#include "pic.h"
#include "io.h"

#define PIC1_COMMAND 0x20
#define PIC1_DATA    0x21
#define PIC2_COMMAND 0xA0
#define PIC2_DATA    0xA1

#define ICW1_INIT    0x10
#define ICW1_IC4     0x01
#define ICW4_8086    0x01

void pic_remap(uint8_t master_offset, uint8_t slave_offset) {
    uint8_t a1 = inb(PIC1_DATA);
    uint8_t a2 = inb(PIC2_DATA);

    outb(PIC1_COMMAND, ICW1_INIT | ICW1_IC4);
    io_wait();
    outb(PIC2_COMMAND, ICW1_INIT | ICW1_IC4);
    io_wait();

    outb(PIC1_DATA, master_offset);
    io_wait();
    outb(PIC2_DATA, slave_offset);
    io_wait();

    outb(PIC1_DATA, 4);
    io_wait();
    outb(PIC2_DATA, 2);
    io_wait();

    outb(PIC1_DATA, ICW4_8086);
    io_wait();
    outb(PIC2_DATA, ICW4_8086);
    io_wait();

    outb(PIC1_DATA, a1);
    outb(PIC2_DATA, a2);
}

void pic_set_mask(uint8_t irq_line) {
    uint16_t port;
    if (irq_line < 8) {
        port = PIC1_DATA;
    } else {
        port = PIC2_DATA;
        irq_line -= 8;
    }
    uint8_t value = inb(port) | (1 << irq_line);
    outb(port, value);
}

void pic_clear_mask(uint8_t irq_line) {
    uint16_t port;
    if (irq_line < 8) {
        port = PIC1_DATA;
    } else {
        port = PIC2_DATA;
        irq_line -= 8;
    }
    uint8_t value = inb(port) & ~(1 << irq_line);
    outb(port, value);
}