gdt.h

Go to the documentation of this file.

 
#pragma once
 
#include "stdint.h"
 
enum gdt_bits_t {
    GDT_PRESENT = 128U,
    GDT_KERNEL = 0U,
    GDT_USER = 96U,
    GDT_S = 16U,
    GDT_EX = 8U,
    GDT_DC = 4U,
    GDT_RW = 2U,
    GDT_AC = 1U,
    GDT_CODE = (GDT_S | GDT_EX),
    GDT_DATA = (GDT_S | GDT_RW),
    GDT_GRANULARITY = 128U,
    GDT_OPERAND_SIZE = 64U,
};
 
#define IDT_PADDING 14U // `0b00001110U
 
typedef struct gdt_descriptor_t {
    uint16_t limit_low;
    uint16_t base_low;
    uint8_t base_middle;
    uint8_t access;
    uint8_t granularity;
    uint8_t base_high;
} __attribute__((packed)) gdt_descriptor_t;
 
typedef struct gdt_pointer_t {
    uint16_t limit;
    uint32_t base;
} __attribute__((packed)) gdt_pointer_t;
 
void init_gdt(void);
 
void gdt_set_gate(uint8_t index, uint32_t base, uint32_t limit, uint8_t access, uint8_t granul);