public void iterator(VM_Address start, VM_Address end) { debug(2, "Iterating from ", start); debug(2, "to ", end);   iterPage_ = addressToPage(start); iterSlot_ = addressToSlot(start); iterWord_ = addressToWord(start); iterBit_ = addressToBit(start);  if (VM_Interface.VerifyAssertions) VM_Interface._assert(start == bitmapToAddress(iterPage_, iterSlot_, iterWord_, iterBit_));  iterEnd_ = end; iterPageEnd_ = addressToPage(end);  advanceIterator(false); }
public void iterator(VM_Address start, VM_Address end) {}
  public void iterator(VM_Address start, VM_Address end) {      debug(2, "Iterating from ", start);      debug(2, "to ", end);      // set boundaries of search space      iterPage_ = addressToPage(start);      iterSlot_ = addressToSlot(start);      iterWord_ = addressToWord(start);      iterBit_ = addressToBit(start);            if (VM_Interface.VerifyAssertions)        VM_Interface._assert(start == bitmapToAddress(iterPage_, iterSlot_, iterWord_, iterBit_));            iterEnd_ = end;      iterPageEnd_ = addressToPage(end);      advanceIterator(false);  }