libcaca/kernel/boot/pic.c

#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);
    }

}