1 files changed, 65 insertions, 0 deletions
diff --git a/roms/edk2/MdePkg/Library/BaseLib/AArch64/SwitchStack.asm b/roms/edk2/MdePkg/Library/BaseLib/AArch64/SwitchStack.asm
new file mode 100644
index 000000000..56dce5cbe
--- /dev/null
+++ b/roms/edk2/MdePkg/Library/BaseLib/AArch64/SwitchStack.asm
@@ -0,0 +1,65 @@
+;------------------------------------------------------------------------------
+;
+; 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>
+; SPDX-License-Identifier: BSD-2-Clause-Patent
+;
+;------------------------------------------------------------------------------
+
+  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