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3402aac7 | 1 | #------------------------------------------------------------------------------\r |
d39eb83c | 2 | #\r |
3 | # CopyMem() worker for ARM\r | |
4 | #\r | |
5 | # This file started out as C code that did 64 bit moves if the buffer was\r | |
6 | # 32-bit aligned, else it does a byte copy. It also does a byte copy for\r | |
3402aac7 | 7 | # any trailing bytes. It was updated to do 32-byte copies using stm/ldm.\r |
d39eb83c | 8 | #\r |
d6ebcab7 HT |
9 | # Copyright (c) 2008 - 2010, Apple Inc. All rights reserved.<BR>\r |
10 | # This program and the accompanying materials\r | |
d39eb83c | 11 | # are licensed and made available under the terms and conditions of the BSD License\r |
12 | # which accompanies this distribution. The full text of the license may be found at\r | |
13 | # http://opensource.org/licenses/bsd-license.php\r | |
14 | #\r | |
15 | # THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r | |
16 | # WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r | |
17 | #\r | |
18 | #------------------------------------------------------------------------------\r | |
19 | \r | |
8ca934aa AB |
20 | #include <AsmMacroIoLib.h>\r |
21 | \r | |
d39eb83c | 22 | /**\r |
23 | Copy Length bytes from Source to Destination. Overlap is OK.\r | |
24 | \r | |
3402aac7 | 25 | This implementation\r |
d39eb83c | 26 | \r |
27 | @param Destination Target of copy\r | |
28 | @param Source Place to copy from\r | |
29 | @param Length Number of bytes to copy\r | |
30 | \r | |
31 | @return Destination\r | |
32 | \r | |
33 | \r | |
34 | VOID *\r | |
35 | EFIAPI\r | |
36 | InternalMemCopyMem (\r | |
37 | OUT VOID *DestinationBuffer,\r | |
38 | IN CONST VOID *SourceBuffer,\r | |
39 | IN UINTN Length\r | |
40 | )\r | |
41 | **/\r | |
8ca934aa | 42 | ASM_FUNC(InternalMemCopyMem)\r |
2ac288f9 | 43 | stmfd sp!, {r4-r11, lr}\r |
643ec0e7 | 44 | // Save the input parameters in extra registers (r11 = destination, r14 = source, r12 = length)\r |
2ac288f9 | 45 | mov r11, r0\r |
46 | mov r10, r0\r | |
643ec0e7 | 47 | mov r12, r2\r |
48 | mov r14, r1\r | |
3402aac7 | 49 | \r |
643ec0e7 | 50 | memcopy_check_overlapped:\r |
51 | cmp r11, r1\r | |
52 | // If (dest < source)\r | |
53 | bcc memcopy_check_optim_default\r | |
54 | // If (dest <= source). But with the previous condition -> If (dest == source)\r | |
55 | bls memcopy_end\r | |
56 | \r | |
57 | // If (source + length < dest)\r | |
58 | rsb r3, r1, r11\r | |
59 | cmp r12, r3\r | |
60 | bcc memcopy_check_optim_default\r | |
61 | \r | |
3402aac7 | 62 | // If (length == 0)\r |
643ec0e7 | 63 | cmp r12, #0\r |
64 | beq memcopy_end\r | |
3402aac7 | 65 | \r |
643ec0e7 | 66 | b memcopy_check_optim_overlap\r |
67 | \r | |
68 | memcopy_check_optim_default:\r | |
69 | // Check if we can use an optimized path ((length >= 32) && destination word-aligned && source word-aligned) for the memcopy (optimized path if r0 == 1)\r | |
70 | tst r0, #0xF\r | |
2ac288f9 | 71 | movne r0, #0\r |
643ec0e7 | 72 | bne memcopy_default\r |
73 | tst r1, #0xF\r | |
2ac288f9 | 74 | movne r3, #0\r |
75 | moveq r3, #1\r | |
76 | cmp r2, #31\r | |
77 | movls r0, #0\r | |
78 | andhi r0, r3, #1\r | |
