implement Furnace-style PCM on Arcade/Gen/NES/PCE

src/engine/platform/arcade.cpp

@@ -199,6 +199,16 @@ void DivPlatformArcade::tick() {
       chan[i].keyOn=false;
     }
   }
+
+  for (int i=8; i<13; i++) {
+    if (chan[i].freqChanged) {
+      chan[i].freq=chan[i].baseFreq+(chan[i].pitch>>1)-64;
+      if (chan[i].furnacePCM) {
+        chan[i].pcm.freq=MIN(255,((440.0*pow(2.0,double(chan[i].freq+256)/(64.0*12.0)))*255)/31250);
+      }
+      chan[i].freqChanged=false;
+    }
+  }
 }
 
 void DivPlatformArcade::muteChannel(int ch, bool mute) {
@@ -216,8 +226,20 @@ void DivPlatformArcade::muteChannel(int ch, bool mute) {
 int DivPlatformArcade::dispatch(DivCommand c) {
   switch (c.cmd) {
     case DIV_CMD_NOTE_ON: {
+      DivInstrument* ins=parent->getIns(chan[c.chan].ins);
       if (c.chan>7) {
         if (skipRegisterWrites) break;
+        if (ins->type==DIV_INS_AMIGA) {
+          chan[c.chan].pcm.sample=ins->amiga.initSample;
+          if (chan[c.chan].pcm.sample<0 || chan[c.chan].pcm.sample>=parent->song.sampleLen) {
+            chan[c.chan].pcm.sample=-1;
+            break;
+          }
+          chan[c.chan].pcm.pos=0;
+          chan[c.chan].baseFreq=c.value<<6;
+          chan[c.chan].freqChanged=true;
+          chan[c.chan].furnacePCM=true;
+        } else {
           chan[c.chan].pcm.sample=12*sampleBank+c.value%12;
           if (chan[c.chan].pcm.sample>=parent->song.sampleLen) {
             chan[c.chan].pcm.sample=-1;
@@ -225,9 +247,10 @@ int DivPlatformArcade::dispatch(DivCommand c) {
           }
           chan[c.chan].pcm.pos=0;
           chan[c.chan].pcm.freq=MIN(255,(parent->song.sample[chan[c.chan].pcm.sample]->rate*255)/31250);
+          chan[c.chan].furnacePCM=false;
+        }
         break;
       }
-      DivInstrument* ins=parent->getIns(chan[c.chan].ins);
 
       for (int i=0; i<4; i++) {
         unsigned short baseAddr=chanOffs[c.chan]|opOffs[i];

src/engine/platform/arcade.h

@@ -16,7 +16,7 @@ class DivPlatformArcade: public DivDispatch {
       int freq, baseFreq, pitch;
       unsigned char ins;
       signed char konCycles;
-      bool active, insChanged, freqChanged, keyOn, keyOff, portaPause;
+      bool active, insChanged, freqChanged, keyOn, keyOff, portaPause, furnacePCM;
       int vol;
       unsigned char chVolL, chVolR;
 
@@ -27,7 +27,7 @@ class DivPlatformArcade: public DivDispatch {
         unsigned char freq;
         PCMChannel(): sample(-1), pos(0), len(0), freq(0) {}
       } pcm;
-      Channel(): freqH(0), freqL(0), freq(0), baseFreq(0), pitch(0), ins(-1), active(false), insChanged(true), freqChanged(false), keyOn(false), keyOff(false), portaPause(false), vol(0), chVolL(127), chVolR(127) {}
+      Channel(): freqH(0), freqL(0), freq(0), baseFreq(0), pitch(0), ins(-1), active(false), insChanged(true), freqChanged(false), keyOn(false), keyOff(false), portaPause(false), furnacePCM(false), vol(0), chVolL(127), chVolR(127) {}
     };
     Channel chan[13];
     struct QueuedWrite {

src/engine/platform/genesis.cpp

@@ -32,7 +32,7 @@ void DivPlatformGenesis::acquire(short* bufL, short* bufR, size_t start, size_t
             dacSample=-1;
           }
         }
-        dacPeriod+=dacRate;
+        dacPeriod+=MAX(40,dacRate);
       }
     }
   
