x = pa[k - 2]; x->trb_color = TRB_RED; y->trb_color = TRB_BLACK; x->trb_link[0] = y->trb_link[1]; y->trb_link[1] = x; pa[k - 3]->trb_link[da[k - 3]] = y; if (y->trb_tag[1] == TRB_THREAD) { y->trb_tag[1] = TRB_CHILD; x->trb_tag[0] = TRB_THREAD; x->trb_link[0] = y; }