From b2e20804ca99f69909a77a03a450bf9ae707a2b7 Mon Sep 17 00:00:00 2001
From: Holger Wirtz <dcoredump@googlemail.com>
Date: Sat, 14 Mar 2020 18:04:28 +0100
Subject: [PATCH] Optimized the calculation funtion for the sound and got some
 CPU cycles more for sound calculation. This fixes also the too low output
 volume.

---
 MicroDexed.ino |  3 +--
 dexed.cpp      | 39 +++++----------------------------------
 2 files changed, 6 insertions(+), 36 deletions(-)

diff --git a/MicroDexed.ino b/MicroDexed.ino
index 2ea45ce..bfd2d36 100644
--- a/MicroDexed.ino
+++ b/MicroDexed.ino
@@ -258,12 +258,11 @@ void setup()
   pinMode(U8X8_CS_PIN, OUTPUT);
 #endif
 
-  delay(320); // necessary, because before no serial output is done :(
-
 #ifdef ENABLE_LCD_UI
   setup_ui();
 #else
 #ifdef DEBUG
+  delay(320); // necessary, because before no serial output is done :(
   Serial.println(F("NO LCD DISPLAY ENABLED!"));
 #endif
 #endif
diff --git a/dexed.cpp b/dexed.cpp
index ef560e2..4264000 100644
--- a/dexed.cpp
+++ b/dexed.cpp
@@ -111,7 +111,8 @@ void Dexed::deactivate(void)
 
 void Dexed::getSamples(uint16_t n_samples, int16_t* buffer)
 {
-  uint16_t i;
+  uint16_t i,j;
+  uint8_t note;
   float sumbuf[n_samples];
 
   if (refreshVoice)
@@ -121,7 +122,6 @@ void Dexed::getSamples(uint16_t n_samples, int16_t* buffer)
       if ( voices[i].live )
         voices[i].dx7_note->update(data, voices[i].midi_note, voices[i].velocity, voices[i].porta);
     }
-
     lfo.reset(data + 137);
     refreshVoice = false;
   }
@@ -139,37 +139,15 @@ void Dexed::getSamples(uint16_t n_samples, int16_t* buffer)
     int32_t lfovalue = lfo.getsample();
     int32_t lfodelay = lfo.getdelay();
 
-    for (uint8_t note = 0; note < max_notes; note++)
+    for (note = 0; note < max_notes; note++)
     {
       if (voices[note].live)
       {
         voices[note].dx7_note->compute(audiobuf.get(), lfovalue, lfodelay, &controllers);
 
-        for (uint8_t j = 0; j < _N_; ++j)
+        for (j = 0; j < _N_; ++j)
         {
-          int32_t val = audiobuf.get()[j];
-          val = val >> 4;
-#ifdef USE_TEENSY_DSP
-          int32_t clip_val = signed_saturate_rshift(val, 24, 9);
-#else
-          int32_t clip_val = val < -(1 << 24) ? 0x8000 : val >= (1 << 24) ? 0x7fff : val >> 9;
-#endif
-
-          float f = static_cast<float>(clip_val >> REDUCE_LOUDNESS) / 0x7fff;
-#if defined(REDUCE_LOUDNESS_FACTOR)
-          f *= REDUCE_LOUDNESS_FACTOR;
-#endif
-          if (f > 1.0)
-          {
-            f = 1.0;
-            overload++;
-          }
-          else if (f < -1.0)
-          {
-            f = -1.0;
-            overload++;
-          }
-          sumbuf[i + j] += f;
+          sumbuf[i + j] += static_cast<float>(signed_saturate_rshift(audiobuf.get()[j] >> 4, 24, 9)) / 0x8000;
           audiobuf.get()[j] = 0;
         }
       }
@@ -178,16 +156,9 @@ void Dexed::getSamples(uint16_t n_samples, int16_t* buffer)
 
 #ifdef USE_FX
   fx.process(sumbuf, n_samples);
-// #else
-//  arm_scale_f32(sumbuf, fx.getGain(), sumbuf, n_samples);
 #endif
 
-  //#ifdef USE_TEENSY_DSP
   arm_float_to_q15(sumbuf, buffer, AUDIO_BLOCK_SAMPLES);
-  //#else
-  //for (i = 0; i < n_samples; ++i)
-  //buffer[i] = static_cast<int16_t>(sumbuf[i] * 0x7fff);
-  //#endif
 }
 
 void Dexed::keydown(int16_t pitch, uint8_t velo) {