IntelFspPkg/Library/BaseFspSwitchStackLib/Ia32/Stack.asm

   1 ;------------------------------------------------------------------------------
   2 ;
   3 ; Copyright (c) 2014 - 2015, Intel Corporation. All rights reserved.<BR>
   4 ; SPDX-License-Identifier: BSD-2-Clause-Patent
   5 ;
   6 ; Abstract:
   7 ;
   8 ;   Switch the stack from temporary memory to permenent memory.
   9 ;
  10 ;------------------------------------------------------------------------------
  11
  12     .586p
  13     .model  flat,C
  14     .code
  15
  16 ;------------------------------------------------------------------------------
  17 ; UINT32
  18 ; EFIAPI
  19 ; Pei2LoaderSwitchStack (
  20 ;   VOID
  21 ;   )
  22 ;------------------------------------------------------------------------------
  23 EXTERNDEF  C   MeasurePoint:PROC
  24 Pei2LoaderSwitchStack   PROC C PUBLIC
  25     xor     eax, eax
  26     jmp     FspSwitchStack
  27 Pei2LoaderSwitchStack   ENDP
  28
  29 ;------------------------------------------------------------------------------
  30 ; UINT32
  31 ; EFIAPI
  32 ; Loader2PeiSwitchStack (
  33 ;   VOID
  34 ;   )
  35 ;------------------------------------------------------------------------------
  36 Loader2PeiSwitchStack   PROC C PUBLIC
  37     jmp     FspSwitchStack
  38 Loader2PeiSwitchStack   ENDP
  39
  40 ;------------------------------------------------------------------------------
  41 ; UINT32
  42 ; EFIAPI
  43 ; FspSwitchStack (
  44 ;   VOID
  45 ;   )
  46 ;------------------------------------------------------------------------------
  47 EXTERNDEF  C   SwapStack:PROC
  48 FspSwitchStack   PROC C PUBLIC
  49     ; Save current contexts
  50     push    eax
  51     pushfd
  52     cli
  53     pushad
  54     sub     esp, 8
  55     sidt    fword ptr [esp]
  56
  57     ; Load new stack
  58     push    esp
  59     call    SwapStack
  60     mov     esp, eax
  61
  62     ; Restore previous contexts
  63     lidt    fword ptr [esp]
  64     add     esp, 8
  65     popad
  66     popfd
  67     add     esp, 4
  68     ret
  69 FspSwitchStack   ENDP
  70
  71     END