cycles_to_usec
xcnt_diff_us = cycles_to_usec(xcnt - shared_data->xcnt);
xcnt_diff_us = cycles_to_usec(timer_get_cycles() - shared_data->xcnt);
xcnt_diff_us = cycles_to_usec(xcnt - shared_data->xcnt);
xcnt_diff_us = cycles_to_usec(xcnt - shared_data->xcnt);