os/idt.c

#include "idt.h"
#include "io.h"
#include "string.h"
#include <stdint.h>

#define IDT_ENTRIES 256

struct idt_entry
{
    uint16_t base_lo;
    uint16_t sel;
    uint8_t always0;
    uint8_t flags;
    uint16_t base_hi;
} __attribute__((packed));

struct idt_ptr
{
    uint16_t limit;
    uint32_t base;
} __attribute__((packed));

struct idt_entry idt[IDT_ENTRIES];
struct idt_ptr idtp;

void idt_set_gate(uint8_t num, uint32_t base, uint16_t sel, uint8_t flags)
{
    idt[num].base_lo = base & 0xFFFF;
    idt[num].base_hi = (base >> 16) & 0xFFFF;
    idt[num].sel = sel;
    idt[num].always0 = 0;
    idt[num].flags = flags | 0x60;
}

void idt_install()
{
    idtp.limit = (sizeof(struct idt_entry) * IDT_ENTRIES) - 1;
    idtp.base = (uint32_t)&idt;

    memset(&idt, 0, sizeof(struct idt_entry) * IDT_ENTRIES);

    idt_load();
}