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; $Id: bs3-cmn-SwitchHlpConvFlatRetToRetfProtMode.asm $
;; @file
; BS3Kit - SwitchHlpConvFlatRetToRetfProtMode
;
;
; Copyright (C) 2007-2019 Oracle Corporation
;
; This file is part of VirtualBox Open Source Edition (OSE), as
; available from http://www.virtualbox.org. This file is free software;
; you can redistribute it and/or modify it under the terms of the GNU
; General Public License (GPL) as published by the Free Software
; Foundation, in version 2 as it comes in the "COPYING" file of the
; VirtualBox OSE distribution. VirtualBox OSE is distributed in the
; hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
;
; The contents of this file may alternatively be used under the terms
; of the Common Development and Distribution License Version 1.0
; (CDDL) only, as it comes in the "COPYING.CDDL" file of the
; VirtualBox OSE distribution, in which case the provisions of the
; CDDL are applicable instead of those of the GPL.
;
; You may elect to license modified versions of this file under the
; terms and conditions of either the GPL or the CDDL or both.
;
%include "bs3kit-template-header.mac"
%if TMPL_BITS != 16
BS3_EXTERN_CMN Bs3SelFlatCodeToProtFar16
;;
; SwitchToXxx helper that converts a 32-bit or 64-bit flat return address
; into a 16-bit protected mode far return.
;
;
; The caller calls this routine before switching modes. The flat return
; to be converted is immediately after our own return address on the stack.
;
; @uses Nothing.
; @remarks No 16-bit version.
;
BS3_PROC_BEGIN_CMN Bs3SwitchHlpConvFlatRetToRetfProtMode, BS3_PBC_NEAR
%if TMPL_BITS == 64
push xAX
push xCX
sub xSP, 20h
mov xCX, [xSP + xCB*3 + 20h]
call Bs3SelFlatCodeToProtFar16 ; well behaved assembly function, only clobbers ecx
mov [xSP + xCB*3 + 20h + 4], eax
add xSP, 20h
pop xCX
pop xAX
ret 4
%else
xchg eax, [xSP + xCB]
push xAX
call Bs3SelFlatCodeToProtFar16 ; well behaved assembly function, only clobbers eax
add xSP, 4
xchg [xSP + xCB], eax
ret
%endif
BS3_PROC_END_CMN Bs3SwitchHlpConvFlatRetToRetfProtMode
%endif ; 32 || 64
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