1 files changed, 51 insertions, 0 deletions
diff --git a/Core/MdePkg/Library/BaseSynchronizationLib/Ia32/InterlockedCompareExchange16.c b/Core/MdePkg/Library/BaseSynchronizationLib/Ia32/InterlockedCompareExchange16.c
new file mode 100644
index 0000000000..3d5213743e
--- /dev/null
+++ b/Core/MdePkg/Library/BaseSynchronizationLib/Ia32/InterlockedCompareExchange16.c
@@ -0,0 +1,51 @@
+/** @file
+  InterlockedCompareExchange16 function
+
+  Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR>
+  Copyright (c) 2015, Linaro Ltd. 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 16-bit unsigned integer.
+
+  Performs an atomic compare exchange operation on the 16-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 16-bit value for the compare exchange
+                        operation.
+  @param  CompareValue  16-bit value used in compare operation.
+  @param  ExchangeValue 16-bit value used in exchange operation.
+
+  @return The original *Value before exchange.
+
+**/
+UINT16
+EFIAPI
+InternalSyncCompareExchange16 (
+  IN      UINT16                    *Value,
+  IN      UINT16                    CompareValue,
+  IN      UINT16                    ExchangeValue
+  )
+{
+  _asm {
+    mov     ecx, Value
+    mov     ax, CompareValue
+    mov     dx, ExchangeValue
+    lock    cmpxchg [ecx], dx
+  }
+}
+