case MARK:
case MARK_GREY: if (VM.VerifyAssertions) VM._assert(SimpleRCHeader.isLiveRC(object)); SimpleRCHeader.decRC(object); markGrey(object);
  public final VM_Address traceObject(VM_Address object, boolean root)    throws VM_PragmaInline {    switch (phase) {    case PROCESS:        incRC(object);      if (root)	VM_Interface.getPlan().addToRootSet(object);       break;    case DECREMENT:      VM_Interface.getPlan().addToDecBuf(object);       break;    case MARK://       if (SimpleRCHeader.isPurple(object))// 	decRC(object);      break;    case SCAN:      if (SimpleRCHeader.isPurple(object))	incRC(object);      break;    default:      if (VM.VerifyAssertions) VM._assert(false);    }    return object;  }