IntelFspPkg/Library/BaseFspSwitchStackLib/Ia32/Stack.s

   1 #------------------------------------------------------------------------------
   2 #
   3 # Copyright (c) 2014 - 2015, Intel Corporation. All rights reserved.<BR>
   4 # This program and the accompanying materials
   5 # are licensed and made available under the terms and conditions of the BSD License
   6 # which accompanies this distribution.  The full text of the license may be found at
   7 # http://opensource.org/licenses/bsd-license.php.
   8 #
   9 # THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  10 # WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  11 #
  12 # Abstract:
  13 #
  14 #   Switch the stack from temporary memory to permenent memory.
  15 #
  16 #------------------------------------------------------------------------------
  17
  18
  19 #------------------------------------------------------------------------------
  20 # UINT32
  21 # EFIAPI
  22 # Pei2LoaderSwitchStack (
  23 #   VOID
  24 #   )
  25 #------------------------------------------------------------------------------
  26 ASM_GLOBAL ASM_PFX(Pei2LoaderSwitchStack)
  27 ASM_PFX(Pei2LoaderSwitchStack):
  28     jmp     ASM_PFX(Loader2PeiSwitchStack)
  29
  30 #------------------------------------------------------------------------------
  31 # UINT32
  32 # EFIAPI
  33 # Loader2PeiSwitchStack (
  34 #   )
  35 #------------------------------------------------------------------------------
  36 ASM_GLOBAL ASM_PFX(Loader2PeiSwitchStack)
  37 ASM_PFX(Loader2PeiSwitchStack):
  38     #
  39     #Save current contexts
  40     #
  41     push    $exit
  42     pushf
  43     cli
  44     pusha
  45     sub     $0x08, %esp
  46     sidt    (%esp)
  47
  48     #
  49     # Load new stack
  50     #
  51     push   %esp
  52     call   ASM_PFX(SwapStack)
  53     movl   %eax, %esp
  54
  55     #
  56     # Restore previous contexts
  57     #
  58     lidt    (%esp)
  59     add     $0x08,%esp
  60     popa
  61     popf
  62 exit:
  63     ret
  64
  65