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 _InterlockedCompareExchange(
  14    long volatile * Destination,
  15    long Exchange,
  16    long Comperand
  17 );
  18
  19 #pragma intrinsic(_InterlockedCompareExchange)
  20
  21 /**
  22   Performs an atomic compare exchange operation on a 32-bit unsigned integer.
  23
  24   Performs an atomic compare exchange operation on the 32-bit unsigned integer
  25   specified by Value.  If Value is equal to CompareValue, then Value is set to
  26   ExchangeValue and CompareValue is returned.  If Value is not equal to CompareValue,
  27   then Value is returned.  The compare exchange operation must be performed using
  28   MP safe mechanisms.
  29
  30   @param  Value         A pointer to the 32-bit value for the compare exchange
  31                         operation.
  32   @param  CompareValue  32-bit value used in compare operation.
  33   @param  ExchangeValue 32-bit value used in exchange operation.
  34
  35   @return The original *Value before exchange.
  36
  37 **/
  38 UINT32
  39 EFIAPI
  40 InternalSyncCompareExchange32 (
  41   IN      volatile UINT32           *Value,
  42   IN      UINT32                    CompareValue,
  43   IN      UINT32                    ExchangeValue
  44   )
  45 {
  46   return _InterlockedCompareExchange (Value, ExchangeValue, CompareValue);
  47 }
  48