audk/MdePkg/Library/BaseSynchronizationLib/Ia32/InterlockedCompareExchange64.c

51 lines
1.7 KiB
C

/** @file
InterlockedCompareExchange64 function
Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>
This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution. The full text of the license may be found at
http://opensource.org/licenses/bsd-license.php
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/
/**
Performs an atomic compare exchange operation on a 64-bit unsigned integer.
Performs an atomic compare exchange operation on the 64-bit unsigned integer specified
by Value. If Value is equal to CompareValue, then Value is set to ExchangeValue and
CompareValue is returned. If Value is not equal to CompareValue, then Value is returned.
The compare exchange operation must be performed using MP safe mechanisms.
@param Value A pointer to the 64-bit value for the compare exchange
operation.
@param CompareValue 64-bit value used in compare operation.
@param ExchangeValue 64-bit value used in exchange operation.
@return The original *Value before exchange.
**/
UINT64
EFIAPI
InternalSyncCompareExchange64 (
IN UINT64 *Value,
IN UINT64 CompareValue,
IN UINT64 ExchangeValue
)
{
_asm {
mov esi, Value
mov eax, dword ptr [CompareValue + 0]
mov edx, dword ptr [CompareValue + 4]
mov ebx, dword ptr [ExchangeValue + 0]
mov ecx, dword ptr [ExchangeValue + 4]
lock cmpxchg8b qword ptr [esi]
}
}