over64 | |
99 | ||
100 | /* | |
101 | * Deal with small copies quickly by dropping straight into the | |
102 | * exit block. | |
103 | */ | |
104 | .Ltail63: | |
105 | /* | |
106 | * Copy up to 48 bytes of data. At this point we only need the | |
107 | * bottom 6 bits of count to be accurate. | |
108 | */ | |
109 | ands tmp1, count, #0x30 | |
110 | b.eq .Ltail15 | |
111 | cmp tmp1w, #0x20 | |
112 | b.eq 1f | |
113 | b.lt 2f | |
114 | ldp A_l, A_h, [src, #-16]! | |
115 | stp A_l, A_h, [dst, #-16]! | |
116 | 1: | |
117 | ldp A_l, A_h, [src, #-16]! | |
118 | stp A_l, A_h, [dst, #-16]! | |
119 | 2: | |
120 | ldp A_l, A_h, [src, #-16]! | |
121 | stp A_l, A_h, [dst, #-16]! | |
122 | ||
123 | .Ltail15: | |
124 | tbz count, #3, 1f | |
125 | ldr tmp1, [src, #-8]! | |
126 | str tmp1, [dst, #-8]! | |
127 | 1: | |
128 | tbz count, #2, 2f | |
129 | ldr tmp1w, [src, #-4]! | |
130 | str tmp1w, [dst, #-4]! | |
131 | 2: | |
132 | tbz count, #1, 3f | |
133 | ldrh tmp1w, [src, #-2]! | |
134 | strh tmp1w, [dst, #-2]! | |
135 | 3: | |
136 | tbz count, #0, .Lexitfunc | |
137 | ldrb tmp1w, [src, #-1] | |
138 | strb tmp1w, [dst, #-1] | |
139 | ||
140 | .Lexitfunc: | |
141 | ret | |
142 | ||
143 | .Lcpy_over64: | |
144 | subs count, count, #128 | |
145 | b.ge .Lcpy_body_large | |
146 | /* | |
147 | * Less than 128 bytes to copy, so handle 64 bytes here and then jump | |
148 | * to the tail. | |
149 | */ | |
150 | ldp A_l, A_h, [src, #-16] | |
151 | stp A_l, A_h, [dst, #-16] | |
152 | ldp B_l, B_h, [src, #-32] | |
153 | ldp C_l, C_h, [src, #-48] | |
154 | stp B_l, B_h, [dst, #-32] | |
155 | stp C_l, C_h, [dst, #-48] | |
156 | ldp D_l, D_h, [src, #-64]! | |
157 | stp D_l, D_h, [dst, #-64]! | |
158 | ||
159 | tst count, #0x3f | |
160 | b.ne .Ltail63 | |
161 | ret | |
162 | ||
163 | /* | |
164 | * Critical loop. Start at a new cache line boundary. Assuming | |
165 | * 64 bytes per line this ensures the entire loop is in one line. | |
166 | */ | |
167 | .p2align L1_CACHE_SHIFT | |
168 | .Lcpy_body_large: | |
169 | /* pre-load 64 bytes data. */ | |
170 | ldp A_l, A_h, [src, #-16] | |
171 | ldp B_l, B_h, [src, #-32] | |
172 | ldp C_l, C_h, [src, #-48] | |
173 | ldp D_l, D_h, [src, #-64]! | |
174 | 1: | |
175 | /* | |
176 | * interlace the load of next 64 bytes data block with store of the last | |
177 | * loaded 64 bytes data. | |
178 | */ | |
179 | stp A_l, A_h, [dst, #-16] | |
180 | ldp A_l, A_h, [src, #-16] | |
181 | stp B_l, B_h, [dst, #-32] | |
182 | ldp B_l, B_h, [src, #-32] | |
183 | stp C_l, C_h, [dst, #-48] | |
184 | ldp C_l, C_h, [src, #-48] | |
185 | stp D_l, D_h, [dst, #-64]! | |
186 | ldp D_l, D_h, [src, #-64]! | |
187 | subs count, count, #64 | |
188 | b.ge 1b | |
189 | stp A_l, A_h, [dst, #-16] | |
190 | stp B_l, B_h, [dst, #-32] | |
191 | stp C_l, C_h, [dst, #-48] | |
192 | stp D_l, D_h, [dst, #-64]! | |
193 | ||
194 | tst count, #0x3f | |
195 | b.ne .Ltail63 | |
196 | ret | |
4a899227 | 197 | ENDPROC(memmove) |