irq.c

#include <system.h>

extern void _irq0();
extern void _irq1();
extern void _irq2();
extern void _irq3();
extern void _irq4();
extern void _irq5();
extern void _irq6();
extern void _irq7();
extern void _irq8();
extern void _irq9();
extern void _irq10();
extern void _irq11();
extern void _irq12();
extern void _irq13();
extern void _irq14();
extern void _irq15();

void *irq_routines[16] =
{
    0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0
};

void irq_install_handler(int32_t irq, void (*handler)(register_t *r))
{
    irq_routines[irq] = handler;
}

void irq_uninstall_handler(int32_t irq)
{
    irq_routines[irq] = 0;
}

void irq_remap(void)
{
    outportb(0x20, 0x11);
    outportb(0xA0, 0x11);
    outportb(0x21, 0x20);
    outportb(0xA1, 0x28);
    outportb(0x21, 0x04);
    outportb(0xA1, 0x02);
    outportb(0x21, 0x01);
    outportb(0xA1, 0x01);
    outportb(0x21, 0x0);
    outportb(0xA1, 0x0);
}

void irq_install()
{
    irq_remap();

    idt_set_gate(32, (unsigned)_irq0, 0x08, 0x8E);
    idt_set_gate(33, (unsigned)_irq1, 0x08, 0x8E);
    idt_set_gate(34, (unsigned)_irq2, 0x08, 0x8E);
    idt_set_gate(35, (unsigned)_irq3, 0x08, 0x8E);
    idt_set_gate(36, (unsigned)_irq4, 0x08, 0x8E);
    idt_set_gate(37, (unsigned)_irq5, 0x08, 0x8E);
    idt_set_gate(38, (unsigned)_irq6, 0x08, 0x8E);
    idt_set_gate(39, (unsigned)_irq7, 0x08, 0x8E);
    idt_set_gate(40, (unsigned)_irq8, 0x08, 0x8E);
    idt_set_gate(41, (unsigned)_irq9, 0x08, 0x8E);
    idt_set_gate(42, (unsigned)_irq10, 0x08, 0x8E);
    idt_set_gate(43, (unsigned)_irq11, 0x08, 0x8E);
    idt_set_gate(44, (unsigned)_irq12, 0x08, 0x8E);
    idt_set_gate(45, (unsigned)_irq13, 0x08, 0x8E);
    idt_set_gate(46, (unsigned)_irq14, 0x08, 0x8E);
    idt_set_gate(47, (unsigned)_irq15, 0x08, 0x8E);
}

void irq_handler(register_t *r)
{
    void (*handler)(register_t *r);

    handler = irq_routines[r->int_no - 32];
    if (handler)
    {
        handler(r);
    }

    if (r->int_no >= 40)
    {
        outportb(0xA0, 0x20);
    }

    outportb(0x20, 0x20);
}