MdePkg/Library/BaseLib: Enable VS2017/ARM64 builds

Required GCC assembly files are converted for the MSFT assembler

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Pete Batard <pete@akeo.ie>
Reviewed-by: Liming Gao <liming.gao@intel.com>

MdePkg/Library/BaseLib/AArch64/SwitchStack.asm

@@ -0,0 +1,69 @@
+//------------------------------------------------------------------------------
+//
+// Copyright (c) 2006 - 2009, Intel Corporation. All rights reserved.<BR>
+// Portions copyright (c) 2008 - 2009, Apple Inc. All rights reserved.<BR>
+// Portions copyright (c) 2011 - 2013, ARM Limited. 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.
+//
+//------------------------------------------------------------------------------
+
+  EXPORT InternalSwitchStackAsm
+  EXPORT CpuPause
+  AREA BaseLib_LowLevel, CODE, READONLY
+
+/**
+//
+//  This allows the caller to switch the stack and goes to the new entry point
+//
+// @param      EntryPoint   The pointer to the location to enter
+// @param      Context      Parameter to pass in
+// @param      Context2     Parameter2 to pass in
+// @param      NewStack     New Location of the stack
+//
+// @return     Nothing. Goes to the Entry Point passing in the new parameters
+//
+VOID
+EFIAPI
+InternalSwitchStackAsm (
+  SWITCH_STACK_ENTRY_POINT EntryPoint,
+  VOID  *Context,
+  VOID  *Context2,
+  VOID  *NewStack
+  );
+**/
+InternalSwitchStackAsm
+    mov   x29, #0
+    mov   x30, x0
+    mov   sp, x3
+    mov   x0, x1
+    mov   x1, x2
+    ret
+
+/**
+//
+//  Requests CPU to pause for a short period of time.
+//
+//  Requests CPU to pause for a short period of time. Typically used in MP
+//  systems to prevent memory starvation while waiting for a spin lock.
+//
+VOID
+EFIAPI
+CpuPause (
+  VOID
+  )
+**/
+CpuPause
+    nop
+    nop
+    nop
+    nop
+    nop
+    ret
+
+  END