k-chow/k/idt.c

#include "idt.h"

static struct idt idt = { 0 };

void handle_interrupt()
{
    return;
}

struct idt_entry create_idt_entry(uint32_t offset,
                                  struct segment_selector selector)
{
    struct idt_entry res = { 0 };

    res.selector = selector;
    res.offset_1 = offset & 0xffff;
    res.offset_2 = (offset >> 16) & 0xffff;

    res.type = INTERRUPT_TYPE;
    res.size = 1;
    res.desc_priv = 0;
    res.present = 1;

    return res;
}

static void create_idt(void)
{
    struct segment_selector selector;
    selector.rpl = 0;
    selector.table_indicator = 0;
    selector.index = KERNEL_CS_INDEX;
    for (int i = 0; i < IDT_NB_ENTRIES; ++i)
    {
        struct idt_entry entry = create_idt_entry((uint32_t)&handle_interrupt,
                                                  selector);
        idt.entries[i] = entry;
    }
}


static void load_idt(void)
{
    struct idt_r idtr;
    idtr.addr = (uint32_t)&idt;
    idtr.limit = IDT_SIZE - 1;

    asm volatile("lidt %0\n"
                 :
                 : "m" (idtr)
                 : "memory");
}

void init_idt(void)
{
    create_idt();
    load_idt();
}