MdePkg/Library/BaseLib/AArch64/SwitchStack.asm

   1 ;------------------------------------------------------------------------------
   2 ;
   3 ; Copyright (c) 2006 - 2009, Intel Corporation. All rights reserved.<BR>
   4 ; Portions copyright (c) 2008 - 2009, Apple Inc. All rights reserved.<BR>
   5 ; Portions copyright (c) 2011 - 2013, ARM Limited. All rights reserved.<BR>
   6 ; SPDX-License-Identifier: BSD-2-Clause-Patent
   7 ;
   8 ;------------------------------------------------------------------------------
   9
  10   EXPORT InternalSwitchStackAsm
  11   EXPORT CpuPause
  12   AREA BaseLib_LowLevel, CODE, READONLY
  13
  14 ;/**
  15 ;
  16 ;  This allows the caller to switch the stack and goes to the new entry point
  17 ;
  18 ; @param      EntryPoint   The pointer to the location to enter
  19 ; @param      Context      Parameter to pass in
  20 ; @param      Context2     Parameter2 to pass in
  21 ; @param      NewStack     New Location of the stack
  22 ;
  23 ; @return     Nothing. Goes to the Entry Point passing in the new parameters
  24 ;
  25 ;**/
  26 ;VOID
  27 ;EFIAPI
  28 ;InternalSwitchStackAsm (
  29 ;  SWITCH_STACK_ENTRY_POINT EntryPoint,
  30 ;  VOID  *Context,
  31 ;  VOID  *Context2,
  32 ;  VOID  *NewStack
  33 ;  );
  34 ;
  35 InternalSwitchStackAsm
  36     mov   x29, #0
  37     mov   x30, x0
  38     mov   sp, x3
  39     mov   x0, x1
  40     mov   x1, x2
  41     ret
  42
  43 ;/**
  44 ;
  45 ;  Requests CPU to pause for a short period of time.
  46 ;
  47 ;  Requests CPU to pause for a short period of time. Typically used in MP
  48 ;  systems to prevent memory starvation while waiting for a spin lock.
  49 ;
  50 ;**/
  51 ;VOID
  52 ;EFIAPI
  53 ;CpuPause (
  54 ;  VOID
  55 ;  )
  56 ;
  57 CpuPause
  58     nop
  59     nop
  60     nop
  61     nop
  62     nop
  63     ret
  64
  65   END