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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-A20Disable.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-A20Disable.asm')
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diff --git a/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-A20Disable.asm b/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-A20Disable.asm
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+; $Id: bs3-cmn-A20Disable.asm $
+;; @file
+; BS3Kit - Bs3A20Disable.
+;
+
+;
+; 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 Bs3KbdWait
+BS3_EXTERN_CMN Bs3KbdRead
+BS3_EXTERN_CMN Bs3KbdWrite
+
+
+;;
+; Disables the A20 gate.
+;
+; @uses Nothing.
+;
+BS3_PROC_BEGIN_CMN Bs3A20Disable, BS3_PBC_HYBRID_0_ARGS
+ ; Must call both because they may be ORed together on real HW.
+BONLY64 sub rsp, 20h
+ call BS3_CMN_NM(Bs3A20DisableViaKbd)
+ call BS3_CMN_NM(Bs3A20DisableViaPortA)
+BONLY64 add rsp, 20h
+ BS3_HYBRID_RET
+BS3_PROC_END_CMN Bs3A20Disable
+
+
+;;
+; Disables the A20 gate via control port A (PS/2 style).
+;
+; @uses Nothing.
+;
+BS3_PROC_BEGIN_CMN Bs3A20DisableViaPortA, BS3_PBC_HYBRID_0_ARGS
+ push xAX
+
+ ; Use Control port A, assuming a PS/2 style system.
+ in al, 092h
+ test al, 02h
+ jz .done ; avoid trouble writing back the same value.
+ and al, 0fdh ; disable the A20 gate.
+ out 092h, al
+
+.done:
+ pop xAX
+ BS3_HYBRID_RET
+BS3_PROC_END_CMN Bs3A20DisableViaPortA
+
+
+;;
+; Disables the A20 gate via the keyboard controller.
+;
+; @uses Nothing.
+;
+BS3_PROC_BEGIN_CMN Bs3A20DisableViaKbd, BS3_PBC_HYBRID_0_ARGS
+ push xBP
+ mov xBP, xSP
+ push xAX
+ pushf
+ cli
+BONLY64 sub rsp, 20h
+
+ call Bs3KbdWait
+ push 0d0h ; KBD_CCMD_READ_OUTPORT
+ call Bs3KbdRead
+
+ and al, 0fdh ; ~2
+ push xAX
+ push 0d1h ; KBD_CCMD_WRITE_OUTPORT
+ call Bs3KbdWrite
+
+ add xSP, xCB*3 ; Clean up both the above calls.
+
+ mov al, 0ffh ; KBD_CMD_RESET
+ out 64h, al
+ call Bs3KbdWait
+
+BONLY64 add rsp, 20h
+ popf
+ pop xAX
+ pop xBP
+ BS3_HYBRID_RET
+BS3_PROC_END_CMN Bs3A20DisableViaKbd
+