New class, replace synth_whitenoise_f32

Author: boblark

synth_UniformWhiteNoise_F32.cpp

@@ -0,0 +1,66 @@
+/*      synth_UniformWhiteNoise_F32.cpp
+
+   License: MIT License.  Use at your own risk.
+*/
+
+/* Audio Library for Teensy 3.X
+ * Copyright (c) 2014, Paul Stoffregen, paul@pjrc.com
+ *
+ * Development of this audio library was funded by PJRC.COM, LLC by sales of
+ * Teensy and Audio Adaptor boards.  Please support PJRC's efforts to develop
+ * open source software by purchasing Teensy or other PJRC products.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice, development funding notice, and this permission
+ * notice shall be included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "synth_UniformWhiteNoise_F32.h"
+#define I32_TO_F32_NORM_FACTOR (2.3283064E-10)
+#define Q31_TO_F32_NORM_FACTOR (4.6566129E-10)
+
+void AudioSynthUniformWhiteNoise_F32::update(void)
+   {
+   audio_block_f32_t *block_f32;
+   float32_t *pf;
+
+#if !defined(__ARM_ARCH_7EM__)
+   return]
+#else
+   if (level < 0.000001f)
+      return;     // special case, turn off update() if level==0.
+
+   block_f32 = AudioStream_F32::allocate_f32();
+   if (!block_f32)
+      return;
+   pf = block_f32->data;
+   for(int i=0;  i<block_f32->length;  i++)
+      {
+      uint64_t x = rnState;
+      x ^= x >> 12;
+      x ^= x << 25;
+      x ^= x >> 27;
+      rnState = x;
+      *pf++ = level*((Q31_TO_F32_NORM_FACTOR * (float32_t)((x * UINT64_C(2685821657736338717)) >> 32)) - 1.0f);
+      }
+
+   AudioStream_F32::transmit(block_f32);
+   AudioStream_F32::release(block_f32);
+#endif
+   }
+
+

synth_UniformWhiteNoise_F32.h

@@ -0,0 +1,80 @@
+/*       synth_UniformWhiteNoise_F32.h  ---  New July 2025
+   Generates a block of uniformly distributed, uncorrelated, white
+   noise of a range of (-level, +level) as set by amplitude(level)
+   with a default value of level = 0.0.  This replaces the class
+   synth_whitenoise_F32 and corrects the need for I16 memory as well
+   providing output that uses the full F32 mantissa of 24-bits.
+
+   Method is xor shift 64 credited to George Marsaglia.   See
+   https://en.wikipedia.org/wiki/Xorshift   and
+   https://forum.pjrc.com/index.php?threads/teensy-4-1-random-number-generator.61125
+   post 13 by #Nominal Animal.
+     Bob Larkin July 2025.  Thanks #grrrr
+
+	Derived from synth_whitenoise_F32 that was
+	extended by: Chip Audette, OpenAudio, Feb 2017
+	
+	License: MIT License.  Use at your own risk.
+*/
+/* Audio Library for Teensy 3.X
+ * Copyright (c) 2014, Paul Stoffregen, paul@pjrc.com
+ *
+ * Development of this audio library was funded by PJRC.COM, LLC by sales of
+ * Teensy and Audio Adaptor boards.  Please support PJRC's efforts to develop
+ * open source software by purchasing Teensy or other PJRC products.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice, development funding notice, and this permission
+ * notice shall be included in all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+// ** This does not support Teensy LC (KINETISL).  Teensy 3.x and 4.x OK.  **
+// Execution time 15 uSec for 128 size block on T4.x. 12 of these are
+// the conversionfrom uint32_t to F32 with offset for DC=0.
+
+#ifndef synth_uniform_white_noise_f32_h_
+#define synth_uniform_white_noise_f32_h_
+#include "Arduino.h"
+#include "AudioStream_F32.h"
+#include "utility/dspinst.h"
+
+class AudioSynthUniformWhiteNoise_F32 : public AudioStream_F32
+{
+//GUI: inputs:0, outputs:1 //this line used for automatic generation of GUI node
+//GUI: shortName:uniformwhitenoise  //this line used for automatic generation of GUI node
+public:
+	AudioSynthUniformWhiteNoise_F32() : AudioStream_F32(0, NULL) { setDefaultValues(); }
+	AudioSynthUniformWhiteNoise_F32(const AudioSettings_F32 &settings) :
+         AudioStream_F32(0, NULL) { setDefaultValues(); }
+	void setDefaultValues(void) {
+		level = 0.0f;
+		rnState = 1ULL + instance_count++;
+	}
+
+	void amplitude(float nL) {
+		if (nL < 0.0) nL = 0.0;
+      level = nL;
+	}
+
+	virtual void update(void);
+
+private:
+   float32_t level = 0.0f;
+	uint64_t rnState;
+	uint64_t instance_count=0ULL;
+};
+#endif