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1 | /** @file\r |
2 | Implementation of the EfiCopyMem routine. This function is broken\r |
3 | out into its own source file so that it can be excluded from a\r |
4 | build for a particular platform easily if an optimized version\r |
5 | is desired.\r |
6 | \r |
7 | Copyright (c) 2006, Intel Corporation<BR>\r |
8 | All rights reserved. This program and the accompanying materials\r |
9 | are licensed and made available under the terms and conditions of the BSD License\r |
10 | which accompanies this distribution. The full text of the license may be found at\r |
11 | http://opensource.org/licenses/bsd-license.php\r |
12 | \r |
13 | THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r |
14 | WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r |
15 | \r |
16 | Module Name: EfiCopyMem.c\r |
17 | \r |
18 | **/\r |
19 | \r |
20 | //\r |
21 | // Include common header file for this module.\r |
22 | //\r |
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23 | \r |
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24 | \r |
25 | #include "MemLibInternals.h"\r |
26 | \r |
27 | /**\r |
28 | Copy Length bytes from Source to Destination.\r |
29 | \r |
30 | @param Destination Target of copy\r |
31 | @param Source Place to copy from\r |
32 | @param Length Number of bytes to copy\r |
33 | \r |
34 | @return Destination\r |
35 | \r |
36 | **/\r |
37 | VOID *\r |
38 | EFIAPI\r |
39 | InternalMemCopyMem (\r |
40 | OUT VOID *Destination,\r |
41 | IN CONST VOID *Source,\r |
42 | IN UINTN Length\r |
43 | )\r |
44 | {\r |
45 | //\r |
46 | // Declare the local variables that actually move the data elements as\r |
47 | // volatile to prevent the optimizer from replacing this function with\r |
48 | // the intrinsic memcpy()\r |
49 | //\r |
50 | volatile UINT8 *Destination8;\r |
51 | CONST UINT8 *Source8;\r |
52 | \r |
53 | if (Source > Destination) {\r |
54 | Destination8 = (UINT8*)Destination;\r |
55 | Source8 = (CONST UINT8*)Source;\r |
56 | while (Length-- != 0) {\r |
57 | *(Destination8++) = *(Source8++);\r |
58 | }\r |
59 | } else if (Source < Destination) {\r |
60 | Destination8 = (UINT8*)Destination + Length;\r |
61 | Source8 = (CONST UINT8*)Source + Length;\r |
62 | while (Length-- != 0) {\r |
63 | *(--Destination8) = *(--Source8);\r |
64 | }\r |
65 | }\r |
66 | return Destination;\r |
67 | }\r |