return ((addr.toInt()) + (LazyMmapper.MMAP_CHUNK_SIZE - 1)) >>> LazyMmapper.LOG_MMAP_CHUNK_SIZE;
VM_Word chunk = addr.add(LazyMmapper.MMAP_CHUNK_SIZE - 1).toWord().rshl(LazyMmapper.LOG_MMAP_CHUNK_SIZE); return chunk.toInt();
  public static int addressToMmapChunksUp (VM_Address addr) {    return ((addr.toInt()) + (LazyMmapper.MMAP_CHUNK_SIZE - 1)) >>> LazyMmapper.LOG_MMAP_CHUNK_SIZE;  }