diff options
Diffstat (limited to 'src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-SwitchHlpConvRealModeRetfPopBpDecBpAndReturn.asm')
| -rw-r--r-- | src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-SwitchHlpConvRealModeRetfPopBpDecBpAndReturn.asm | 109 |
1 files changed, 109 insertions, 0 deletions
diff --git a/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-SwitchHlpConvRealModeRetfPopBpDecBpAndReturn.asm b/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-SwitchHlpConvRealModeRetfPopBpDecBpAndReturn.asm new file mode 100644 index 00000000..04b9c912 --- /dev/null +++ b/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-SwitchHlpConvRealModeRetfPopBpDecBpAndReturn.asm @@ -0,0 +1,109 @@ +; $Id: bs3-cmn-SwitchHlpConvRealModeRetfPopBpDecBpAndReturn.asm $ +;; @file +; BS3Kit - SwitchHlpConvRealModeRetfPopBpDecBpAndReturn +; + +; +; 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" + +BS3_EXTERN_CMN Bs3SelFar32ToFlat32 + +;; +; SwitchToXxx helper that converts a 16-bit real mode far return +; into something suitable for the current mode and performs the return. +; +; The caller jmps to this routine. The stack holds an incremented BP (odd is +; far indicator) and a 16-bit far return address. +; +; @uses Nothing. +; @remarks 16-bit ASSUMES we're returning to protected mode!! +; +%if TMPL_BITS == 16 +BS3_BEGIN_TEXT16_FARSTUBS +%endif +BS3_PROC_BEGIN_CMN Bs3SwitchHlpConvRealModeRetfPopBpDecBpAndReturn, BS3_PBC_NEAR +%if TMPL_BITS == 16 + ; Convert the selector of the 16:16 real mode return address to the + ; corresponding 16-bit protected mode selector. + push ax + + mov ax, [bp + 2 + 2] + push ax + BS3_EXTERN_CMN Bs3SelRealModeCodeToProtMode + call Bs3SelRealModeCodeToProtMode ; This doesn't trash any registers (except AX). + add sp, 2 + mov [bp + 2 + 2], ax + + pop ax + + pop bp + dec bp + retf + +%elif TMPL_BITS == 32 + push xAX + push xDX + + movzx eax, word [xSP + xCB*2 + 2 + 2] ; return segment + movzx edx, word [xSP + xCB*2 + 2] ; return offset + shl eax, 4 + add eax, edx + mov [xSP + xCB*2 + 2], eax + + pop xDX + pop xAX + pop bp + dec bp + ret +%else + sub rsp, 2h + + push xAX + push xDX + + movzx eax, word [xSP + xCB*2 + 4 + 2] ; return segment + movzx edx, word [xSP + xCB*2 + 4] ; return offset + shl eax, 4 + add eax, edx + + mov bp, [xSP + xCB*2 + 2] + dec bp + + mov [xSP + xCB*2], rax + + pop xDX + pop xAX + ret +%endif +BS3_PROC_END_CMN Bs3SwitchHlpConvRealModeRetfPopBpDecBpAndReturn + |