class osc {
public:
  void init();
};

class osc_one : public osc {
public:
  int32_t prev;

  void init() { prev = 0; }

  void render(int32_t *pOut, int32_t amp, uint32_t freq, uint32_t phase,
              float invfreq) {
    // out: pointer to s32 output buffer, adds values
    // amp: s32 amplitude
    int32_t a = (int)(invfreq * amp);
    int32_t _prev = prev;
    int i = BUFSIZE;
    while (i--) {
      int32_t out = *pOut;

      int32_t v2 = ___SMMUL(phase, phase);
      int32_t d = (v2 - _prev);
      out = __SMMLA(d, a, out);
      _prev = v2;
      phase += freq;

      *pOut++ = out;
    }
    prev = _prev;
  }
};

static const int n_octaves = 7;

class chroma {
  int phase;

public:
  osc_one octaves[n_octaves];

  void init() {
    phase = 0;
    int i;
    for (i = 0; i < n_octaves; i++) {
      octaves[i].init();
    }
  };

  void render(int freq, int32_t *out, int32_t *pAmp, uint32_t x) {
    pAmp += 24;
    phase += freq << 4;
    uint32_t p = phase;
    uint32_t f = freq;
    float invfreq = (1 << 25) / (float)freq;
    int i;
    for (i = 0; i < n_octaves; i++) {
      octaves[i].render(out, *pAmp, f, p + x, invfreq);
      pAmp += 12;
      p = p << 1;
      f = f << 1;
      invfreq = invfreq * 0.5f;
    }
  }
};

chroma chromas[12];

int i;

for (i = 0; i < 12; i++) {
  chromas[i].init();
}

int i;

// clear
for (i = 0; i < BUFSIZE; i++) {
  outlet_wave[i] = 0;
}

// sum into output buffer
for (i = 0; i < 12; i++) {
  chromas[i].render(attr_tuning.array[i] >> 3, &outlet_wave[0],
                    &attr_amplitudes.array[i],
                    (param_phase + inlet_phase) << 5);
}

// output gain
for (i = 0; i < BUFSIZE; i++) {
  outlet_wave[i] = outlet_wave[i] << 2;
}