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 ; This program and the accompanying materials
   7 ; are licensed and made available under the terms and conditions of the BSD License
   8 ; which accompanies this distribution.  The full text of the license may be found at
   9 ; http://opensource.org/licenses/bsd-license.php.
  10 ;
  11 ; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  12 ; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  13 ;
  14 ;------------------------------------------------------------------------------
  15
  16   EXPORT InternalSwitchStackAsm
  17   EXPORT CpuPause
  18   AREA BaseLib_LowLevel, CODE, READONLY
  19
  20 ;/**
  21 ;
  22 ;  This allows the caller to switch the stack and goes to the new entry point
  23 ;
  24 ; @param      EntryPoint   The pointer to the location to enter
  25 ; @param      Context      Parameter to pass in
  26 ; @param      Context2     Parameter2 to pass in
  27 ; @param      NewStack     New Location of the stack
  28 ;
  29 ; @return     Nothing. Goes to the Entry Point passing in the new parameters
  30 ;
  31 ;**/
  32 ;VOID
  33 ;EFIAPI
  34 ;InternalSwitchStackAsm (
  35 ;  SWITCH_STACK_ENTRY_POINT EntryPoint,
  36 ;  VOID  *Context,
  37 ;  VOID  *Context2,
  38 ;  VOID  *NewStack
  39 ;  );
  40 ;
  41 InternalSwitchStackAsm
  42     mov   x29, #0
  43     mov   x30, x0
  44     mov   sp, x3
  45     mov   x0, x1
  46     mov   x1, x2
  47     ret
  48
  49 ;/**
  50 ;
  51 ;  Requests CPU to pause for a short period of time.
  52 ;
  53 ;  Requests CPU to pause for a short period of time. Typically used in MP
  54 ;  systems to prevent memory starvation while waiting for a spin lock.
  55 ;
  56 ;**/
  57 ;VOID
  58 ;EFIAPI
  59 ;CpuPause (
  60 ;  VOID
  61 ;  )
  62 ;
  63 CpuPause
  64     nop
  65     nop
  66     nop
  67     nop
  68     nop
  69     ret
  70
  71   END