643ec0e7 | 79 | b memcopy_default\r |
3402aac7 | 80 | \r |
643ec0e7 | 81 | memcopy_check_optim_overlap:\r |
82 | // r10 = dest_end, r14 = source_end\r | |
83 | add r10, r11, r12\r | |
84 | add r14, r12, r1\r | |
85 | \r | |
86 | // Are we in the optimized case ((length >= 32) && dest_end word-aligned && source_end word-aligned)\r | |
87 | cmp r2, #31\r | |
2ac288f9 | 88 | movls r0, #0\r |
643ec0e7 | 89 | movhi r0, #1\r |
90 | tst r10, #0xF\r | |
91 | movne r0, #0\r | |
92 | tst r14, #0xF\r | |
93 | movne r0, #0\r | |
94 | b memcopy_overlapped\r | |
3402aac7 | 95 | \r |
643ec0e7 | 96 | memcopy_overlapped_non_optim:\r |
97 | // We read 1 byte from the end of the source buffer\r | |
98 | sub r3, r14, #1\r | |
99 | sub r12, r12, #1\r | |
3402aac7 | 100 | ldrb r3, [r3, #0]\r |
2ac288f9 | 101 | sub r2, r10, #1\r |
643ec0e7 | 102 | cmp r12, #0\r |
103 | // We write 1 byte at the end of the dest buffer\r | |
2ac288f9 | 104 | sub r10, r10, #1\r |
643ec0e7 | 105 | sub r14, r14, #1\r |
2ac288f9 | 106 | strb r3, [r2, #0]\r |
643ec0e7 | 107 | bne memcopy_overlapped_non_optim\r |
108 | b memcopy_end\r | |
109 | \r | |
110 | // r10 = dest_end, r14 = source_end\r | |
111 | memcopy_overlapped:\r | |
112 | // Are we in the optimized case ?\r | |
113 | cmp r0, #0\r | |
114 | beq memcopy_overlapped_non_optim\r | |
3402aac7 | 115 | \r |
643ec0e7 | 116 | // Optimized Overlapped - Read 32 bytes\r |
117 | sub r14, r14, #32\r | |
118 | sub r12, r12, #32\r | |
119 | cmp r12, #31\r | |
120 | ldmia r14, {r2-r9}\r | |
3402aac7 | 121 | \r |
643ec0e7 | 122 | // If length is less than 32 then disable optim\r |
123 | movls r0, #0\r | |
3402aac7 | 124 | \r |
643ec0e7 | 125 | cmp r12, #0\r |
3402aac7 RC |
126 | \r |
127 | // Optimized Overlapped - Write 32 bytes\r | |
643ec0e7 | 128 | sub r10, r10, #32\r |
129 | stmia r10, {r2-r9}\r | |
3402aac7 | 130 | \r |
643ec0e7 | 131 | // while (length != 0)\r |
132 | bne memcopy_overlapped\r | |
133 | b memcopy_end\r | |
3402aac7 | 134 | \r |
643ec0e7 | 135 | memcopy_default_non_optim:\r |
136 | // Byte copy\r | |
3402aac7 | 137 | ldrb r3, [r14], #1\r |
643ec0e7 | 138 | sub r12, r12, #1\r |
2ac288f9 | 139 | strb r3, [r10], #1\r |
3402aac7 | 140 | \r |
643ec0e7 | 141 | memcopy_default:\r |
142 | cmp r12, #0\r | |
143 | beq memcopy_end\r | |
3402aac7 | 144 | \r |
643ec0e7 | 145 | // r10 = dest, r14 = source\r |
146 | memcopy_default_loop:\r | |
2ac288f9 | 147 | cmp r0, #0\r |
643ec0e7 | 148 | beq memcopy_default_non_optim\r |
3402aac7 | 149 | \r |
643ec0e7 | 150 | // Optimized memcopy - Read 32 Bytes\r |
151 | sub r12, r12, #32\r | |
152 | cmp r12, #31\r | |
153 | ldmia r14!, {r2-r9}\r | |
3402aac7 | 154 | \r |
643ec0e7 | 155 | // If length is less than 32 then disable optim\r |
2ac288f9 | 156 | movls r0, #0\r |
3402aac7 | 157 | \r |
643ec0e7 | 158 | cmp r12, #0\r |
3402aac7 | 159 | \r |
643ec0e7 | 160 | // Optimized memcopy - Write 32 Bytes\r |
2ac288f9 | 161 | stmia r10!, {r2-r9}\r |
643ec0e7 | 162 | \r |
163 | // while (length != 0)\r | |
164 | bne memcopy_default_loop\r | |
3402aac7 | 165 | \r |
643ec0e7 | 166 | memcopy_end:\r |
2ac288f9 | 167 | mov r0, r11\r |
168 | ldmfd sp!, {r4-r11, pc}\r | |
3402aac7 | 169 | \r |