From f7bd06c4eb4dd151065dc81c6506e2ed33e33744 Mon Sep 17 00:00:00 2001
From: tildearrow <tildearrow@protonmail.com>
Date: Thu, 24 Feb 2022 16:16:02 -0500
Subject: [PATCH 1/5] yay ADPCM-A and QSound work again!

---
 src/engine/engine.cpp                   | 36 ++++++++++++-------------
 src/engine/engine.h                     |  8 +++---
 src/engine/platform/ym2610Interface.cpp | 16 ++++++-----
 src/engine/sample.cpp                   | 18 +++++++------
 src/engine/vgmOps.cpp                   |  8 +++---
 src/gui/gui.cpp                         |  4 +--
 6 files changed, 47 insertions(+), 43 deletions(-)

diff --git a/src/engine/engine.cpp b/src/engine/engine.cpp
index 9dee6ecfe..29c293e86 100644
--- a/src/engine/engine.cpp
+++ b/src/engine/engine.cpp
@@ -444,46 +444,45 @@ void DivEngine::renderSamples() {
   sPreview.sample=-1;
   sPreview.pos=0;
 
+  // step 1: render samples
   for (int i=0; i<song.sampleLen; i++) {
     song.sample[i]->render();
   }
 
-  /*
-  // step 3: allocate ADPCM samples
-  if (adpcmMem==NULL) adpcmMem=new unsigned char[16777216];
+  // step 2: allocate ADPCM-A samples
+  if (adpcmAMem==NULL) adpcmAMem=new unsigned char[16777216];
 
   size_t memPos=0;
   for (int i=0; i<song.sampleLen; i++) {
     DivSample* s=song.sample[i];
-    if ((memPos&0xf00000)!=((memPos+s->adpcmRendLength)&0xf00000)) {
+    int paddedLen=(s->lengthA+255)&(~0xff);
+    if ((memPos&0xf00000)!=((memPos+paddedLen)&0xf00000)) {
       memPos=(memPos+0xfffff)&0xf00000;
     }
     if (memPos>=16777216) {
       logW("out of ADPCM memory for sample %d!\n",i);
       break;
     }
-    if (memPos+s->adpcmRendLength>=16777216) {
-      memcpy(adpcmMem+memPos,s->adpcmRendData,16777216-memPos);
+    if (memPos+paddedLen>=16777216) {
+      memcpy(adpcmAMem+memPos,s->dataA,16777216-memPos);
       logW("out of ADPCM memory for sample %d!\n",i);
     } else {
-      memcpy(adpcmMem+memPos,s->adpcmRendData,s->adpcmRendLength);
+      memcpy(adpcmAMem+memPos,s->dataA,paddedLen);
     }
-    s->rendOff=memPos;
-    memPos+=s->adpcmRendLength;
+    s->offA=memPos;
+    memPos+=paddedLen;
   }
-  adpcmMemLen=memPos+256;
+  adpcmAMemLen=memPos+256;
 
   // step 4: allocate qsound pcm samples
   if (qsoundMem==NULL) qsoundMem=new unsigned char[16777216];
 
-  memset(qsoundMem, 0, 16777216);
-
   memPos=0;
   for (int i=0; i<song.sampleLen; i++) {
     DivSample* s=song.sample[i];
-    int length = s->rendLength;
-    if (length > 65536-16) {
-      length = 65536-16;
+    int length=s->length8;
+    if (length>65536-16) {
+      length=65536-16;
     }
     if ((memPos&0xff0000)!=((memPos+length)&0xff0000)) {
       memPos=(memPos+0xffff)&0xff0000;
@@ -494,19 +493,18 @@ void DivEngine::renderSamples() {
     }
     if (memPos+length>=16777216) {
       for (unsigned int i=0; i<16777216-(memPos+length); i++) {
-        qsoundMem[(memPos + i) ^ 0x8000] = s->rendData[i] >> ((s->depth == 16) ? 8 : 0);
+        qsoundMem[(memPos+i)^0x8000]=s->data8[i];
       }
       logW("out of QSound PCM memory for sample %d!\n",i);
     } else {
       for (int i=0; i<length; i++) {
-        qsoundMem[(memPos + i) ^ 0x8000] = s->rendData[i] >> ((s->depth == 16) ? 8 : 0);
+        qsoundMem[(memPos+i)^0x8000]=s->data8[i];
       }
     }
-    s->rendOffQsound=memPos ^ 0x8000;
+    s->offQSound=memPos^0x8000;
     memPos+=length+16;
   }
   qsoundMemLen=memPos+256;
-  */
 }
 
