#pragma once

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

typedef struct page
{
    uint32_t present    : 1; // page present in memory
    uint32_t rw         : 1; // ro if clear, rw if set
    uint32_t user       : 1; // supervisor level only if clear
    uint32_t accessed   : 1; // has been accessed since last referesh
    uint32_t dirty      : 1; // has been written to since last refresh
    uint32_t unused     : 7; // reserved and unused bits
    uint32_t frame      : 20; // frame address (right shift 12 bits)
} page_t;

typedef struct page_table
{
    page_t pages[1024];
} page_table_t;

typedef struct
{
    // array of pointers to pagetables
    page_table_t *tables[1024];
    // array of pointers to tables above but at the *physical* loc
    // so they can be loaded into cr3
    uint32_t tablesPhysical[1024];

    uint32_t physicalAddr;
} page_directory_t;

// sets up paging
void initialize_paging(void);

// causes the specified page directory to be loaded
// into the cr3 register
void switch_page_directory(page_directory_t *new);

// retrieves a pointer to the page requires
// if make == 1, if the pagetable in which page
// should reside inst there create it
page_t *get_page(uint32_t address, int make, page_directory_t *dir);

// handler for page faults
void page_fault(registers_t *regs);