UHCI_USBSTS
uint16 status = ReadReg16(UHCI_USBSTS);
WriteReg16(UHCI_USBSTS, status);
WriteReg16(UHCI_USBSTS, acknowledge);
ReadReg16(UHCI_USBCMD), ReadReg16(UHCI_USBSTS));
uint16 status = ReadReg16(UHCI_USBSTS);
ReadReg16(UHCI_USBSTS), ReadReg16(UHCI_FRNUM));