1 files changed, 42 insertions, 0 deletions
diff --git a/MdePkg/Library/BaseSynchronizationLib/Ia32/InterlockedDecrement.c b/MdePkg/Library/BaseSynchronizationLib/Ia32/InterlockedDecrement.c
new file mode 100644
index 0000000000..d1f0868a83
--- /dev/null
+++ b/MdePkg/Library/BaseSynchronizationLib/Ia32/InterlockedDecrement.c
@@ -0,0 +1,42 @@
+/** @file
+  InterlockedDecrement function
+
+  Copyright (c) 2006 - 2008, Intel Corporation<BR>
+  All rights reserved. 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 decrement of an 32-bit unsigned integer.
+
+  Performs an atomic decrement of the 32-bit unsigned integer specified by
+  Value and returns the decrement value. The decrement operation must be
+  performed using MP safe mechanisms. The state of the return value is not
+  guaranteed to be MP safe.
+
+  @param  Value A pointer to the 32-bit value to decrement.
+
+  @return The decrement value.
+
+**/
+UINT32
+EFIAPI
+InternalSyncDecrement (
+  IN      UINT32                    *Value
+  )
+{
+  _asm {
+    mov     eax, Value
+    lock    dec     dword ptr [eax]
+    mov     eax, [eax]
+  }
+}