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Diffstat (limited to '')
-rw-r--r-- | src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-SwitchHlpConvFlatRetToRetfProtMode.asm | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-SwitchHlpConvFlatRetToRetfProtMode.asm b/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-SwitchHlpConvFlatRetToRetfProtMode.asm new file mode 100644 index 00000000..e3b40821 --- /dev/null +++ b/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-SwitchHlpConvFlatRetToRetfProtMode.asm @@ -0,0 +1,78 @@ +; $Id: bs3-cmn-SwitchHlpConvFlatRetToRetfProtMode.asm $ +;; @file +; BS3Kit - SwitchHlpConvFlatRetToRetfProtMode +; + +; +; Copyright (C) 2007-2023 Oracle and/or its affiliates. +; +; This file is part of VirtualBox base platform packages, as +; available from https://www.virtualbox.org. +; +; This program is free software; you can redistribute it and/or +; modify it under the terms of the GNU General Public License +; as published by the Free Software Foundation, in version 3 of the +; License. +; +; This program is distributed in the hope that it will be useful, but +; WITHOUT ANY WARRANTY; without even the implied warranty of +; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU +; General Public License for more details. +; +; You should have received a copy of the GNU General Public License +; along with this program; if not, see <https://www.gnu.org/licenses>. +; +; The contents of this file may alternatively be used under the terms +; of the Common Development and Distribution License Version 1.0 +; (CDDL), a copy of it is provided in the "COPYING.CDDL" file included +; in the VirtualBox 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. +; +; SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0 +; + +%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 + |