bsnes-libretro-cplusplus98/snes/controller/multitap/multitap.cpp

#ifdef CONTROLLER_CPP

uint2 Multitap::data() {
  if(latched) return 2;  //multitap detection
  unsigned index, port1, port2;

  if(iobit()) {
    index = counter1;
    if(index >= 16) return 3;
    counter1++;
    port1 = 0;  //controller 1
    port2 = 1;  //controller 2
  } else {
    index = counter2;
    if(index >= 16) return 3;
    counter2++;
    port1 = 2;  //controller 3
    port2 = 3;  //controller 4
  }

  bool data1 = system.interface->input_poll(port, Input::Device::Multitap, port1, index);
  bool data2 = system.interface->input_poll(port, Input::Device::Multitap, port2, index);
  return (data2 << 1) | (data1 << 0);
}

void Multitap::latch(bool data) {
  if(latched == data) return;
  latched = data;
  counter1 = 0;
  counter2 = 0;
}

Multitap::Multitap(bool port) : Controller(port) {
  latched = 0;
  counter1 = 0;
  counter2 = 0;
}

#endif