pic.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 <pic.h>

static word IRQmask;

#define SLAVE_IRQ 8
#define MASTER_SLAVE 2

#define	ICU0 0x20
#define	ICU1 0xA0

#define	ICU_RESET 0x11

void reprogramPIC(ushort master, ushort slave) {
    outb(ICU0, ICU_RESET); io_wait();
    outb(ICU1, ICU_RESET); io_wait();
    outb(ICU0+1, master); io_wait();
    outb(ICU1+1, slave); io_wait();
    outb(ICU0+1, 0x04); io_wait();
    outb(ICU1+1, 0x02); io_wait();
    outb(ICU0+1, 0x01); io_wait();
    outb(ICU1+1, 0x01); io_wait();
    outb(ICU0+1, 0xFB); io_wait();
    outb(ICU1+1, 0xFF);

    IRQmask = 0xFFFB;
}

void unmaskIRQ(int irq) {
    IRQmask &= ~(1 << irq);
    if(irq < 8)
	outb(ICU0+1, IRQmask & 0xFF);
    else
	outb(ICU1+1, IRQmask >> 8);
}


void maskIRQ(int irq) {
    IRQmask |= (1 << irq);
    if(irq < 8)
	outb(ICU0+1,IRQmask & 0xFF);
    else
	outb(ICU1+1,IRQmask >> 8);
}


void refreshIRQs(void) {
    outb(ICU0+1,IRQmask & 0xFF);
    outb(ICU1+1,IRQmask >> 8);
}


void registerIRQ(int irq, dword handler, int level) {
    interruptIDT(&IDT[32+irq], KERNEL_CS,handler, level);
    unmaskIRQ(irq);
}