int oldVal, int newVal) { return VM_ObjectModel.attemptAvailableBits(VM_Magic.addressAsObject(o),  VM_Word.fromInt(oldVal), VM_Word.fromInt(newVal));
VM_Word oldVal, VM_Word newVal) { return VM_ObjectModel.attemptAvailableBits(VM_Magic.addressAsObject(o), oldVal, newVal);
  public static boolean attemptAvailableBits(VM_Address o,                                             int oldVal, int newVal) {    return VM_ObjectModel.attemptAvailableBits(VM_Magic.addressAsObject(o),                                               // TODO: 64 bit broken                                               VM_Word.fromInt(oldVal),                                               VM_Word.fromInt(newVal));  }