Akso - Audio DSP Platform

tri_ph_b

$\text{[math]}$

Triangle wave LFO, bipolar, pitch, phase and reset inputs

Author: Are Leistad

License: BSD

Github: drj/lfo/triangle.axo

IO Variants: 2

Variant: 1

Inlets

frac32.bipolar Pitch input

frac32.bipolar phase input

bool32.rising Reset phase

Outlets

frac32.bipolar Triangle wave

Parameters

frac32.s.map.lfopitch pitch

Declaration

uint32_t phase;
uint32_t old_reset;
__attribute__((always_inline)) __STATIC_INLINE int32_t ___ABS(int32_t op1) {
  int32_t result;
  __ASM volatile("movs  %0, %1\n"
                 "it    mi\n"
                 "rsbmi %0, %0, #0"
                 : "=r"(result)
                 : "r"(op1));
  return (result);
};

Init

phase = 0;
old_reset = 0;

Control Rate

if (inlet_reset && !old_reset) {
  phase = 0;
} else {
  int32_t freq;
  MTOFEXTENDED(param_pitch + inlet_pitch, freq);
  phase += freq >> 2;
}
old_reset = inlet_reset;

int32_t saw = ((phase + (inlet_phase << 4)) >> 4) - (1 << 27);
outlet_tri = (1 << 27) - ___ABS(saw << 1);

Variant: 2