PG_PDE_CACHE
npde = opde & ~PG_PDE_CACHE;
if ((*pde & PG_PDE_CACHE) == cache_bits_pde) {
if ((*pde & PG_PDE_CACHE) != cache_bits_pde) {
mask = pg_nx | PG_G | PG_RW | PG_U | PG_PDE_CACHE;
attrs |= pde & (PG_G | PG_PDE_CACHE);