110 lines
3.2 KiB
C++
Executable file
110 lines
3.2 KiB
C++
Executable file
/* Audio Library for Teensy 3.X
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* Copyright (c) 2014, Paul Stoffregen, paul@pjrc.com
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*
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* Development of this audio library was funded by PJRC.COM, LLC by sales of
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* Teensy and Audio Adaptor boards. Please support PJRC's efforts to develop
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* open source software by purchasing Teensy or other PJRC products.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice, development funding notice, and this permission
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* notice shall be included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include <Arduino.h>
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#include "synth_dc.h"
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void AudioSynthWaveformDc::update(void)
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{
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audio_block_t *block;
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uint32_t *p, *end, val;
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int32_t count, t1, t2, t3, t4;
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block = allocate();
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if (!block) return;
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p = (uint32_t *)(block->data);
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end = p + AUDIO_BLOCK_SAMPLES/2;
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if (state == 0) {
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// steady DC output, simply fill the buffer with fixed value
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val = pack_16t_16t(magnitude, magnitude);
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do {
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*p++ = val;
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*p++ = val;
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*p++ = val;
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*p++ = val;
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*p++ = val;
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*p++ = val;
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*p++ = val;
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*p++ = val;
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} while (p < end);
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} else {
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// transitioning to a new DC level
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//count = (target - magnitude) / increment;
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count = substract_int32_then_divide_int32(target, magnitude, increment);
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if (count >= AUDIO_BLOCK_SAMPLES) {
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// this update will not reach the target
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do {
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magnitude += increment;
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t1 = magnitude;
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magnitude += increment;
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t1 = pack_16t_16t(magnitude, t1);
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magnitude += increment;
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t2 = magnitude;
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magnitude += increment;
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t2 = pack_16t_16t(magnitude, t2);
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magnitude += increment;
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t3 = magnitude;
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magnitude += increment;
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t3 = pack_16t_16t(magnitude, t3);
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magnitude += increment;
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t4 = magnitude;
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magnitude += increment;
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t4 = pack_16t_16t(magnitude, t4);
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*p++ = t1;
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*p++ = t2;
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*p++ = t3;
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*p++ = t4;
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} while (p < end);
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} else {
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// this update reaches the target
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while (count >= 2) {
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count -= 2;
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magnitude += increment;
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t1 = magnitude;
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magnitude += increment;
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t1 = pack_16t_16t(magnitude, t1);
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*p++ = t1;
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}
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if (count) {
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t1 = pack_16t_16t(target, magnitude + increment);
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*p++ = t1;
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}
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magnitude = target;
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state = 0;
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val = pack_16t_16t(magnitude, magnitude);
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while (p < end) {
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*p++ = val;
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}
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}
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}
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transmit(block);
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release(block);
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}
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