 void DivEngine::createNew() {
diff --git a/src/engine/engine.h b/src/engine/engine.h
index 96594a3ca..c02416996 100644
--- a/src/engine/engine.h
+++ b/src/engine/engine.h
@@ -621,8 +621,8 @@ class DivEngine {
     // terminate the engine.
     bool quit();
 
-    unsigned char* adpcmMem;
-    size_t adpcmMemLen;
+    unsigned char* adpcmAMem;
+    size_t adpcmAMemLen;
     unsigned char* adpcmBMem;
     size_t adpcmBMemLen;
     unsigned char* qsoundMem;
@@ -680,8 +680,8 @@ class DivEngine {
       totalProcessed(0),
       oscBuf{NULL,NULL},
       oscSize(1),
-      adpcmMem(NULL),
-      adpcmMemLen(0),
+      adpcmAMem(NULL),
+      adpcmAMemLen(0),
       adpcmBMem(NULL),
       adpcmBMemLen(0),
       qsoundMem(NULL),
diff --git a/src/engine/platform/ym2610Interface.cpp b/src/engine/platform/ym2610Interface.cpp
index 8d53e48ce..45fb5288b 100644
--- a/src/engine/platform/ym2610Interface.cpp
+++ b/src/engine/platform/ym2610Interface.cpp
@@ -22,12 +22,16 @@
 #include "../engine.h"
 
 uint8_t DivYM2610Interface::ymfm_external_read(ymfm::access_class type, uint32_t address) {
-  //printf("wants to read from %x\n",address);
-  if (type!=ymfm::ACCESS_ADPCM_A) return 0;
-  return parent->adpcmMem[address&0xffffff];
-  /*if (12*sampleBank+(address>>16)>=parent->song.sampleLen) return 0;
-  return parent->song.sample[12*sampleBank+(address>>16)]->adpcmRendData[(address&0xffff)];*/
+  switch (type) {
+    case ymfm::ACCESS_ADPCM_A:
+      return parent->adpcmAMem[address&0xffffff];
+    case ymfm::ACCESS_ADPCM_B:
+      return parent->adpcmBMem[address&0xffffff];
+    default:
+      return 0;
+  }
+  return 0;
 }
 
 void DivYM2610Interface::ymfm_external_write(ymfm::access_class type, uint32_t address, uint8_t data) {
-}
\ No newline at end of file
+}
diff --git a/src/engine/sample.cpp b/src/engine/sample.cpp
index ec0ffad5c..ec6313fff 100644
--- a/src/engine/sample.cpp
+++ b/src/engine/sample.cpp
@@ -73,6 +73,7 @@ bool DivSample::save(const char* path) {
   return true;
 }
 
