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 ; Copyright (c) 2016, Linaro Ltd. All rights reserved.<BR>
11 ; This program and the accompanying materials
12 ; are licensed and made available under the terms and conditions of the BSD License
13 ; which accompanies this distribution. The full text of the license may be found at
14 ; http://opensource.org/licenses/bsd-license.php
16 ; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
17 ; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
19 ;------------------------------------------------------------------------------
21 EXPORT InternalMemCopyMem
22 AREA SetMem, CODE, READONLY
26 stmfd sp!, {r4-r11, lr}
27 // Save the input parameters in extra registers (r11 = destination, r14 = source, r12 = length)
33 memcopy_check_overlapped
36 bcc memcopy_check_optim_default
38 // If (source + length < dest)
41 bcc memcopy_check_optim_default
42 b memcopy_check_optim_overlap
44 memcopy_check_optim_default
45 // Check if we can use an optimized path ((length >= 32) && destination word-aligned && source word-aligned) for the memcopy (optimized path if r0 == 1)
57 memcopy_check_optim_overlap
58 // r10 = dest_end, r14 = source_end
62 // Are we in the optimized case ((length >= 32) && dest_end word-aligned && source_end word-aligned)
72 memcopy_overlapped_non_optim
73 // We read 1 byte from the end of the source buffer
79 // We write 1 byte at the end of the dest buffer
83 bne memcopy_overlapped_non_optim
86 // r10 = dest_end, r14 = source_end
88 // Are we in the optimized case ?
90 beq memcopy_overlapped_non_optim
92 // Optimized Overlapped - Read 32 bytes
98 // If length is less than 32 then disable optim
103 // Optimized Overlapped - Write 32 bytes
107 // while (length != 0)
108 bne memcopy_overlapped
111 memcopy_default_non_optim
121 // r10 = dest, r14 = source
124 beq memcopy_default_non_optim
126 // Optimized memcopy - Read 32 Bytes
131 // If length is less than 32 then disable optim
136 // Optimized memcopy - Write 32 Bytes
139 // while (length != 0)
140 bne memcopy_default_loop
144 ldmfd sp!, {r4-r11, pc}