As the standard jaguar controller can not be differentiated from an open circuit, the SNES controller has precedence. In other words the controller operation is mutually exclusive and the SNES controller has a higher priority on the control of the ouputs.

void sampleAndProcessControllerData(void) {

  // clear reports
  atariKeypad[0] = 0xff;
  atariKeypad[1] = 0xff;
  atariKeypad[2] = 0xff;
  atariKeypad[3] = 0xff;

  sampleJaguarController();
  if ( sampleSNESController() )
    processSnesSampleData();
  else
    processJaguarSampledData();
}