+// 16-bit memory is padded to 512, to make things easier for ADPCM-A/B.
 bool DivSample::initInternal(unsigned char d, int count) {
   switch (d) {
     case 0: // 1-bit
@@ -96,14 +97,14 @@ bool DivSample::initInternal(unsigned char d, int count) {
     case 5: // ADPCM-A
       if (dataA!=NULL) delete[] dataA;
       lengthA=(count+1)/2;
-      dataA=new unsigned char[lengthA];
-      memset(dataA,0,lengthA);
+      dataA=new unsigned char[(lengthA+255)&(~0xff)];
+      memset(dataA,0,(lengthA+255)&(~0xff));
       break;
     case 6: // ADPCM-B
       if (dataB!=NULL) delete[] dataB;
       lengthB=(count+1)/2;
-      dataB=new unsigned char[lengthB];
-      memset(dataB,0,lengthB);
+      dataB=new unsigned char[(lengthB+255)&(~0xff)];
+      memset(dataB,0,(lengthB+255)&(~0xff));
       break;
     case 7: // X68000 ADPCM
       if (dataX68!=NULL) delete[] dataX68;
@@ -132,8 +133,8 @@ bool DivSample::initInternal(unsigned char d, int count) {
     case 16: // 16-bit
       if (data16!=NULL) delete[] data16;
       length16=count*2;
-      data16=new short[count];
-      memset(data16,0,count*sizeof(short));
+      data16=new short[(count+511)&(~0x1ff)];
+      memset(data16,0,((count+511)&(~0x1ff))*sizeof(short));
       break;
     default:
       return false;
@@ -223,13 +224,14 @@ void DivSample::render() {
     if (!initInternal(4,samples)) return;
     bs_encode(data16,dataQSoundA,samples);
   }
+  // TODO: pad to 256.
   if (depth!=5) { // ADPCM-A
     if (!initInternal(5,samples)) return;
-    yma_encode(data16,dataA,samples);
+    yma_encode(data16,dataA,(samples+511)&(~0x1ff));
   }
   if (depth!=6) { // ADPCM-B
     if (!initInternal(6,samples)) return;
-    ymb_encode(data16,dataB,samples);
+    ymb_encode(data16,dataB,(samples+511)&(~0x1ff));
   }
   if (depth!=7) { // X68000 ADPCM
     if (!initInternal(7,samples)) return;
diff --git a/src/engine/vgmOps.cpp b/src/engine/vgmOps.cpp
index 93a2bcf42..e51217dc4 100644
--- a/src/engine/vgmOps.cpp
+++ b/src/engine/vgmOps.cpp
@@ -928,14 +928,14 @@ SafeWriter* DivEngine::saveVGM(bool* sysToExport, bool loop) {
     delete[] pcmMem;
   }
 
-  if (writeADPCM && adpcmMemLen>0) {
+  if (writeADPCM && adpcmAMemLen>0) {
     w->writeC(0x67);
     w->writeC(0x66);
     w->writeC(0x82);
-    w->writeI(adpcmMemLen+8);
-    w->writeI(adpcmMemLen);
+    w->writeI(adpcmAMemLen+8);
+    w->writeI(adpcmAMemLen);
     w->writeI(0);
-    w->write(adpcmMem,adpcmMemLen);
+    w->write(adpcmAMem,adpcmAMemLen);
   }
 
   if (writeQSound && qsoundMemLen>0) {
diff --git a/src/gui/gui.cpp b/src/gui/gui.cpp
index ee8d5a954..bc15e5e5f 100644
--- a/src/gui/gui.cpp
+++ b/src/gui/gui.cpp
@@ -1898,12 +1898,12 @@ void FurnaceGUI::drawStats() {
   }
   if (!statsOpen) return;
   if (ImGui::Begin("Statistics",&statsOpen)) {
-    String adpcmUsage=fmt::sprintf("%d/16384KB",e->adpcmMemLen/1024);
+    String adpcmAUsage=fmt::sprintf("%d/16384KB",e->adpcmAMemLen/1024);
     String adpcmBUsage=fmt::sprintf("%d/16384KB",e->adpcmBMemLen/1024);
     String qsoundUsage=fmt::sprintf("%d/16384KB",e->qsoundMemLen/1024);
     ImGui::Text("ADPCM-A");
     ImGui::SameLine();
-    ImGui::ProgressBar(((float)e->adpcmMemLen)/16777216.0f,ImVec2(-FLT_MIN,0),adpcmUsage.c_str());
+    ImGui::ProgressBar(((float)e->adpcmAMemLen)/16777216.0f,ImVec2(-FLT_MIN,0),adpcmAUsage.c_str());
     ImGui::Text("ADPCM-B");
     ImGui::SameLine();
     ImGui::ProgressBar(((float)e->adpcmBMemLen)/16777216.0f,ImVec2(-FLT_MIN,0),adpcmBUsage.c_str());

From e4ad569f8d097d8afef9f1bb47e8d6ea9e724250 Mon Sep 17 00:00:00 2001
From: tildearrow <tildearrow@protonmail.com>
Date: Thu, 24 Feb 2022 16:53:20 -0500
Subject: [PATCH 2/5] Lynx: fix stereo

