MdePkg/Library/BaseLib/Arm/SwitchStack.S

//------------------------------------------------------------------------------
//
// Copyright (c) 2006 - 2018, 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