#pragma once

#define KERNBASE 0x80000000
#define PGSIZE 0x1000
#define PHYSTOP 0x8000000 // 128 Mib

#define PGROUNDUP(sz) (((sz) + PGSIZE - 1) & ~(PGSIZE - 1))
#define PGROUNDDOWN(a) (((a)) & ~((uintptr_t)(PGSIZE - 1)))

#define NPDENTRIES 1024 // # directory entries per page directory
#define NPTENTRIES 1024 // # PTEs per page table

#define PTXSHIFT 12 // offset of PTX in a linear address
#define PDXSHIFT 22 // offset of PDX in a linear address

#define PXMASK 0x3FF

#ifndef __ASSEMBLER__
#include <stdint.h>
#define V2P(a) (((uintptr_t)(a)) - KERNBASE)
#define P2V(a) ((void *)(((uintptr_t)(a)) + KERNBASE))

// page directory index
#define PDX(va) (((uintptr_t)(va) >> PDXSHIFT) & PXMASK)

// page table index
#define PTX(va) (((uintptr_t)(va) >> PTXSHIFT) & PXMASK)

// Address in page table or page directory entry
#define PTE_ADDR(pte) ((uintptr_t)(pte) & ~0xFFF)
#endif

// Page table/directory entry flags.
#define PTE_P 0x001   // Present
#define PTE_W 0x002   // Writeable
#define PTE_U 0x004   // User
#define PTE_PWT 0x008 // Write-Through
#define PTE_PCD 0x010 // Cache-Disable
#define PTE_A 0x020   // Accessed
#define PTE_D 0x040   // Dirty
// entries of page tables don't have PS
#define PDE_PS 0x080 // Page Size