---
 src/engine/platform/lynx.cpp | 35 +++++++++++++++++++++--------------
 src/engine/platform/lynx.h   |  4 +++-
 2 files changed, 24 insertions(+), 15 deletions(-)

diff --git a/src/engine/platform/lynx.cpp b/src/engine/platform/lynx.cpp
index eee2b2e22..856950f95 100644
--- a/src/engine/platform/lynx.cpp
+++ b/src/engine/platform/lynx.cpp
@@ -30,6 +30,7 @@
 #define WRITE_CONTROL(ch,v) rWrite(0x25+(ch<<3),(v))
 #define WRITE_OTHER(ch,v) rWrite(0x27+(ch<<3),(v))
 #define WRITE_ATTEN(ch,v) rWrite((0x40+ch),(v))
+#define WRITE_STEREO(v) rWrite(0x50,(v))
 
 #define CHIP_DIVIDER 64
 
@@ -88,9 +89,9 @@ const char* regCheatSheetLynx[]={
 
 const char** DivPlatformLynx::getRegisterSheet() {
   return regCheatSheetLynx;
-}
-
-const char* DivPlatformLynx::getEffectName(unsigned char effect) {
+}
+
+const char* DivPlatformLynx::getEffectName(unsigned char effect) {
   switch (effect)
   {
   case 0x30: case 0x31: case 0x32: case 0x33:
@@ -197,7 +198,8 @@ int DivPlatformLynx::dispatch(DivCommand c) {
       }
       break;
     case DIV_CMD_PANNING:
-      WRITE_ATTEN(c.chan, c.value);
+      chan[c.chan].pan=((c.value&0x0f)<<4)|((c.value&0xf0)>>4);
+      WRITE_ATTEN(c.chan,chan[c.chan].pan);
       break;
     case DIV_CMD_GET_VOLUME:
       if (chan[c.chan].std.hasVol) {
@@ -261,6 +263,10 @@ void DivPlatformLynx::muteChannel(int ch, bool mute) {
   if (chan[ch].active) WRITE_VOLUME(ch,(isMuted[ch]?0:(chan[ch].outVol&127)));
 }
 
+bool DivPlatformLynx::isStereo() {
+  return true;
+}
+
 void DivPlatformLynx::forceIns() {
   for (int i=0; i<4; i++) {
     if (chan[i].active) {
@@ -272,16 +278,16 @@ void DivPlatformLynx::forceIns() {
 
 void* DivPlatformLynx::getChanState(int ch) {
   return &chan[ch];
-}
-
-unsigned char* DivPlatformLynx::getRegisterPool()
-{
-  return const_cast<unsigned char*>( mikey->getRegisterPool() );
-}
-
-int DivPlatformLynx::getRegisterPoolSize()
-{
-  return 4*8+4;
+}
+
+unsigned char* DivPlatformLynx::getRegisterPool()
+{
+  return const_cast<unsigned char*>( mikey->getRegisterPool() );
+}
+
+int DivPlatformLynx::getRegisterPoolSize()
+{
+  return 4*8+4;
 }
 
 void DivPlatformLynx::reset() {
@@ -294,6 +300,7 @@ void DivPlatformLynx::reset() {
   if (dumpWrites) {
     addWrite(0xffffffff,0);
   }
+  WRITE_STEREO(0);
 }
 
 bool DivPlatformLynx::keyOffAffectsArp(int ch) {
diff --git a/src/engine/platform/lynx.h b/src/engine/platform/lynx.h
index 8ad2bf2ce..536a874a8 100644
--- a/src/engine/platform/lynx.h
+++ b/src/engine/platform/lynx.h
@@ -45,7 +45,7 @@ class DivPlatformLynx: public DivDispatch {
     MikeyFreqDiv fd;
     MikeyDuty duty;
     int baseFreq, pitch, note, actualNote, lfsr;
-    unsigned char ins;
+    unsigned char ins, pan;
     bool active, insChanged, freqChanged, keyOn, keyOff, inPorta;
     signed char vol, outVol;
     Channel():
@@ -58,6 +58,7 @@ class DivPlatformLynx: public DivDispatch {
       actualNote(0),
       lfsr(-1),
       ins(-1),
+      pan(0xff),
       active(false),
       insChanged(true),
       freqChanged(false),
@@ -81,6 +82,7 @@ class DivPlatformLynx: public DivDispatch {
     void forceIns();
     void tick();
     void muteChannel(int ch, bool mute);
+    bool isStereo();
     bool keyOffAffectsArp(int ch);
     bool keyOffAffectsPorta(int ch);
     //int getPortaFloor(int ch);

