void uhci_show_qh(puhci_desc_t qh);
void uhci_show_td(puhci_desc_t td);
void uhci_show_td_queue(puhci_desc_t td);
void uhci_show_queue(puhci_desc_t qh);
void uhci_show_status(puhci_t s);
void beep(long freq);
void dump_urb (purb_t purb);