Add a multiplier (by rheslip)

Audio.h

 #include "play_sd_wav.h"
 #include "synth_tonesweep.h"
 #include "synth_waveform.h"
-
+#include "multiplier.h"
 
 // TODO: more audio processing objects....
 //  sine wave with frequency modulation (phase)

multiplier.cpp

+/* Audio Library for Teensy 3.X
+ * Copyright (c) 2014, Paul Stoffregen, paul@pjrc.com
+ * rheslip - modified Paul's mixer code to prduce a multiplier
+ * 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 "multiplier.h"
+
+// Multiply two inputs
+void AudioMultiplier2::update(void)
+{
+  audio_block_t *in, *out=NULL;
+  unsigned int i;
+
+  if (!out) {
+    out = receiveWritable(0); // first input - we'll use it as the output too
+    if (out) {
+      in = receiveReadOnly(1); // second input
+      if (in) {
+        int16_t * input1 = (int16_t *)out->data;
+        const int16_t * input2 = (int16_t *)in->data;
+        for (i=0; i < AUDIO_BLOCK_SAMPLES; ++i) {
+          int32_t tmp =*input1 * *input2++;
+//PAH change the scale to 15
+          *input1++= (int16_t)(tmp>>15);
+        }
+        release(in);
+      }
+    }
+  } 
+  if (out) {
+    transmit(out);
+    release(out);
+  }
+}
+
+
+

multiplier.h

+/* 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.
+ */
+
+#ifndef multiplier_h_
+#define multiplier_h_
+
+#include "AudioStream.h"
+
+class AudioMultiplier2 : 
+public AudioStream
+{
+public:
+  AudioMultiplier2(void) : 
+  AudioStream(2, inputQueueArray) {
+    //		for (int i=0; i<2; i++) multiplier[i] = 65536;
+  }
+  virtual void update(void);
+  /*	void gain(unsigned int channel, float gain) {
+   		if (channel >= 4) return;
+   		if (gain > 32767.0f) gain = 32767.0f;
+   		else if (gain < 0.0f) gain = 0.0f;
+   		multiplier[channel] = gain * 65536.0f; // TODO: proper roundoff?
+   	}
+   	*/
+private:
+  //	int32_t multiplier[2];
+  audio_block_t *inputQueueArray[2];
+};
+
+#endif
+

multiplier.md

+multiplier 140411
+	Multiplies two input waveforms, from channels zero and one.