From 82c8b97d9c3e50dfa3f0299c3e6e6b4044258b6f Mon Sep 17 00:00:00 2001
From: tildearrow <tildearrow@protonmail.com>
Date: Thu, 24 Feb 2022 16:53:38 -0500
Subject: [PATCH 3/5] Neo Geo: safety checks

---
 src/engine/engine.h                     | 10 +++++++++-
 src/engine/platform/ym2610Interface.cpp |  4 ++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/src/engine/engine.h b/src/engine/engine.h
index c02416996..be04d1cbb 100644
--- a/src/engine/engine.h
+++ b/src/engine/engine.h
@@ -627,6 +627,10 @@ class DivEngine {
     size_t adpcmBMemLen;
     unsigned char* qsoundMem;
     size_t qsoundMemLen;
+    unsigned char* qsoundAMem;
+    size_t qsoundAMemLen;
+    unsigned char* dpcmMem;
+    size_t dpcmMemLen;
 
     DivEngine():
       output(NULL),
@@ -685,6 +689,10 @@ class DivEngine {
       adpcmBMem(NULL),
       adpcmBMemLen(0),
       qsoundMem(NULL),
-      qsoundMemLen(0) {}
+      qsoundMemLen(0),
+      qsoundAMem(NULL),
+      qsoundAMemLen(0),
+      dpcmMem(NULL),
+      dpcmMemLen(0) {}
 };
 #endif
diff --git a/src/engine/platform/ym2610Interface.cpp b/src/engine/platform/ym2610Interface.cpp
index 45fb5288b..9154b40e7 100644
--- a/src/engine/platform/ym2610Interface.cpp
+++ b/src/engine/platform/ym2610Interface.cpp
@@ -24,8 +24,12 @@
 uint8_t DivYM2610Interface::ymfm_external_read(ymfm::access_class type, uint32_t address) {
   switch (type) {
     case ymfm::ACCESS_ADPCM_A:
+      if (parent->adpcmAMem==NULL) return 0;
+      if ((address&0xffffff)>=parent->adpcmAMemLen) return 0;
       return parent->adpcmAMem[address&0xffffff];
     case ymfm::ACCESS_ADPCM_B:
+      if (parent->adpcmBMem==NULL) return 0;
+      if ((address&0xffffff)>=parent->adpcmBMemLen) return 0;
       return parent->adpcmBMem[address&0xffffff];
     default:
       return 0;

From 4b6d9adcb9b064753c4a30f7f9b894501099e8a0 Mon Sep 17 00:00:00 2001
From: tildearrow <tildearrow@protonmail.com>
Date: Thu, 24 Feb 2022 17:56:19 -0500
Subject: [PATCH 4/5] volume changes

as of now the master volume is 1.0x (it was 2.0x before)
NES has also been amplified.
these changes should not affect older songs.
---
 papers/format.md            |  4 ++++
 src/engine/engine.h         |  4 ++--
 src/engine/fileOps.cpp      | 15 ++++++++++++++-
 src/engine/platform/nes.cpp |  5 ++++-
 src/engine/playback.cpp     | 12 ++++++------
 src/engine/song.h           |  2 ++
 src/gui/gui.cpp             |  4 ++++
 7 files changed, 36 insertions(+), 10 deletions(-)

diff --git a/papers/format.md b/papers/format.md
index a61bb6266..1f44f9ac6 100644
--- a/papers/format.md
+++ b/papers/format.md
@@ -25,6 +25,8 @@ furthermore, an `or reserved` indicates this field is always present, but is res
 
 the format versions are:
 
+- 59: Furnace dev59
+- 58: Furnace dev58
 - 57: Furnace dev57
 
 - 53: Furnace 0.5.7
@@ -201,6 +203,8 @@ size | description
  S?? | channel short names
      | - same as above
  STR | song comment
+  4f | master volume, 1.0f=100% (>=59)
+     | this is 2.0f for modules before 59
 
 # instrument
 
diff --git a/src/engine/engine.h b/src/engine/engine.h
index be04d1cbb..f4324fb6c 100644
--- a/src/engine/engine.h
+++ b/src/engine/engine.h
@@ -37,8 +37,8 @@
     warnings+=(String("\n")+x); \
   }
 
