int32_t _scaleVal;
int8_t _scale[12];
int8_t _nscale;
int32_t _note;
int32_t _tonic;
int32_t _offset;
int32_t _out;
int32_t _latch;

_note = 0;
_scaleVal = 0;
_nscale = 0;
_tonic = 0;
_offset = 0;
for (int i = 0; i < 12; i++) {
  _scale[i] = 0;
}

_latch = inlet_latch;
if (_scaleVal != param_b12) {
  // calculate new scale parameters as they changed
  // optimize for evaluation
  int x = 0;
  for (int i = 0; i < 12; i++) {
    if (param_b12 & (1 << i)) {
      _scale[x++] = i;
    }
  }
  _nscale = x;
}
if (_note != inlet_note || _offset != inlet_offset || _scaleVal != param_b12 ||
    _tonic != inlet_tonic) {
  _note = inlet_note;
  _tonic = inlet_tonic;
  _offset = inlet_offset;
  _scaleVal = param_b12;
  int mn = (inlet_note >> 21) + 64 - _offset;
  int8_t oct = mn / _nscale;
  int8_t n = mn % _nscale;
  _out = ((oct * 12 + _scale[n] + _tonic) - 64) << 21;
}
outlet_note = _out;

if (_latch && (status == MIDI_NOTE_ON + attr_midichannel) && (data2)) {
  int16_t note = data1 % 12;
  int16_t mask = 1 << note;
  int16_t nval = _scaleVal ^ mask;
  PExParameterChange(&parent->PExch[PARAM_INDEX_attr_legal_name_b12], nval,
                     0xFFFD);
}