1 ;------------------------------------------------------------------------------
3 ; CopyMem() worker for ARM
5 ; This file started out as C code that did 64 bit moves if the buffer was
6 ; 32-bit aligned, else it does a byte copy. It also does a byte copy for
7 ; any trailing bytes. It was updated to do 32-byte copies using stm/ldm.
9 ; Copyright (c) 2008 - 2010, Apple Inc. All rights reserved.<BR>
10 ; This program and the accompanying materials
11 ; are licensed and made available under the terms and conditions of the BSD License
12 ; which accompanies this distribution. The full text of the license may be found at
13 ; http://opensource.org/licenses/bsd-license.php
15 ; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
16 ; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
18 ;------------------------------------------------------------------------------
21 Copy Length bytes from Source to Destination. Overlap is OK.
25 @param Destination Target of copy
26 @param Source Place to copy from
27 @param Length Number of bytes to copy
35 OUT VOID *DestinationBuffer,
36 IN CONST VOID *SourceBuffer,
41 INCLUDE AsmMacroExport.inc
43 RVCT_ASM_EXPORT InternalMemCopyMem
44 stmfd sp!, {r4-r11, lr}
45 // Save the input parameters in extra registers (r11 = destination, r14 = source, r12 = length)
51 memcopy_check_overlapped
54 bcc memcopy_check_optim_default
55 // If (dest <= source). But with the previous condition -> If (dest == source)
58 // If (source + length < dest)
61 bcc memcopy_check_optim_default
67 b memcopy_check_optim_overlap
69 memcopy_check_optim_default
70 // Check if we can use an optimized path ((length >= 32) && destination word-aligned && source word-aligned) for the memcopy (optimized path if r0 == 1)
82 memcopy_check_optim_overlap
83 // r10 = dest_end, r14 = source_end
87 // Are we in the optimized case ((length >= 32) && dest_end word-aligned && source_end word-aligned)
97 memcopy_overlapped_non_optim
98 // We read 1 byte from the end of the source buffer
104 // We write 1 byte at the end of the dest buffer
108 bne memcopy_overlapped_non_optim
111 // r10 = dest_end, r14 = source_end
113 // Are we in the optimized case ?
115 beq memcopy_overlapped_non_optim
117 // Optimized Overlapped - Read 32 bytes
123 // If length is less than 32 then disable optim
128 // Optimized Overlapped - Write 32 bytes
132 // while (length != 0)
133 bne memcopy_overlapped
136 memcopy_default_non_optim
146 // r10 = dest, r14 = source
149 beq memcopy_default_non_optim
151 // Optimized memcopy - Read 32 Bytes
156 // If length is less than 32 then disable optim
161 // Optimized memcopy - Write 32 Bytes
164 // while (length != 0)
165 bne memcopy_default_loop
169 ldmfd sp!, {r4-r11, pc}