-#define DIV_VERSION "dev58"
-#define DIV_ENGINE_VERSION 58
+#define DIV_VERSION "dev59"
+#define DIV_ENGINE_VERSION 59
 
 enum DivStatusView {
   DIV_STATUS_NOTHING=0,
diff --git a/src/engine/fileOps.cpp b/src/engine/fileOps.cpp
index dd3ff37e2..b8c57c5b3 100644
--- a/src/engine/fileOps.cpp
+++ b/src/engine/fileOps.cpp
@@ -841,7 +841,12 @@ bool DivEngine::loadFur(unsigned char* file, size_t len) {
     if (tchans>DIV_MAX_CHANS) tchans=DIV_MAX_CHANS;
 
     // system volume
-    for (int i=0; i<32; i++) ds.systemVol[i]=reader.readC();
+    for (int i=0; i<32; i++) {
+      ds.systemVol[i]=reader.readC();
+      if (ds.version<59 && ds.system[i]==DIV_SYSTEM_NES) {
+        ds.systemVol[i]/=4;
+      }
+    }
 
     // system panning
     for (int i=0; i<32; i++) ds.systemPan[i]=reader.readC();
@@ -999,6 +1004,12 @@ bool DivEngine::loadFur(unsigned char* file, size_t len) {
       ds.notes=reader.readString();
     }
 
+    if (ds.version>=59) {
+      ds.masterVol=reader.readF();
+    } else {
+      ds.masterVol=2.0f;
+    }
+
     // read instruments
     for (int i=0; i<ds.insLen; i++) {
       DivInstrument* ins=new DivInstrument;
@@ -1444,6 +1455,8 @@ SafeWriter* DivEngine::saveFur() {
 
   w->writeString(song.notes,false);
 
+  w->writeF(song.masterVol);
+
   /// INSTRUMENT
   for (int i=0; i<song.insLen; i++) {
     DivInstrument* ins=song.ins[i];
diff --git a/src/engine/platform/nes.cpp b/src/engine/platform/nes.cpp
index aacadd866..10bb38fec 100644
--- a/src/engine/platform/nes.cpp
+++ b/src/engine/platform/nes.cpp
@@ -99,7 +99,10 @@ void DivPlatformNES::acquire(short* bufL, short* bufR, size_t start, size_t len)
     if (nes->apu.clocked) {
       nes->apu.clocked=false;
     }
-    bufL[i]=(pulse_output(nes)+tnd_output(nes))*30;
+    int sample=(pulse_output(nes)+tnd_output(nes)-128)<<7;
+    if (sample>32767) sample=32767;
+    if (sample<-32768) sample=-32768;
+    bufL[i]=sample;
   }
 }
 
diff --git a/src/engine/playback.cpp b/src/engine/playback.cpp
index 6c825cb71..5fb0c4e86 100644
--- a/src/engine/playback.cpp
+++ b/src/engine/playback.cpp
@@ -1294,17 +1294,17 @@ void DivEngine::nextBuf(float** in, float** out, int inChans, int outChans, unsi
   }
 
   for (int i=0; i<song.systemLen; i++) {
-    float volL=((float)song.systemVol[i]/64.0f)*((float)MIN(127,127-(int)song.systemPan[i])/127.0f);
-    float volR=((float)song.systemVol[i]/64.0f)*((float)MIN(127,127+(int)song.systemPan[i])/127.0f);
+    float volL=((float)song.systemVol[i]/64.0f)*((float)MIN(127,127-(int)song.systemPan[i])/127.0f)*song.masterVol;
+    float volR=((float)song.systemVol[i]/64.0f)*((float)MIN(127,127+(int)song.systemPan[i])/127.0f)*song.masterVol;
     if (disCont[i].dispatch->isStereo()) {
       for (size_t j=0; j<size; j++) {
-        out[0][j]+=((float)disCont[i].bbOut[0][j]/16384.0)*volL;
-        out[1][j]+=((float)disCont[i].bbOut[1][j]/16384.0)*volR;
+        out[0][j]+=((float)disCont[i].bbOut[0][j]/32768.0)*volL;
+        out[1][j]+=((float)disCont[i].bbOut[1][j]/32768.0)*volR;
       }
     } else {
       for (size_t j=0; j<size; j++) {
-        out[0][j]+=((float)disCont[i].bbOut[0][j]/16384.0)*volL;
-        out[1][j]+=((float)disCont[i].bbOut[0][j]/16384.0)*volR;
+        out[0][j]+=((float)disCont[i].bbOut[0][j]/32768.0)*volL;
+        out[1][j]+=((float)disCont[i].bbOut[0][j]/32768.0)*volR;
       }
     }
   }
diff --git a/src/engine/song.h b/src/engine/song.h
index f4620eef9..c80bb6ca8 100644
--- a/src/engine/song.h
+++ b/src/engine/song.h
@@ -241,6 +241,7 @@ struct DivSong {
   bool pal;
   bool customTempo;
   int hz, patLen, ordersLen, insLen, waveLen, sampleLen;
+  float masterVol;
   float tuning;
 
