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720d3c5f 1/** @file\r
2 InterlockedCompareExchange64 function\r
3\r
2fc59a00 4 Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR>\r
e2d9bfb2 5 This program and the accompanying materials\r
720d3c5f 6 are licensed and made available under the terms and conditions of the BSD License\r
7 which accompanies this distribution. The full text of the license may be found at\r
2fc59a00 8 http://opensource.org/licenses/bsd-license.php.\r
720d3c5f 9\r
10 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
11 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
12\r
13**/\r
14\r
15\r
16\r
17\r
18/**\r
19 Performs an atomic compare exchange operation on a 64-bit unsigned integer.\r
20\r
21 Performs an atomic compare exchange operation on the 64-bit unsigned integer specified\r
22 by Value. If Value is equal to CompareValue, then Value is set to ExchangeValue and\r
23 CompareValue is returned. If Value is not equal to CompareValue, then Value is returned.\r
24 The compare exchange operation must be performed using MP safe mechanisms.\r
25\r
26 @param Value A pointer to the 64-bit value for the compare exchange\r
27 operation.\r
2fc59a00 28 @param CompareValue A 64-bit value used in a compare operation.\r
29 @param ExchangeValue A 64-bit value used in an exchange operation.\r
720d3c5f 30\r
31 @return The original *Value before exchange.\r
32\r
33**/\r
34UINT64\r
35EFIAPI\r
36InternalSyncCompareExchange64 (\r
37 IN UINT64 *Value,\r
38 IN UINT64 CompareValue,\r
39 IN UINT64 ExchangeValue\r
40 )\r
41{\r
42 _asm {\r
43 mov esi, Value\r
44 mov eax, dword ptr [CompareValue + 0]\r
45 mov edx, dword ptr [CompareValue + 4]\r
46 mov ebx, dword ptr [ExchangeValue + 0]\r
47 mov ecx, dword ptr [ExchangeValue + 4]\r
48 lock cmpxchg8b qword ptr [esi]\r
49 }\r
50}\r