MAGIC_16M
base[MB_END(16)] = MAGIC_16M;
if (base[MB_END(32)] != MAGIC_32M || base[MB_END(16)] != MAGIC_16M) {
base[MB_END(16)] = MAGIC_16M;
if (base[MB_END(16)] != MAGIC_16M || base[MB_END(8)] != MAGIC_8M) {