1 files changed, 68 insertions, 0 deletions
diff --git a/MdePkg/Library/BaseLib/Arm/SwitchStack.S b/MdePkg/Library/BaseLib/Arm/SwitchStack.S
new file mode 100644
index 000000000000..e7433d43ea62
--- /dev/null
+++ b/MdePkg/Library/BaseLib/Arm/SwitchStack.S
@@ -0,0 +1,68 @@
+//------------------------------------------------------------------------------ 
+//
+// 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, 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.
+//
+//------------------------------------------------------------------------------
+  
+.text
+.align 5
+
+GCC_ASM_EXPORT(InternalSwitchStackAsm)
+GCC_ASM_EXPORT(CpuPause)            
+  
+/**
+//
+//  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
+  );
+**/
+ASM_PFX(InternalSwitchStackAsm):
+    MOV   LR, R0
+    MOV   SP, R3
+    MOV   R0, R1
+    MOV   R1, R2
+    BX    LR
+
+/**
+//
+//  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
+  )
+**/
+ASM_PFX(CpuPause):
+    nop
+    nop
+    nop
+    nop
+    nop
+    BX    LR