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 VOID
  32 EFIAPI
  33 InternalSwitchStackAsm (
  34   SWITCH_STACK_ENTRY_POINT EntryPoint,
  35   VOID  *Context,
  36   VOID  *Context2,
  37   VOID  *NewStack
  38   );
  39 **/
  40 InternalSwitchStackAsm
  41     mov   x29, #0
  42     mov   x30, x0
  43     mov   sp, x3
  44     mov   x0, x1
  45     mov   x1, x2
  46     ret
  47
  48 /**
  49 //
  50 //  Requests CPU to pause for a short period of time.
  51 //
  52 //  Requests CPU to pause for a short period of time. Typically used in MP
  53 //  systems to prevent memory starvation while waiting for a spin lock.
  54 //
  55 VOID
  56 EFIAPI
  57 CpuPause (
  58   VOID
  59   )
  60 **/
  61 CpuPause
  62     nop
  63     nop
  64     nop
  65     nop
  66     nop
  67     ret
  68
  69   END