Akso - Audio DSP Platform

ldrive interp

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drives a phasor (saw-wave) for reading/writing data

Author: robert schirmer

License: BSD

Github: rbrt/testing/ldrive interp.axo

Inlets

frac32.positive offset inside the table

frac32.positive length of the area to index,or loop end

frac32.positive position inside range on reset

frac32.positive loopstart inside range

frac32.bipolar speed modulation

bool32 play

bool32.rising r2zero

bool32.rising reset to startpoint

Outlets

frac32buffer audio out

frac32buffer plaback phase in fraction of table

int32 loop count since reset

int32 playhead position inside loop in samples

int32 length of range in samples

int32 length of loop in samples

frac32.bipolar total speed

Parameters

frac32.s.map speed ,+ 64 normal speed forward, - 64 backward

Attributes

objref table

Declaration

int32_t index1;
int32_t index2;
int32_t index3;

bool r;
uint8_t shift;

int32_t t_speed;
int32_t loopstart;
int32_t reset;
uint32_t count;
bool add;

uint32_t max;
uint32_t offset;

Init

// set 'shift factor' for storing the recording length/the sync output
shift = (27 - attr_table.LENGTHPOW);

Control Rate

offset = ___SMMUL(inlet_offset, (attr_table.LENGTH << 5));

if (inlet_range == (1 << 27) - 1)
  max = ___SMMUL(inlet_range, (attr_table.LENGTH << 5)) + offset + 1;
else
  max = ___SMMUL(inlet_range, (attr_table.LENGTH << 5)) + offset;

loopstart = ___SMMUL(inlet_range, inlet_loopstart) << 5;
t_speed = (inlet_speed + param_speed) >> attr_table.LENGTHPOW;
add = inlet_range;

reset = (___SMMUL(inlet_range, inlet_startpoint) << 5);

if (inlet_r2start && (!r)) {
  index1 = reset;
  r = 1;
  count = 0;
}

if (inlet_r2zero && (!r)) {
  index1 = 0;
  r = 1;
  count = 0;
}

if ((!inlet_r2start) && (!inlet_r2zero))
  r = 0;

outlet_count = count;
outlet_spos = index2;
outlet_stotal = inlet_range >> shift;
outlet_sloop = (inlet_range - loopstart) >> shift;
outlet_speed = inlet_speed + param_speed;

Audio Rate

if (t_speed > 0) {
  if (index1 >= inlet_range) {
    index1 = loopstart;
    count += add;
  }
} else {
  if (index1 <= loopstart) {
    index1 = inlet_range;
    count += add;
  }
}

outlet_phase = __USAT(index1 + inlet_offset, 27);

// interpolated playback
index2 = outlet_phase >> shift;

if ((index2 + 1) < max)
  index3 = index2 + 1;
else
  index3 = offset;

int32_t y1 = attr_table.array[index2] << attr_table.GAIN;
int32_t y2 = attr_table.array[index3] << attr_table.GAIN;

int frac = (outlet_phase - (index2 << shift)) << (attr_table.LENGTHPOW + 3);
int32_t rr;
rr = ___SMMUL(y1, (1 << 30) - frac);
rr = ___SMMLA(y2, frac, rr);
outlet_wave = rr << 2;

if (inlet_play)
  index1 += t_speed;
else
  outlet_wave = 0;