#if attr_location == 0
#define LOCATION
#else
#define LOCATION __attribute__((section(".sdram")))
#endif
static const uint32_t LENGTHPOW = (attr_buffsize);
static const uint32_t LENGTH = (1 << attr_buffsize);
static const uint32_t LENGTHMASK = ((1 << attr_buffsize) - 1);

int32_t *delayline;
int wptr;

static int32_t array_[attr_poly][LENGTH] LOCATION;
delayline = &array_[parent->polyIndex][0];

for (int i = 0; i < LENGTH; i++)
  delayline[i] = 0;
wptr = 0;

int32_t g2 = inlet_gain << 3;

int32_t time = ___SMMUL(inlet_time, inlet_timemod) + inlet_time;
int32_t readOffset_ls8 = ___SMMUL(LENGTH << 10, time << 3);

if (readOffset_ls8 < (8 << 8))
  readOffset_ls8 = (8 << 8); // never less delay than 8 samples

#if attr_interpol > 0
int32_t rint = readOffset_ls8 >> 8; // integral part of delay time
int32_t rfrac =
    readOffset_ls8 & 0x000000FF; // fractional part of delay time in Q8 notation
#endif

// pre-calculate coefficients for 3pt interpolation
#if attr_interpol == 2
// basic formula: y = ax^2 + bx + c
// a = 1/2*y3 - y2 + 1/2*y1
// b = -1/2*y3 + 2*y2 - 3/1*y1
// c = y1
// optimized formula (with c1..c3 = const for each block of samples):
// y = y1*c1 + y2*c2 + y3*c3
// c1 = 1 + 1/2*x^2 - 3/2*x
// c2 = -x^2 + 2x
// c3 = 1/2*x^2 - 1/2*x
int32_t x2 = (rfrac * rfrac); // x^2 in Q16 notation
// in Q16 notation
int32_t c1 = (1 << 16) + (x2 >> 1) - (rfrac << 7) - (rfrac << 8);
int32_t c2 = -x2 + (rfrac << 9);
int32_t c3 = (x2 >> 1) - (rfrac << 7);
#endif

// no interpolation
#if attr_interpol == 0
int32_t rptr = wptr - (readOffset_ls8 >> 8);
int32_t dout = delayline[rptr & LENGTHMASK];
// linear (2pt) interpolation
#elif attr_interpol == 1
int32_t rptr1 = wptr - rint;
int32_t rptr2 = rptr1 + 1;
int32_t dout1 = delayline[rptr2 & LENGTHMASK] >> 1;
int32_t dout2 = delayline[rptr1 & LENGTHMASK] >> 1;
int32_t dout = ___SMMLA(rfrac << 23, (dout2 - dout1) << 1, dout1) << 1;
// qubic (3pt) interpolation
#elif attr_interpol == 2
int32_t rptr1 = wptr - rint;
int32_t rptr2 = rptr1 + 1;
int32_t rptr3 = rptr1 + 2;

int32_t dout1 = delayline[rptr3 & LENGTHMASK];
int32_t dout2 = delayline[rptr2 & LENGTHMASK];
int32_t dout3 = delayline[rptr1 & LENGTHMASK];
int32_t douttmp1 = ___SMMUL(dout1, c1 << 14);
int32_t douttmp2 = ___SMMLA(dout2, c2 << 14, douttmp1);
int32_t dout = ___SMMLA(dout3, c3 << 14, douttmp2) << 2;
#endif

int32_t din = ___SMMLA(g2, dout, inlet_in >> 2) << 1;
delayline[wptr] = din;
outlet_out = ___SMMLS(g2, din, dout >> 1) << 2;
wptr = (wptr + 1) & LENGTHMASK;