make32
rbd = (struct rbd_struct *) make32(p->rfd_top->rbd_offset);
rbd = (struct rbd_struct *) make32(rbd->next);
p->rfd_top = (struct rfd_struct *) make32(p->rfd_top->next); /* step to next RFD */
rbds = (struct rbd_struct *) make32(rfds->rbd_offset);
rfds = (struct rfd_struct *) make32(rfds->next);