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path: root/IntelFspPkg/Library/BaseFspSwitchStackLib/Ia32/Stack.asm
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;------------------------------------------------------------------------------
;
; Copyright (c) 2014, Intel Corporation. All rights reserved.<BR>
; This program and the accompanying materials
; are licensed and made available under the terms and conditions of the BSD License
; which accompanies this distribution.  The full text of the license may be found at
; http://opensource.org/licenses/bsd-license.php.
;
; THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
; WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
;
; Abstract:
;
;   Switch the stack from temporary memory to permenent memory.
;
;------------------------------------------------------------------------------

    .586p
    .model  flat,C
    .code

;------------------------------------------------------------------------------
; UINT32
; EFIAPI
; Pei2LoaderSwitchStack (
;   VOID
;   )
;------------------------------------------------------------------------------
EXTERNDEF  C   MeasurePoint:PROC
Pei2LoaderSwitchStack   PROC C PUBLIC
    jmp     Loader2PeiSwitchStack
Pei2LoaderSwitchStack   ENDP

;------------------------------------------------------------------------------
; UINT32
; EFIAPI
; Loader2PeiSwitchStack (
;   VOID
;   )
;------------------------------------------------------------------------------
EXTERNDEF  C   SwapStack:PROC
Loader2PeiSwitchStack   PROC C PUBLIC
    ; Save current contexts
    push    offset exit
    pushfd
    cli
    pushad
    sub     esp, 8
    sidt    fword ptr [esp]

    ; Load new stack
    push    esp
    call    SwapStack
    mov     esp, eax

    ; Restore previous contexts
    lidt    fword ptr [esp]
    add     esp, 8
    popad
    popfd
exit:
    ret
Loader2PeiSwitchStack   ENDP

    END