NUM_USER_PGDIR_ENTS
NUM_USER_PGDIR_ENTS * sizeof(page_directory_entry));
memset(page_hole_pgdir + FIRST_USER_PGDIR_ENT, 0, sizeof(page_directory_entry) * NUM_USER_PGDIR_ENTS);
sizeof(page_directory_entry) * NUM_USER_PGDIR_ENTS);
NUM_USER_PGDIR_ENTS * sizeof(page_directory_entry));
NUM_USER_PGDIR_ENTS * sizeof(page_directory_entry));
sizeof(page_directory_entry) * NUM_USER_PGDIR_ENTS);
NUM_USER_PGDIR_ENTS * sizeof(page_directory_entry));