#ifndef PAGING_H
#define PAGING_H

#define PAGE_SIZE 4096
#define BITS_PER_ROW 64

#include <stdint.h>
#include <limine.h>

void paging_init(struct limine_kernel_address_response* kaddr, struct limine_framebuffer* fb);

extern uint64_t hhdm_off;

#define PHYS_TO_VIRT(x) ((void*)((uintptr_t)(x) + hhdm_off))
#define VIRT_TO_PHYS(x) ((uintptr_t)(x) - hhdm_off)

// Stole it
#define ALIGN_UP(x, align)   (((x) + ((align) - 1)) & ~((align) - 1))
#define ALIGN_DOWN(x, align) ((x) & ~((align) - 1))
#define PAGE_ALIGN_DOWN(x) ((x) & ~0xFFFULL)

#define PML4_INDEX(x) (((x) >> 39) & 0x1FF)
#define PDPT_INDEX(x) (((x) >> 30) & 0x1FF)
#define PD_INDEX(x)   (((x) >> 21) & 0x1FF)
#define PT_INDEX(x)   (((x) >> 12) & 0x1FF)

// Page entry special bits
// Bits set on a parent (directory, table) fall back to their children
#define PTE_PRESENT     (1ULL << 0)
#define PTE_WRITABLE    (1ULL << 1)
#define PTE_USER        (1ULL << 2)
#define PTE_PWT         (1ULL << 3)
#define PTE_PCD         (1ULL << 4)
#define PTE_HUGE        (1ULL << 7)
#define PTE_NOEXEC      (1ULL << 63)

// Specified in linker.ld
#define KERNEL_BASE 0xFFFFFFFF80000000ULL

// 2 MB should be enough (as of now, the whole kernel ELF is around 75kb)
#define KERNEL_SIZE 0x200000

#endif