/** @file | |
InterlockedCompareExchange16 function | |
Copyright (c) 2006 - 2016, Intel Corporation. All rights reserved.<BR> | |
Copyright (c) 2015, Linaro Ltd. All rights reserved.<BR> | |
SPDX-License-Identifier: BSD-2-Clause-Patent | |
**/ | |
/** | |
Performs an atomic compare exchange operation on a 16-bit unsigned integer. | |
Performs an atomic compare exchange operation on the 16-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 16-bit value for the compare exchange | |
operation. | |
@param CompareValue 16-bit value used in compare operation. | |
@param ExchangeValue 16-bit value used in exchange operation. | |
@return The original *Value before exchange. | |
**/ | |
UINT16 | |
EFIAPI | |
InternalSyncCompareExchange16 ( | |
IN volatile UINT16 *Value, | |
IN UINT16 CompareValue, | |
IN UINT16 ExchangeValue | |
) | |
{ | |
_asm { | |
mov ecx, Value | |
mov ax, CompareValue | |
mov dx, ExchangeValue | |
lock cmpxchg [ecx], dx | |
} | |
} |