IntelFspPkg/Library/BaseFspSwitchStackLib/Ia32/Stack.s

   1 #------------------------------------------------------------------------------
   2 #
   3 # Copyright (c) 2014, 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 ASM_GLOBAL ASM_PFX(Pei2LoaderSwitchStack)
  19 ASM_GLOBAL ASM_PFX(Loader2PeiSwitchStack)
  20
  21 #------------------------------------------------------------------------------
  22 # UINT32
  23 # EFIAPI
  24 # Pei2LoaderSwitchStack (
  25 #   VOID
  26 #   )
  27 #------------------------------------------------------------------------------
  28 ASM_GLOBAL ASM_PFX(Pei2LoaderSwitchStack)
  29 ASM_PFX(Pei2LoaderSwitchStack):
  30     jmp     ASM_PFX(Loader2PeiSwitchStack)
  31
  32 #------------------------------------------------------------------------------
  33 # UINT32
  34 # EFIAPI
  35 # Loader2PeiSwitchStack (
  36 #   )
  37 #------------------------------------------------------------------------------
  38 ASM_GLOBAL ASM_PFX(Loader2PeiSwitchStack)
  39 ASM_PFX(Loader2PeiSwitchStack):
  40 #Save current contexts
  41     push    $exit
  42     pushf
  43     pushf
  44     cli
  45     pusha
  46     push    $0x0
  47     push    $0x0
  48     sidt    (%esp)
  49
  50     # Load new stack
  51     push   %esp
  52     call   ASM_PFX(SwapStack)
  53     mov    %eax,%esp
  54
  55     # Restore previous contexts
  56     lidt    (%esp)
  57     add     $8,%esp
  58     popa
  59     popf
  60     popf
  61 exit:
  62     ret
  63
  64