1 files changed, 42 insertions, 0 deletions
diff --git a/OvmfPkg/XenBusDxe/Ia32/InterlockedCompareExchange16.nasm b/OvmfPkg/XenBusDxe/Ia32/InterlockedCompareExchange16.nasm
new file mode 100644
index 0000000000..d45582dd81
--- /dev/null
+++ b/OvmfPkg/XenBusDxe/Ia32/InterlockedCompareExchange16.nasm
@@ -0,0 +1,42 @@
+;------------------------------------------------------------------------------
+;
+; Copyright (c) 2006, 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:
+;
+;   InterlockedCompareExchange16.Asm
+;
+; Abstract:
+;
+;   InterlockedCompareExchange16 function
+;
+; Notes:
+;
+;------------------------------------------------------------------------------
+
+    SECTION .text
+
+;------------------------------------------------------------------------------
+; UINT32
+; EFIAPI
+; InternalSyncCompareExchange16 (
+;   IN      UINT16                    *Value,
+;   IN      UINT16                    CompareValue,
+;   IN      UINT16                    ExchangeValue
+;   );
+;------------------------------------------------------------------------------
+global ASM_PFX(InternalSyncCompareExchange16)
+ASM_PFX(InternalSyncCompareExchange16):
+    mov     ecx, [esp + 4]
+    mov     eax, [esp + 8]
+    mov     edx, [esp + 12]
+    lock    cmpxchg [ecx], dx
+    ret
+