idt.c

一个微型操作系统源码

/*
 * OSV
 * Copyright (C) 2002 Ciprian DOSOFTEI <[e-mail]>
 * All rights reserved.
 * 
 * http://backster.free.fr/osv
 *
 * This file is part of the OSV project. OSV is free software, also known as
 * "open source"; you can redistribute it and/or modify it under the terms 
 * of the GNU General Public License (GPL), version 2, as published by the Free
 * Software Foundation (FSF). To explore alternate licensing terms, contact 
 * the author at [e-mail] or [phone].
 * 
 * OSV 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 GPL for more details.  You should have
 * received a copy of the GPL along with OSV; see the file COPYING.  If
 * not, write to the FSF, 59 Temple Place #330, Boston, MA 02111-1307, USA.
 */

#include <idt.h>
#include <gdt.h>

gate *IDT = (gate *)(GDT_SIZE * sizeof(descriptor));

void setupIDT(void) {
    dword IDTR[2];

    memset(IDT, 0, IDT_SIZE * sizeof(gate));
    IDTR[0] = ((IDT_SIZE * sizeof(gate)) - 1) << 16;
    IDTR[1] = (dword)IDT;

    __asm__ __volatile__("lidt (%0)" : : "r" (((byte *)IDTR) + 2));
}

void interruptIDT(gate *g, word selector, dword offset, byte dpl) {
    g->offset0_15 = offset;
    g->offset16_31 = offset >> 16;
    g->selector = selector;
    g->zero = 0;
    g->p = 1;
    g->dpl = dpl;
    g->type = 0xE;
}

void trapIDT(gate *g, word selector, dword offset, byte dpl) {
    g->offset0_15 = offset;
    g->offset16_31 = offset >> 16;
    g->selector = selector;
    g->zero = 0;
    g->p = 1;
    g->dpl = dpl;
    g->type = 0xF;
}

void taskIDT(gate *g, word selector, byte dpl)
{
    g->offset0_15 = 0;
    g->offset16_31 = 0;
    g->selector = selector;
    g->zero = 0;
    g->p = 1;
    g->dpl = dpl;
    g->type = 5;
}