| 1 | ; $Id: bs3-cmn-SwitchHlpConvFlatRetToRetfProtMode.asm 82968 2020-02-04 10:35:17Z vboxsync $
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| 2 | ;; @file
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| 3 | ; BS3Kit - SwitchHlpConvFlatRetToRetfProtMode
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| 4 | ;
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| 5 |
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| 6 | ;
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| 7 | ; Copyright (C) 2007-2020 Oracle Corporation
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| 8 | ;
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| 9 | ; This file is part of VirtualBox Open Source Edition (OSE), as
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| 10 | ; available from http://www.virtualbox.org. This file is free software;
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| 11 | ; you can redistribute it and/or modify it under the terms of the GNU
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| 12 | ; General Public License (GPL) as published by the Free Software
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| 13 | ; Foundation, in version 2 as it comes in the "COPYING" file of the
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| 14 | ; VirtualBox OSE distribution. VirtualBox OSE is distributed in the
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| 15 | ; hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
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| 16 | ;
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| 17 | ; The contents of this file may alternatively be used under the terms
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| 18 | ; of the Common Development and Distribution License Version 1.0
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| 19 | ; (CDDL) only, as it comes in the "COPYING.CDDL" file of the
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| 20 | ; VirtualBox OSE distribution, in which case the provisions of the
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| 21 | ; CDDL are applicable instead of those of the GPL.
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| 22 | ;
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| 23 | ; You may elect to license modified versions of this file under the
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| 24 | ; terms and conditions of either the GPL or the CDDL or both.
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| 25 | ;
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| 26 |
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| 27 | %include "bs3kit-template-header.mac"
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| 28 |
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| 29 | %if TMPL_BITS != 16
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| 30 | BS3_EXTERN_CMN Bs3SelFlatCodeToProtFar16
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| 31 |
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| 32 | ;;
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| 33 | ; SwitchToXxx helper that converts a 32-bit or 64-bit flat return address
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| 34 | ; into a 16-bit protected mode far return.
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| 35 | ;
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| 36 | ;
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| 37 | ; The caller calls this routine before switching modes. The flat return
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| 38 | ; to be converted is immediately after our own return address on the stack.
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| 39 | ;
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| 40 | ; @uses Nothing.
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| 41 | ; @remarks No 16-bit version.
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| 42 | ;
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| 43 | BS3_PROC_BEGIN_CMN Bs3SwitchHlpConvFlatRetToRetfProtMode, BS3_PBC_NEAR
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| 44 | %if TMPL_BITS == 64
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| 45 | push xAX
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| 46 | push xCX
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| 47 | sub xSP, 20h
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| 48 |
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| 49 | mov xCX, [xSP + xCB*3 + 20h]
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| 50 | call Bs3SelFlatCodeToProtFar16 ; well behaved assembly function, only clobbers ecx
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| 51 | mov [xSP + xCB*3 + 20h + 4], eax
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| 52 |
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| 53 | add xSP, 20h
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| 54 | pop xCX
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| 55 | pop xAX
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| 56 | ret 4
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| 57 | %else
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| 58 | xchg eax, [xSP + xCB]
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| 59 | push xAX
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| 60 | call Bs3SelFlatCodeToProtFar16 ; well behaved assembly function, only clobbers eax
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| 61 | add xSP, 4
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| 62 | xchg [xSP + xCB], eax
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| 63 | ret
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| 64 | %endif
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| 65 | BS3_PROC_END_CMN Bs3SwitchHlpConvFlatRetToRetfProtMode
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| 66 |
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| 67 | %endif ; 32 || 64
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| 68 |
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