Added to support X64 port (with SV5 ABI). May be able to remove after we port everything, but Sec, to EFI X64 ABI.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@10683 6f19259b-4bc3-4df7-8a09-765794883524

UnixPkg/Library/UnixBaseLib/X64/WriteMsr64.c

@@ -0,0 +1,42 @@
+/** @file
+  CpuBreakpoint function.
+
+  Copyright (c) 2006 - 2010, 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.
+
+**/
+
+/**
+  Microsoft Visual Studio 7.1 Function Prototypes for I/O Intrinsics.
+**/
+
+void __writemsr (unsigned long Register, unsigned __int64 Value);
+
+#pragma intrinsic(__writemsr)
+
+/**
+  Write data to MSR.
+
+  @param  Index                The register index of MSR.
+  @param  Value                Data wants to be written.
+
+  @return Value written to MSR.
+
+**/
+UINT64
+EFIAPI
+AsmWriteMsr64 (
+  IN UINT32  Index,
+  IN UINT64  Value
+  )
+{
+  __writemsr (Index, Value);
+  return Value;
+}
+