#define _PAGE_WRITETHRU 0x040 /* W: cache write-through */
#define _PAGE_DIRTY 0x080 /* C: page changed */
#define _PAGE_ACCESSED 0x100 /* R: page referenced */
-#define _PAGE_EXEC 0x200 /* software: i-cache coherency required */
#define _PAGE_RW 0x400 /* software: user write access allowed */
#define _PAGE_SPECIAL 0x800 /* software: Special page */