/* * AudioSynthWaveformSine_F32 * * Created: Chip Audette (OpenAudio) Feb 2017 * Modeled on: AudioSynthWaveformSine from Teensy Audio Library * * Purpose: Create sine wave of given amplitude and frequency * * License: MIT License. Use at your own risk. * */ #include "synth_sine_f32.h" #include "utility/dspinst.h" // data_waveforms.c extern "C" { extern const int16_t AudioWaveformSine[257]; } void AudioSynthWaveformSine_F32::update(void) { audio_block_f32_t *block; uint32_t i, ph, inc, index, scale; int32_t val1, val2; static uint32_t block_length = 0; if (enabled) { if (magnitude) { block = allocate_f32(); if (block) { block_length = (uint32_t)block->length; ph = phase_accumulator; inc = phase_increment; for (i=0; i < block_length; i++) { index = ph >> 24; val1 = AudioWaveformSine[index]; val2 = AudioWaveformSine[index+1]; scale = (ph >> 8) & 0xFFFF; val2 *= scale; val1 *= 0x10000 - scale; #if defined(KINETISK) block->data[i] = (float) multiply_32x32_rshift32(val1 + val2, magnitude); #elif defined(KINETISL) block->data[i] = (float) ((((val1 + val2) >> 16) * magnitude) >> 16); #endif ph += inc; block->data[i] = block->data[i] / 32767.0f; // scale to float } phase_accumulator = ph; AudioStream_F32::transmit(block); AudioStream_F32::release(block); return; } } phase_accumulator += phase_increment * block_length; } }