Split out Synchronization Library from Base Library

[mirror_edk2.git] / MdePkg / Library / BaseSynchronizationLib / Ia32 / InterlockedCompareExchange64.c

/** @file\r
  InterlockedCompareExchange64 function\r
\r
  Copyright (c) 2006 - 2008, Intel Corporation<BR>\r
  All rights reserved. This program and the accompanying materials\r
  are licensed and made available under the terms and conditions of the BSD License\r
  which accompanies this distribution.  The full text of the license may be found at\r
  http://opensource.org/licenses/bsd-license.php\r
\r
  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
\r
**/\r
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/**\r
  Performs an atomic compare exchange operation on a 64-bit unsigned integer.\r
\r
  Performs an atomic compare exchange operation on the 64-bit unsigned integer specified\r
  by Value.  If Value is equal to CompareValue, then Value is set to ExchangeValue and\r
  CompareValue is returned.  If Value is not equal to CompareValue, then Value is returned.\r
  The compare exchange operation must be performed using MP safe mechanisms.\r
\r
  @param  Value         A pointer to the 64-bit value for the compare exchange\r
                        operation.\r
  @param  CompareValue  64-bit value used in compare operation.\r
  @param  ExchangeValue 64-bit value used in exchange operation.\r
\r
  @return The original *Value before exchange.\r
\r
**/\r
UINT64\r
EFIAPI\r
InternalSyncCompareExchange64 (\r
  IN      UINT64                    *Value,\r
  IN      UINT64                    CompareValue,\r
  IN      UINT64                    ExchangeValue\r
  )\r
{\r
  _asm {\r
    mov     esi, Value\r
    mov     eax, dword ptr [CompareValue + 0]\r
    mov     edx, dword ptr [CompareValue + 4]\r
    mov     ebx, dword ptr [ExchangeValue + 0]\r
    mov     ecx, dword ptr [ExchangeValue + 4]\r
    lock    cmpxchg8b   qword ptr [esi]\r
  }\r
}\r