1 files changed, 39 insertions, 0 deletions
diff --git a/MdePkg/Library/BaseSynchronizationLib/X64/InterlockedDecrement.nasm b/MdePkg/Library/BaseSynchronizationLib/X64/InterlockedDecrement.nasm
new file mode 100644
index 000000000000..0325fdf93e90
--- /dev/null
+++ b/MdePkg/Library/BaseSynchronizationLib/X64/InterlockedDecrement.nasm
@@ -0,0 +1,39 @@
+;------------------------------------------------------------------------------
+;
+; Copyright (c) 2006 - 2016, 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.
+;
+; Module Name:
+;
+;   InterlockedDecrement.Asm
+;
+; Abstract:
+;
+;   InterlockedDecrement function
+;
+; Notes:
+;
+;------------------------------------------------------------------------------
+
+    DEFAULT REL
+    SECTION .text
+
+;------------------------------------------------------------------------------
+; UINT32
+; EFIAPI
+; InternalSyncDecrement (
+;   IN      volatile UINT32           *Value
+;   );
+;------------------------------------------------------------------------------
+global ASM_PFX(InternalSyncDecrement)
+ASM_PFX(InternalSyncDecrement):
+    lock    dec     dword [rcx]
+    mov     eax, [rcx]
+    ret
+