1 files changed, 39 insertions, 0 deletions
diff --git a/MdePkg/Library/BaseLib/X64/InterlockedCompareExchange64.S b/MdePkg/Library/BaseLib/X64/InterlockedCompareExchange64.S
new file mode 100644
index 0000000000..ae27964292
--- /dev/null
+++ b/MdePkg/Library/BaseLib/X64/InterlockedCompareExchange64.S
@@ -0,0 +1,39 @@
+#------------------------------------------------------------------------------
+#
+# Copyright (c) 2006, Intel Corporation
+# 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.
+#
+# Module Name:
+#
+#   InterlockedCompareExchange64.S
+#
+# Abstract:
+#
+#   InterlockedCompareExchange64 function
+#
+# Notes:
+#
+#------------------------------------------------------------------------------
+
+
+#------------------------------------------------------------------------------
+# UINT64
+# EFIAPI
+# InterlockedCompareExchange64 (
+#   IN      UINT64                    *Value,
+#   IN      UINT64                    CompareValue,
+#   IN      UINT64                    ExchangeValue
+#   );
+#------------------------------------------------------------------------------
+.global _InternalSyncCompareExchange64;
+.align 16;
+_InternalSyncCompareExchange64:
+    mov     %rsi, %rax
+    lock    cmpxchg %rdx,(%rdi)
+    ret