// the chip implementation calls this whenever data is written outside
// of the chip; our responsibility is to pass the written data on to any consumers
protected virtual void ymfm_external_write(access_class type, uint32_t address, uint8_t data)
{
}
// the chip implementation calls this whenever data is read from outside
// of the chip; our responsibility is to provide the data requested
protected virtual uint8_t ymfm_external_read(access_class type, uint32_t address)
{
return(0);
}
