1 files changed, 50 insertions, 0 deletions
diff --git a/Core/MdePkg/Library/BaseSynchronizationLib/Ia32/InterlockedCompareExchange32.c b/Core/MdePkg/Library/BaseSynchronizationLib/Ia32/InterlockedCompareExchange32.c
new file mode 100644
index 0000000000..a2c6838970
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+++ b/Core/MdePkg/Library/BaseSynchronizationLib/Ia32/InterlockedCompareExchange32.c
@@ -0,0 +1,50 @@
+/** @file
+  InterlockedCompareExchange32 function
+
+  Copyright (c) 2006 - 2010, 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.
+
+**/
+
+
+
+
+/**
+  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      UINT32                    *Value,
+  IN      UINT32                    CompareValue,
+  IN      UINT32                    ExchangeValue
+  )
+{
+  _asm {
+    mov     ecx, Value
+    mov     eax, CompareValue
+    mov     edx, ExchangeValue
+    lock    cmpxchg [ecx], edx
+  }
+}
+