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#include "pic.h"
#include <sys/control.h>
#include <sys/io.h>
#define PIC1 0x20
#define PIC2 0xa0
#define DATA 1
// initialization
#define ICW1_INIT 0x10
// TODO
#define ICW1_ICW4 0x01
// 8086/88 mode
#define ICW4_8086 0x01
void
pic_init()
{
outb(ICW1_INIT | ICW1_ICW4, PIC1);
outb(ICW1_INIT | ICW1_ICW4, PIC2);
outb(0x20, PIC1 + DATA); // offset 0x20
outb(0x28, PIC2 + DATA); // offset 0x28
outb(0x04, PIC1 + DATA); // tell master pic there is a slave pic
outb(0x02, PIC2 + DATA); // tell slave pic its cascade identity
outb(ICW4_8086, PIC1 + DATA);
outb(ICW4_8086, PIC2 + DATA);
// PIC masks
outb(0xff, PIC1 + DATA);
outb(0xff, PIC2 + DATA);
}
void
pic_enable()
{
unsigned char mask1 = 0xff;
mask1 &= ~(1 << 0); // irq0 timer
mask1 &= ~(1 << 1); // irq1 keyboard
mask1 &= ~(1 << 2); // irq1 cascade
outb(mask1, PIC1 + DATA);
unsigned char mask2 = 0xff;
mask2 &= ~(1 << 4); // irq12 mouse
outb(mask2, PIC2 + DATA);
enable_interrupts();
}
void
pic_clear(unsigned char irq)
{
outb(0x20, PIC1);
if (irq >= 8) outb(0x20, PIC2);
}
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