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typedef struct
{
	u32int present		: 1;
	u32int rw			: 1; // read-write
	u32int user			: 1;
	u32int writethrough	: 1;
	u32int cachedisable	: 1;
	u32int accessed		: 1;
	u32int alwayszero	: 1;
	u32int size			: 1; // 0 = 4-kB, 1 = 4-mB
	u32int ignored		: 1;
	u32int available	: 3;
	u32int address		: 20;
} page_dirent_t;

Code: Select all

typedef struct
{
	u32int present		: 1;
	u32int rw			: 1; // read-write
	u32int user			: 1;
	u32int writethrough	: 1;
	u32int cachedisable	: 1;
	u32int accessed		: 1;
	u32int dirty		: 1;
	u32int alwayszero	: 1;
	u32int global		: 1;
	u32int available	: 3;
	u32int address		: 20;
} page_t;

Code: Select all

typedef struct page
{
    u32int present    : 1;   // Page present in memory
    u32int rw         : 1;   // Read-only if clear, readwrite if set
    u32int user       : 1;   // Supervisor level only if clear
    u32int accessed   : 1;   // Has the page been accessed since last refresh?
    u32int dirty      : 1;   // Has the page been written to since last refresh?
    u32int unused     : 7;   // Amalgamation of unused and reserved bits
    u32int frame      : 20;  // Frame address (shifted right 12 bits)
} page_t;

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

typedef struct page_directory
{
    /**
       Array of pointers to pagetables.
    **/
    page_table_t *tables[1024];
    /**
       Array of pointers to the pagetables above, but gives their *physical*
       location, for loading into the CR3 register.
    **/
    u32int tablesPhysical[1024];

    /**
       The physical address of tablesPhysical. This comes into play
       when we get our kernel heap allocated and the directory
       may be in a different location in virtual memory.
    **/
    u32int physicalAddr;
} page_directory_t;