hackthelobby/libcaca/kernel/boot/pic.c

90 lines
1.9 KiB
C

/*
* libcaca Colour ASCII-Art library
* Copyright (c) 2006 Sam Hocevar <sam@hocevar.net>
* 2009 Jean-Yves Lamoureux <jylam@lnxscene.org>
* All Rights Reserved
*
* This library is free software. It comes without any warranty, to
* the extent permitted by applicable law. You can redistribute it
* and/or modify it under the terms of the Do What the Fuck You Want
* to Public License, Version 2, as published by Sam Hocevar. See
* http://www.wtfpl.net/ for more details.
*/
#include "klibc.h"
#define PIC_MASTER_ICW1 0x20
#define PIC_MASTER_ICW2 0x21
#define PIC_SLAVE_ICW1 0xA0
#define PIC_SLAVE_ICW2 0xA1
void init_pic(void)
{
/* MASTER */
outbp(PIC_MASTER_ICW1, 0x11); // Init 8259A-1
/* ICW2 - start vector = 32 */
outbp(PIC_MASTER_ICW2, 0x20); // IRQ 0-7 mapped to 0x20-0x27
/* IICW3 */
outbp(PIC_MASTER_ICW2, 0x04); // 8259A-1 has slave
/* ICW4 */
outbp(PIC_MASTER_ICW2, 0x01);
/* Int mask */
outbp(PIC_MASTER_ICW2, 0xFF);
/* SLAVE */
outbp(PIC_SLAVE_ICW1, 0x11);
/* ICW2 - start vector = 96 */
outbp(PIC_SLAVE_ICW2, 0x70);
/* ICW3 */
outbp(PIC_SLAVE_ICW2, 0x02);
/* ICW4 */
outbp(PIC_SLAVE_ICW2, 0x01);
/* Int Mask */
outbp(PIC_SLAVE_ICW2, 0xFF);
/* Unmask irqs */
outbp(0x21, 0xFD);
}
static unsigned int cached_irq_mask = 0xffff;
#define __byte(x,y) (((unsigned char *)&(y))[x])
#define cached_21 (__byte(0,cached_irq_mask))
#define cached_A1 (__byte(1,cached_irq_mask))
void disable_interrupt(char irq)
{
unsigned int mask = 1 << irq;
cached_irq_mask |= mask;
if (irq & 8)
{
outb(0xA1, cached_A1);
}
else
{
outb(0x21, cached_21);
}
}
void enable_interrupt(char irq)
{
unsigned int mask = ~(1 << irq);
cached_irq_mask &= mask;
if (irq & 8)
{
outb(0xA1, cached_A1);
}
else
{
outb(0x21, cached_21);
}
}