MdePkg/Library/BaseSynchronizationLib/X64/InterlockedCompareExchange64.c

   1 /** @file
   2   InterlockedCompareExchange64 function
   3
   4   Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR>
   5   This program and the accompanying materials
   6   are licensed and made available under the terms and conditions of the BSD License
   7   which accompanies this distribution.  The full text of the license may be found at
   8   http://opensource.org/licenses/bsd-license.php.
   9
  10   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13 **/
  14
  15 /**
  16   Microsoft Visual Studio 7.1 Function Prototypes for I/O Intrinsics.
  17 **/
  18
  19 __int64 _InterlockedCompareExchange64(
  20    __int64 volatile * Destination,
  21    __int64 Exchange,
  22    __int64 Comperand
  23 );
  24
  25 #pragma intrinsic(_InterlockedCompareExchange64)
  26
  27 /**
  28   Performs an atomic compare exchange operation on a 64-bit unsigned integer.
  29
  30   Performs an atomic compare exchange operation on the 64-bit unsigned integer specified
  31   by Value.  If Value is equal to CompareValue, then Value is set to ExchangeValue and
  32   CompareValue is returned.  If Value is not equal to CompareValue, then Value is returned.
  33   The compare exchange operation must be performed using MP safe mechanisms.
  34
  35   @param  Value         A pointer to the 64-bit value for the compare exchange
  36                         operation.
  37   @param  CompareValue  64-bit value used in compare operation.
  38   @param  ExchangeValue 64-bit value used in exchange operation.
  39
  40   @return The original *Value before exchange.
  41
  42 **/
  43 UINT64
  44 EFIAPI
  45 InternalSyncCompareExchange64 (
  46   IN      UINT64                    *Value,
  47   IN      UINT64                    CompareValue,
  48   IN      UINT64                    ExchangeValue
  49   )
  50 {
  51   return _InterlockedCompareExchange64 (Value, ExchangeValue, CompareValue);
  52 }
  53