MdePkg/Library/BaseSynchronizationLib/X64/InterlockedCompareExchange32.c

   1 /** @file
   2   InterlockedCompareExchange32 function
   3
   4   Copyright (c) 2006 - 2016, Intel Corporation. All rights reserved.<BR>
   5   SPDX-License-Identifier: BSD-2-Clause-Patent
   6
   7 **/
   8
   9 /**
  10   Microsoft Visual Studio 7.1 Function Prototypes for I/O Intrinsics.
  11 **/
  12
  13 long
  14 _InterlockedCompareExchange (
  15   long volatile  *Destination,
  16   long           Exchange,
  17   long           Comperand
  18   );
  19
  20 #pragma intrinsic(_InterlockedCompareExchange)
  21
  22 /**
  23   Performs an atomic compare exchange operation on a 32-bit unsigned integer.
  24
  25   Performs an atomic compare exchange operation on the 32-bit unsigned integer
  26   specified by Value.  If Value is equal to CompareValue, then Value is set to
  27   ExchangeValue and CompareValue is returned.  If Value is not equal to CompareValue,
  28   then Value is returned.  The compare exchange operation must be performed using
  29   MP safe mechanisms.
  30
  31   @param  Value         A pointer to the 32-bit value for the compare exchange
  32                         operation.
  33   @param  CompareValue  32-bit value used in compare operation.
  34   @param  ExchangeValue 32-bit value used in exchange operation.
  35
  36   @return The original *Value before exchange.
  37
  38 **/
  39 UINT32
  40 EFIAPI
  41 InternalSyncCompareExchange32 (
  42   IN      volatile UINT32  *Value,
  43   IN      UINT32           CompareValue,
  44   IN      UINT32           ExchangeValue
  45   )
  46 {
  47   return _InterlockedCompareExchange (Value, ExchangeValue, CompareValue);
  48 }