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/** @file
InterlockedCompareExchange32 function
Copyright (c) 2006 - 2016, Intel Corporation. All rights reserved.<BR>
SPDX-License-Identifier: BSD-2-Clause-Patent
**/
/**
Performs an atomic compare exchange operation on a 32-bit unsigned integer.
Performs an atomic compare exchange operation on the 32-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 32-bit value for the compare exchange
operation.
@param CompareValue 32-bit value used in compare operation.
@param ExchangeValue 32-bit value used in exchange operation.
@return The original *Value before exchange.
**/
UINT32
EFIAPI
InternalSyncCompareExchange32 (
IN volatile UINT32 *Value,
IN UINT32 CompareValue,
IN UINT32 ExchangeValue
)
{
_asm {
mov ecx, Value
mov eax, CompareValue
mov edx, ExchangeValue
lock cmpxchg [ecx], edx
}
}
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