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/** @file
Implementation of synchronization functions on Itanium.
Copyright (c) 2006, Intel Corporation<BR>
All rights reserved. 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.
Module Name: Synchronization.c
**/
/**
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
);
/**
Performs an atomic increment of an 32-bit unsigned integer.
Performs an atomic increment of the 32-bit unsigned integer specified by
Value and returns the incremented value. The increment operation must be
performed using MP safe mechanisms. The state of the return value is not
guaranteed to be MP safe.
@param Value A pointer to the 32-bit value to increment.
@return The incremented value.
**/
UINT32
EFIAPI
InternalSyncIncrement (
IN volatile UINT32 *Value
)
{
UINT32 OriginalValue;
do {
OriginalValue = *Value;
} while (OriginalValue != InternalSyncCompareExchange32 (
Value,
OriginalValue,
OriginalValue + 1
));
return OriginalValue + 1;
}
/**
Performs an atomic decrement of an 32-bit unsigned integer.
Performs an atomic decrement of the 32-bit unsigned integer specified by
Value and returns the decrement value. The decrement operation must be
performed using MP safe mechanisms. The state of the return value is not
guaranteed to be MP safe.
@param Value A pointer to the 32-bit value to decrement.
@return The decrement value.
**/
UINT32
EFIAPI
InternalSyncDecrement (
IN volatile UINT32 *Value
)
{
UINT32 OriginalValue;
do {
OriginalValue = *Value;
} while (OriginalValue != InternalSyncCompareExchange32 (
Value,
OriginalValue,
OriginalValue - 1
));
return OriginalValue - 1;
}
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