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66 lines
1.3 KiB
66 lines
1.3 KiB
8 years ago
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/*
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* AudioSynthWaveformSine_F32
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*
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* Created: Chip Audette (OpenAudio) Feb 2017
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* Modeled on: AudioSynthWaveformSine from Teensy Audio Library
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*
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* Purpose: Create sine wave of given amplitude and frequency
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*
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* License: MIT License. Use at your own risk.
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*
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*/
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#include "synth_sine_f32.h"
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#include "utility/dspinst.h"
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// data_waveforms.c
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extern "C" {
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extern const int16_t AudioWaveformSine[257];
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}
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void AudioSynthWaveformSine_F32::update(void)
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{
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audio_block_f32_t *block;
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uint32_t i, ph, inc, index, scale;
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int32_t val1, val2;
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if (magnitude) {
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block = allocate_f32();
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if (block) {
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ph = phase_accumulator;
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inc = phase_increment;
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for (i=0; i < AUDIO_BLOCK_SAMPLES; i++) {
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index = ph >> 24;
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val1 = AudioWaveformSine[index];
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val2 = AudioWaveformSine[index+1];
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scale = (ph >> 8) & 0xFFFF;
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val2 *= scale;
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val1 *= 0x10000 - scale;
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#if defined(KINETISK)
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block->data[i] = (float) multiply_32x32_rshift32(val1 + val2, magnitude);
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#elif defined(KINETISL)
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block->data[i] = (float) ((((val1 + val2) >> 16) * magnitude) >> 16);
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#endif
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ph += inc;
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block->data[i] = block->data[i] / 32768.0f; // scale to float
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}
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phase_accumulator = ph;
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AudioStream_F32::transmit(block);
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AudioStream_F32::release(block);
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return;
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}
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}
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phase_accumulator += phase_increment * AUDIO_BLOCK_SAMPLES;
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}
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