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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:17:27 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-11 08:17:27 +0000
commitf215e02bf85f68d3a6106c2a1f4f7f063f819064 (patch)
tree6bb5b92c046312c4e95ac2620b10ddf482d3fa8b /src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-SwitchTo32Bit.asm
parentInitial commit. (diff)
downloadvirtualbox-f215e02bf85f68d3a6106c2a1f4f7f063f819064.tar.xz
virtualbox-f215e02bf85f68d3a6106c2a1f4f7f063f819064.zip
Adding upstream version 7.0.14-dfsg.upstream/7.0.14-dfsg
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-SwitchTo32Bit.asm')
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diff --git a/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-SwitchTo32Bit.asm b/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-SwitchTo32Bit.asm
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+++ b/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-SwitchTo32Bit.asm
@@ -0,0 +1,162 @@
+; $Id: bs3-cmn-SwitchTo32Bit.asm $
+;; @file
+; BS3Kit - Bs3SwitchTo32Bit
+;
+
+;
+; 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 Bs3SelProtFar32ToFlat32
+BS3_EXTERN_CMN Bs3Syscall
+%endif
+%if TMPL_BITS != 32
+BS3_EXTERN_DATA16 g_bBs3CurrentMode
+TMPL_BEGIN_TEXT
+%endif
+
+
+;;
+; @cproto BS3_DECL(void) Bs3SwitchTo32Bit(void);
+;
+; @remarks Does not require 20h of parameter scratch space in 64-bit mode.
+;
+BS3_PROC_BEGIN_CMN Bs3SwitchTo32Bit, BS3_PBC_NEAR
+%if TMPL_BITS == 32
+ ret
+%else
+ %if TMPL_BITS == 16
+ push ax ; Reserve space for larger return value (adjusted in 32-bit code).
+ push eax
+ pushfd
+ push edx
+ %else
+ pushfq
+ mov [rsp + 4], eax
+ %endif
+ cli
+
+ %if TMPL_BITS == 16
+ ; Check for v8086 mode, we need to exit it to enter 32-bit mode.
+ mov ax, seg g_bBs3CurrentMode
+ mov ds, ax
+ mov al, [BS3_DATA16_WRT(g_bBs3CurrentMode)]
+ test al, BS3_MODE_CODE_V86
+ jz .not_v8086
+
+ ; Calc flat stack into edx.
+ mov dx, ss
+ movzx edx, dx
+ shl edx, 4
+ add dx, sp
+ adc edx, 0 ; edx = flat stack address corresponding to ss:sp
+
+ ; Switch to 16-bit ring0 and go on to do the far jump to 32-bit code.
+ mov ax, BS3_SYSCALL_TO_RING0
+ call Bs3Syscall
+
+ mov xAX, BS3_SEL_R0_CS32
+ jmp .do_far_jump
+ %endif
+
+.not_v8086:
+ %if TMPL_BITS == 16
+ ; Calc flat stack into edx.
+ movzx eax, sp
+ push ecx
+ push ebx
+ push ss
+ push eax
+ call Bs3SelProtFar32ToFlat32
+ add sp, 6
+ shl edx, 16
+ mov dx, ax ; edx = flat stack address corresponding to ss:sp
+ pop ebx
+ pop ecx
+ %endif
+
+ ; Calc ring addend.
+ mov ax, cs
+ and xAX, 3
+ shl xAX, BS3_SEL_RING_SHIFT
+ add xAX, BS3_SEL_R0_CS32
+
+ ; Create far return for switching to 32-bit mode.
+.do_far_jump:
+ push sAX
+ %if TMPL_BITS == 16
+ push dword .thirty_two_bit wrt FLAT
+ o32 retf
+ %else
+ push .thirty_two_bit
+ o64 retf
+ %endif
+
+BS3_SET_BITS 32
+.thirty_two_bit:
+ ; Load 32-bit segment registers.
+ add eax, BS3_SEL_R0_SS32 - BS3_SEL_R0_CS32
+ mov ss, ax
+ %if TMPL_BITS == 16
+ mov esp, edx ; Load flat stack address.
+ %endif
+
+ add eax, BS3_SEL_R0_DS32 - BS3_SEL_R0_SS32
+ mov ds, ax
+ mov es, ax
+
+ ; Update globals.
+ and byte [BS3_DATA16_WRT(g_bBs3CurrentMode)], ~BS3_MODE_CODE_MASK
+ or byte [BS3_DATA16_WRT(g_bBs3CurrentMode)], BS3_MODE_CODE_32
+
+ %if TMPL_BITS == 16
+ ; Adjust the return address.
+ movzx eax, word [esp + 4*3 + 2]
+ add eax, BS3_ADDR_BS3TEXT16
+ mov [esp + 4*3], eax
+ %endif
+
+ ; Restore and return.
+ %if TMPL_BITS == 16
+ pop edx
+ %endif
+ popfd
+ pop eax
+TONLY64 ret 4
+TNOT64 ret
+%endif
+BS3_PROC_END_CMN Bs3SwitchTo32Bit
+
+;; @todo far 16-bit variant.
+