midictl_rpn_read
midictl_rpn_read(midictl *mc, uint_fast8_t, uint_fast16_t, uint_fast16_t);
w = midictl_rpn_read(&ms->ctl, chan, key, 2<<7);
mp = midictl_rpn_read(&ms->ctl, chan, key, 8192);
mp = midictl_rpn_read(&ms->ctl, chan, key, 64<<7) >> 7;