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66 lines
2.3 KiB
66 lines
2.3 KiB
/* synth_UniformWhiteNoise_F32.cpp
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License: MIT License. Use at your own risk.
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*/
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/* 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 "synth_UniformWhiteNoise_F32.h"
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#define I32_TO_F32_NORM_FACTOR (2.3283064E-10)
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#define Q31_TO_F32_NORM_FACTOR (4.6566129E-10)
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void AudioSynthUniformWhiteNoise_F32::update(void)
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{
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audio_block_f32_t *block_f32;
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float32_t *pf;
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#if !defined(__ARM_ARCH_7EM__)
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return]
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#else
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if (level < 0.000001f)
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return; // special case, turn off update() if level==0.
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block_f32 = AudioStream_F32::allocate_f32();
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if (!block_f32)
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return;
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pf = block_f32->data;
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for(int i=0; i<block_f32->length; i++)
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{
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uint64_t x = rnState;
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x ^= x >> 12;
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x ^= x << 25;
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x ^= x >> 27;
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rnState = x;
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*pf++ = level*((Q31_TO_F32_NORM_FACTOR * (float32_t)((x * UINT64_C(2685821657736338717)) >> 32)) - 1.0f);
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}
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AudioStream_F32::transmit(block_f32);
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AudioStream_F32::release(block_f32);
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#endif
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}
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