system76-edk2/MdePkg/Library/BaseSynchronizationLib/X64/InterlockedCompareExchange32.c
Michael Kinney 4cee954ea8 MdePkg/BaseSynchronizationLib: Add volatile Interlocked*() APIs
The SpinLock functions in the SynchronicationLib use volatile
parameters to keep compiler from optimizing these functions
too much.  The volatile keyword is missing from the Interlocked*()
functions in this same library instance.  Update the library instance
to consistently use volatile on all functions in the
SynchronizationLib class.

Cc: Liming Gao <liming.gao@intel.com>
Cc: Laszlo Ersek <lersek@redhat.com>
Cc: Andrew Fish <afish@apple.com>
Cc: Jeff Fan <jeff.fan@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Michael Kinney <michael.d.kinney@intel.com>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>
2016-11-17 17:08:19 -08:00

55 lines
1.8 KiB
C

/** @file
InterlockedCompareExchange32 function
Copyright (c) 2006 - 2016, 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.
**/
/**
Microsoft Visual Studio 7.1 Function Prototypes for I/O Intrinsics.
**/
long _InterlockedCompareExchange(
long volatile * Destination,
long Exchange,
long Comperand
);
#pragma intrinsic(_InterlockedCompareExchange)
/**
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
)
{
return _InterlockedCompareExchange (Value, ExchangeValue, CompareValue);
}