source: vbox/trunk/src/VBox/Devices/PC/BIOS/pmsetup.inc

; $Id: pmsetup.inc 98103 2023-01-17 14:15:46Z vboxsync $
;; @file
; Initial system setup which needs to run in protected mode.
;

;
; Copyright (C) 2004-2023 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>.
;
; SPDX-License-Identifier: GPL-3.0-only
;

SVR             equ     0FEE000F0h
LVT_LINT0       equ     0FEE00350h
LVT_LINT1       equ     0FEE00360h

public          pmode_setup

;; Enable the local APIC and program LINT0/LINT1 entries. Without that,
;; virtual wire interrupts could not be delivered. Note that the APIC must
;; be enabled first because when disabled, all LVTs are forced masked.

pmode_setup     proc    near

                .386
                push    eax
                push    esi
                pushf
                cli                     ; Interrupts would kill us!
                call    pmode_enter

                mov     eax, cr0        ; Clear CR0.CD and CR0.NW
                and     eax, 09FFFFFFFh
                mov     cr0, eax

                mov     esi, SVR        ; Program the SVR -- enable the APIC,
                mov     eax, 010Fh      ; set spurious interrupt vector to 15
                mov     [esi], eax

                mov     esi, LVT_LINT0  ; Program LINT0 to ExtINT and unmask
                mov     eax, [esi]
                and     eax, 0FFFE00FFh
                or      ah,  7
                mov     [esi], eax

                mov     esi, LVT_LINT1  ; Program LINT1 to NMI and unmask
                mov     eax, [esi]
                and     eax, 0FFFE00FFh
                or      ah,  4
                mov     [esi], eax

                call    pmode_exit
                popf
                pop     esi
                pop     eax
                SET_DEFAULT_CPU_286
                ret

pmode_setup     endp