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Diffstat (limited to '')
-rw-r--r-- | src/VBox/ValidationKit/bootsectors/bs3kit/bs3-mode-SwitchToPE16_32.asm | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-mode-SwitchToPE16_32.asm b/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-mode-SwitchToPE16_32.asm new file mode 100644 index 00000000..587e6446 --- /dev/null +++ b/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-mode-SwitchToPE16_32.asm @@ -0,0 +1,114 @@ +; $Id: bs3-mode-SwitchToPE16_32.asm $ +;; @file +; BS3Kit - Bs3SwitchToPE16_32 +; + +; +; 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" + + +;; +; Switch to 32-bit code under 16-bit unpaged protected mode sys/tss from any other mode. +; +; @cproto BS3_DECL(void) Bs3SwitchToPE16_32(void); +; +; @uses Nothing (except high 32-bit register parts). +; +; @remarks Obviously returns to 32-bit mode, even if the caller was +; in 16-bit or 64-bit mode. +; +; @remarks Does not require 20h of parameter scratch space in 64-bit mode. +; +BS3_GLOBAL_NAME_EX TMPL_NM(Bs3SwitchToPE16_32_Safe), function, 0 +BS3_PROC_BEGIN_MODE Bs3SwitchToPE16_32, BS3_PBC_NEAR +%ifdef TMPL_PE16_32 + ret + +%else + ; + ; Make sure we're in the 16-bit segment and then call Bs3SwitchToPE16. + ; + %if TMPL_BITS != 16 + jmp .sixteen_bit_segment +BS3_BEGIN_TEXT16 + BS3_SET_BITS TMPL_BITS +BS3_GLOBAL_LOCAL_LABEL .sixteen_bit_segment + %endif + extern TMPL_NM(Bs3SwitchToPE16) + call TMPL_NM(Bs3SwitchToPE16) + BS3_SET_BITS 16 + + ; + ; Switch to 32-bit mode. + ; + extern _Bs3SwitchTo32Bit_c16 + %if TMPL_BITS == 16 + jmp _Bs3SwitchTo32Bit_c16 + %else + call _Bs3SwitchTo32Bit_c16 + BS3_SET_BITS 32 + %if TMPL_BITS == 32 + ret + %else + ret 4 ; Return and pop 4 bytes of "parameters" (unused return address). + %endif + %endif +%endif +BS3_PROC_END_MODE Bs3SwitchToPE16_32 + + +%if TMPL_BITS == 16 +;; +; Custom far stub. +BS3_BEGIN_TEXT16_FARSTUBS +BS3_PROC_BEGIN_MODE Bs3SwitchToPE16_32, BS3_PBC_FAR + inc bp + push bp + mov bp, sp + + ; Call the real thing. + call TMPL_NM(Bs3SwitchToPE16_32) + BS3_SET_BITS 32 + + ; Jmp to common code for the tedious conversion. + %if BS3_MODE_IS_RM_OR_V86(TMPL_MODE) + extern _Bs3SwitchHlpConvRealModeRetfPopBpDecBpAndReturn_c32 + jmp _Bs3SwitchHlpConvRealModeRetfPopBpDecBpAndReturn_c32 + %else + extern _Bs3SwitchHlpConvProtModeRetfPopBpDecBpAndReturn_c32 + jmp _Bs3SwitchHlpConvProtModeRetfPopBpDecBpAndReturn_c32 + %endif + BS3_SET_BITS 16 +BS3_PROC_END_MODE Bs3SwitchToPE16_32 +%endif + |