k-tana-zero/k/idt.h

#ifndef IDT_H
#define IDT_H

#include <stdint.h>
#include "gdt.h"
#include "isr.h"

#define IDT_NB_ENTRIES 34
#define IDT_SIZE (IDT_NB_ENTRIES * sizeof(struct idt_entry))

#define INTEL_DEFINED 21
#define INTEL_UNUSED  31

#define INTERRUPT_TYPE 0x6
#define TRAP_TYPE      0x7

struct idt_entry
{
    uint16_t offset_1   : 16;   // 16 lsb of isr address
    struct segment_selector selector;

    uint8_t zero_1      : 8;    // unused, set to 0
    uint8_t type        : 3;    // gate type
    uint8_t size        : 1;    // 0 => 16-bits     1 => 32-bits
    uint8_t zero_2      : 1;    // set to 0 for interrupt and trap gates
    uint8_t desc_priv   : 2;    // descriptor privilege
    uint8_t present     : 1;    // always 1

    uint16_t offset_2   : 16;   // 16 msb of isr address
} __attribute__ ((packed));

struct idt
{
    struct idt_entry entries[IDT_NB_ENTRIES];
};

struct idt_r
{
    uint16_t limit;  // total size of the IDT - 1 in bytes
    uint32_t addr;   // base address of the IDT
} __attribute__ ((packed));

// This struct is used to get int_code and err_code pushed to the stack
// by the isr.
struct int_args
{
    uint32_t int_code;
    uint32_t err_code;
} __attribute__ ((packed));

// This struct is used to know how to fill the idt entries
struct idt_entry_info
{
    void (*isr)(void);  // function pointer on interrupt service routine (isr)
    uint32_t type;      // gate type
};

void init_idt(void);
void handle_interrupt(struct int_args *args);

#endif  /* !IDT_H */