--- /dev/null
+#------------------------------------------------------------------------------
+#
+# 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:
+#
+# ReadMsr64.S
+#
+# Abstract:
+#
+# AsmReadMsr64 function
+#
+# Notes:
+#
+#------------------------------------------------------------------------------
+
+
+#------------------------------------------------------------------------------
+# UINT64
+# EFIAPI
+# AsmReadMsr64 (
+# IN UINT32 Index
+# );
+#------------------------------------------------------------------------------
+.global _AsmReadMsr64;
+.align 16;
+_AsmReadMsr64:
+ rdmsr # edx & eax are zero extended
+ shl $0x20, %rdx
+ or %rdx, %rax
+ ret