   // compatibility flags
@@ -308,6 +309,7 @@ struct DivSong {
     insLen(0),
     waveLen(0),
     sampleLen(0),
+    masterVol(1.0f),
     tuning(440.0f),
     limitSlides(false),
     linearPitch(true),
diff --git a/src/gui/gui.cpp b/src/gui/gui.cpp
index bc15e5e5f..10a7159c2 100644
--- a/src/gui/gui.cpp
+++ b/src/gui/gui.cpp
@@ -1345,6 +1345,10 @@ void FurnaceGUI::drawMixer() {
   ImGui::SetNextWindowSizeConstraints(ImVec2(400.0f*dpiScale,200.0f*dpiScale),ImVec2(scrW*dpiScale,scrH*dpiScale));
   if (ImGui::Begin("Mixer",&mixerOpen,settings.allowEditDocking?0:ImGuiWindowFlags_NoDocking)) {
     char id[32];
+    if (ImGui::SliderFloat("Master Volume",&e->song.masterVol,0,3,"%.2fx")) {
+      if (e->song.masterVol<0) e->song.masterVol=0;
+      if (e->song.masterVol>3) e->song.masterVol=3;
+    }
     for (int i=0; i<e->song.systemLen; i++) {
       snprintf(id,31,"MixS%d",i);
       bool doInvert=e->song.systemVol[i]&128;

From 28254d4b243235f180c95facc7402af4358c7972 Mon Sep 17 00:00:00 2001
From: tildearrow <tildearrow@protonmail.com>
Date: Thu, 24 Feb 2022 18:00:19 -0500
Subject: [PATCH 5/5] SMS: add 1.79MHz option

---
 src/engine/platform/sms.cpp | 4 +++-
 src/gui/gui.cpp             | 4 ++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/engine/platform/sms.cpp b/src/engine/platform/sms.cpp
index 325665003..114d67b05 100644
--- a/src/engine/platform/sms.cpp
+++ b/src/engine/platform/sms.cpp
@@ -301,7 +301,9 @@ void DivPlatformSMS::poke(std::vector<DivRegWrite>& wlist) {
 }
 
 void DivPlatformSMS::setFlags(unsigned int flags) {
-  if ((flags&3)==2) {
+  if ((flags&3)==3) {
+    chipClock=COLOR_NTSC/2.0;
+  } else if ((flags&3)==2) {
     chipClock=4000000;
   } else if ((flags&3)==1) {
     chipClock=COLOR_PAL*4.0/5.0;
diff --git a/src/gui/gui.cpp b/src/gui/gui.cpp
index 10a7159c2..1a5a13f47 100644
--- a/src/gui/gui.cpp
+++ b/src/gui/gui.cpp
@@ -4544,6 +4544,10 @@ bool FurnaceGUI::loop() {
                   e->setSysFlags(i,(flags&(~3))|2,restart);
                   updateWindowTitle();
                 }
+                if (ImGui::RadioButton("Half NTSC (1.79MHz)",(flags&3)==3)) {
+                  e->setSysFlags(i,(flags&(~3))|3,restart);
+                  updateWindowTitle();
+                }
                 ImGui::Text("Chip type:");
                 if (ImGui::RadioButton("Sega VDP/Master System",((flags>>2)&3)==0)) {
                   e->setSysFlags(i,(flags&(~12))|0,restart);