Add IntelFspPkg to support create FSP bin based on EDKII.

Contributed-under: TianoCore Contribution Agreement 1.0

Signed off by: Ravi Rangarajan <ravi.p.rangarajan@intel.com>
Reviewed by: Maurice Ma <maurice.ma@intel.com>
Reviewed by: Jiewen Yao <jiewen.yao@intel.com>
Reviewed by: Giri Mudusuru <giri.p.mudusuru@intel.com>
Reviewed by: Liming Gao <liming.gao@intel.com>


git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@15705 6f19259b-4bc3-4df7-8a09-765794883524

IntelFspPkg/Library/BaseFspSwitchStackLib/FspSwitchStackLib.c

@@ -0,0 +1,42 @@
+/** @file
+
+  Copyright (c) 2014, 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.
+
+**/
+
+#include <Base.h>
+#include <Library/BaseLib.h>
+#include <Library/FspCommonLib.h>
+
+/**
+
+  Switch the current stack to the previous saved stack.
+
+  @param[in]  NewStack         The new stack to be switched.
+
+  @return OldStack         After switching to the saved stack,
+                           this value will be saved in eax before returning.
+
+
+**/
+UINT32
+SwapStack (
+  IN  UINT32 NewStack
+  )
+{
+  FSP_GLOBAL_DATA  *FspData;
+  UINT32         OldStack;
+
+  FspData  = GetFspGlobalDataPointer ();
+  OldStack = FspData->CoreStack;
+  FspData->CoreStack = NewStack;
+  return OldStack;
+}
+