1 /** @file
2 InterlockedCompareExchange64 function
3
4 Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR>
5 This program and the accompanying materials
6 are licensed and made available under the terms and conditions of the BSD License
7 which accompanies this distribution. The full text of the license may be found at
8 http://opensource.org/licenses/bsd-license.php.
9
10 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
11 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
12
13 **/
14
15
16
17
18 /**
19 Performs an atomic compare exchange operation on a 64-bit unsigned integer.
20
21 Performs an atomic compare exchange operation on the 64-bit unsigned integer specified
22 by Value. If Value is equal to CompareValue, then Value is set to ExchangeValue and
23 CompareValue is returned. If Value is not equal to CompareValue, then Value is returned.
24 The compare exchange operation must be performed using MP safe mechanisms.
25
26 @param Value A pointer to the 64-bit value for the compare exchange
27 operation.
28 @param CompareValue A 64-bit value used in a compare operation.
29 @param ExchangeValue A 64-bit value used in an exchange operation.
30
31 @return The original *Value before exchange.
32
33 **/
34 UINT64
35 EFIAPI
InternalSyncCompareExchange64(IN UINT64 * Value,IN UINT64 CompareValue,IN UINT64 ExchangeValue)36 InternalSyncCompareExchange64 (
37 IN UINT64 *Value,
38 IN UINT64 CompareValue,
39 IN UINT64 ExchangeValue
40 )
41 {
42 _asm {
43 mov esi, Value
44 mov eax, dword ptr [CompareValue + 0]
45 mov edx, dword ptr [CompareValue + 4]
46 mov ebx, dword ptr [ExchangeValue + 0]
47 mov ecx, dword ptr [ExchangeValue + 4]
48 lock cmpxchg8b qword ptr [esi]
49 }
50 }
51