MdePkg/Library/BaseLib/AArch64/SwitchStack.S

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   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 .text
  17 .align 5
  18
  19 GCC_ASM_EXPORT(InternalSwitchStackAsm)
  20 GCC_ASM_EXPORT(CpuPause)
  21
  22 #/**
  23 #
  24 #  This allows the caller to switch the stack and goes to the new entry point
  25 #
  26 # @param      EntryPoint   The pointer to the location to enter
  27 # @param      Context      Parameter to pass in
  28 # @param      Context2     Parameter2 to pass in
  29 # @param      NewStack     New Location of the stack
  30 #
  31 # @return     Nothing. Goes to the Entry Point passing in the new parameters
  32 #
  33 #**/
  34 #VOID
  35 #EFIAPI
  36 #InternalSwitchStackAsm (
  37 #  SWITCH_STACK_ENTRY_POINT EntryPoint,
  38 #  VOID  *Context,
  39 #  VOID  *Context2,
  40 #  VOID  *NewStack
  41 #  );
  42 #
  43 ASM_PFX(InternalSwitchStackAsm):
  44     mov   x29, #0
  45     mov   x30, x0
  46     mov   sp, x3
  47     mov   x0, x1
  48     mov   x1, x2
  49     ret
  50
  51 #/**
  52 #
  53 #  Requests CPU to pause for a short period of time.
  54 #
  55 #  Requests CPU to pause for a short period of time. Typically used in MP
  56 #  systems to prevent memory starvation while waiting for a spin lock.
  57 #
  58 #**/
  59 #VOID
  60 #EFIAPI
  61 #CpuPause (
  62 #  VOID
  63 #  )
  64 #
  65 ASM_PFX(CpuPause):
  66     nop
  67     nop
  68     nop
  69     nop
  70     nop
  71     ret