biquad_coefficients lpc;
biquad_coefficients bpc;
biquad_coefficients hpc;

biquad_state bs;
biquad_coefficients bc;

static __attribute__((noinline)) int32_t
biquad_dsp_sample(biquad_state *state, biquad_coefficients *coefs,
                  int32_t filterinput) {

  int32_t accu = ___SMMUL(coefs->cxn_0, filterinput);
  accu = ___SMMLA(coefs->cxn_1, state->filter_x_n1, accu);
  accu = ___SMMLA(coefs->cxn_2, state->filter_x_n2, accu);
  accu = ___SMMLS(coefs->cyn_1, state->filter_y_n1, accu);
  accu = ___SMMLS(coefs->cyn_2, state->filter_y_n2, accu);

  int32_t filteroutput;
  filteroutput = accu << 4;

  state->filter_x_n2 = state->filter_x_n1;
  state->filter_x_n1 = filterinput;
  state->filter_y_n2 = state->filter_y_n1;
  state->filter_y_n1 = filteroutput;

  return __SSAT(filteroutput, 28);
}

static __attribute__((noinline)) void
biquad_morph_coefs(biquad_coefficients *incoefs1, biquad_coefficients *incoefs2,
                   biquad_coefficients *outcoefs, int32_t morph) {
  outcoefs->cyn_1 = ___SMMLA(incoefs2->cyn_1 - incoefs1->cyn_1 << 2, morph << 3,
                             incoefs1->cyn_1);
  outcoefs->cyn_2 = ___SMMLA(incoefs2->cyn_2 - incoefs1->cyn_2 << 2, morph << 3,
                             incoefs1->cyn_2);
  outcoefs->cxn_0 = ___SMMLA(incoefs2->cxn_0 - incoefs1->cxn_0 << 2, morph << 3,
                             incoefs1->cxn_0);
  outcoefs->cxn_1 = ___SMMLA(incoefs2->cxn_1 - incoefs1->cxn_1 << 2, morph << 3,
                             incoefs1->cxn_1);
  outcoefs->cxn_2 = ___SMMLA(incoefs2->cxn_2 - incoefs1->cxn_2 << 2, morph << 3,
                             incoefs1->cxn_2);
}

biquad_clearstate(&bs);

int32_t freq;
MTOF(param_pitch + inlet_pitch, freq);
int32_t mode = __SSAT(inlet_mode + param_mode, 28);

if (mode > 0) // morph between bp and hp
{
  biquad_bp_coefs(&bpc, freq,
                  INT_MAX - (__USAT(inlet_reso + param_reso, 27) << 4));
  biquad_hp_coefs(&hpc, freq,
                  INT_MAX - (__USAT(inlet_reso + param_reso, 27) << 4));
  biquad_morph_coefs(&bpc, &hpc, &bc, mode);
} else // morph between lp and bp
{
  biquad_lp_coefs(&lpc, freq,
                  INT_MAX - (__USAT(inlet_reso + param_reso, 27) << 4));
  biquad_bp_coefs(&bpc, freq,
                  INT_MAX - (__USAT(inlet_reso + param_reso, 27) << 4));
  biquad_morph_coefs(&bpc, &lpc, &bc, -mode);
}

outlet_out = biquad_dsp_sample(&bs, &bc, inlet_in);