IntelFspPkg/Library/BaseFspSwitchStackLib/Ia32/Stack.asm

   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     .586p
  19     .model  flat,C
  20     .code
  21
  22 ;------------------------------------------------------------------------------
  23 ; UINT32
  24 ; EFIAPI
  25 ; Pei2LoaderSwitchStack (
  26 ;   VOID
  27 ;   )
  28 ;------------------------------------------------------------------------------
  29 EXTERNDEF  C   MeasurePoint:PROC
  30 Pei2LoaderSwitchStack   PROC C PUBLIC
  31     jmp     Loader2PeiSwitchStack
  32 Pei2LoaderSwitchStack   ENDP
  33
  34 ;------------------------------------------------------------------------------
  35 ; UINT32
  36 ; EFIAPI
  37 ; Loader2PeiSwitchStack (
  38 ;   VOID
  39 ;   )
  40 ;------------------------------------------------------------------------------
  41 EXTERNDEF  C   SwapStack:PROC
  42 Loader2PeiSwitchStack   PROC C PUBLIC
  43     ; Save current contexts
  44     push    offset exit
  45     pushfd
  46     cli
  47     pushad
  48     sub     esp, 8
  49     sidt    fword ptr [esp]
  50
  51     ; Load new stack
  52     push    esp
  53     call    SwapStack
  54     mov     esp, eax
  55
  56     ; Restore previous contexts
  57     lidt    fword ptr [esp]
  58     add     esp, 8
  59     popad
  60     popfd
  61 exit:
  62     ret
  63 Loader2PeiSwitchStack   ENDP
  64
  65     END