@@ -102,6 +102,9 @@ void DivPlatformGenesis::tick() {
       int freqt=toFreq(chan[i].freq);
       immWrite(chanOffs[i]+0xa4,freqt>>8);
       immWrite(chanOffs[i]+0xa0,freqt&0xff);
+      if (chan[i].furnaceDac) {
+        dacRate=(1280000*1.25)/chan[i].baseFreq;
+      }
       chan[i].freqChanged=false;
     }
     if (chan[i].keyOn) {
@@ -171,8 +174,21 @@ int DivPlatformGenesis::dispatch(DivCommand c) {
   }
   switch (c.cmd) {
     case DIV_CMD_NOTE_ON: {
+      DivInstrument* ins=parent->getIns(chan[c.chan].ins);
       if (c.chan==5 && dacMode) {
         if (skipRegisterWrites) break;
+        if (ins->type==DIV_INS_AMIGA) { // Furnace mode
+          dacSample=ins->amiga.initSample;
+          if (dacSample<0 || dacSample>=parent->song.sampleLen) {
+            dacSample=-1;
+            break;
+          }
+          dacPos=0;
+          dacPeriod=0;
+          chan[c.chan].baseFreq=644.0f*pow(2.0f,((float)c.value/12.0f));
+          chan[c.chan].freqChanged=true;
+          chan[c.chan].furnaceDac=true;
+        } else { // compatible mode
           dacSample=12*sampleBank+c.value%12;
           if (dacSample>=parent->song.sampleLen) {
             dacSample=-1;
@@ -181,10 +197,10 @@ int DivPlatformGenesis::dispatch(DivCommand c) {
           dacPos=0;
           dacPeriod=0;
           dacRate=1280000/parent->song.sample[dacSample]->rate;
+          chan[c.chan].furnaceDac=false;
+        }
         break;
       }      
-      DivInstrument* ins=parent->getIns(chan[c.chan].ins);
-      
       
       for (int i=0; i<4; i++) {
         unsigned short baseAddr=chanOffs[c.chan]|opOffs[i];

src/engine/platform/genesis.h

@@ -13,10 +13,10 @@ class DivPlatformGenesis: public DivDispatch {
       int freq, baseFreq, pitch;
       unsigned char ins;
       signed char konCycles;
-      bool active, insChanged, freqChanged, keyOn, keyOff, portaPause;
+      bool active, insChanged, freqChanged, keyOn, keyOff, portaPause, furnaceDac;
       int vol;
       unsigned char pan;
-      Channel(): freqH(0), freqL(0), freq(0), baseFreq(0), pitch(0), ins(-1), active(false), insChanged(true), freqChanged(false), keyOn(false), keyOff(false), portaPause(false), vol(0), pan(3) {}
+      Channel(): freqH(0), freqL(0), freq(0), baseFreq(0), pitch(0), ins(-1), active(false), insChanged(true), freqChanged(false), keyOn(false), keyOff(false), portaPause(false), furnaceDac(false), vol(0), pan(3) {}
     };
     Channel chan[10];
     bool isMuted[10];

src/engine/platform/nes.cpp

@@ -158,12 +158,39 @@ void DivPlatformNES::tick() {
       chan[i].freqChanged=false;
     }
   }
+
+  // PCM
+  if (chan[4].freqChanged) {
+    chan[4].freq=parent->calcFreq(chan[4].baseFreq,chan[4].pitch,false);
+    if (chan[4].furnaceDac) {
+      dacRate=MIN(chan[4].freq,32000);
+    }
+    chan[4].freqChanged=false;
+  }
 }
 
 int DivPlatformNES::dispatch(DivCommand c) {
   switch (c.cmd) {
     case DIV_CMD_NOTE_ON:
       if (c.chan==4) { // PCM
+        DivInstrument* ins=parent->getIns(chan[c.chan].ins);
+        if (ins->type==DIV_INS_AMIGA) {
+          dacSample=ins->amiga.initSample;
+          if (dacSample<0 || dacSample>=parent->song.sampleLen) {
+            dacSample=-1;
+            break;
+          }
+          dacPos=0;
+          dacPeriod=0;
+          chan[c.chan].baseFreq=440.0f*pow(2.0f,((float)(c.value+3)/12.0f));
+          if (c.value!=DIV_NOTE_NULL) {
+            chan[c.chan].freqChanged=true;
+            chan[c.chan].note=c.value;
+          }
+          chan[c.chan].active=true;
+          chan[c.chan].keyOn=true;
+          chan[c.chan].furnaceDac=true;
+        } else {
           dacSample=12*sampleBank+c.value%12;
           if (dacSample>=parent->song.sampleLen) {
             dacSample=-1;
@@ -172,6 +199,8 @@ int DivPlatformNES::dispatch(DivCommand c) {
           dacPos=0;
           dacPeriod=0;
           dacRate=parent->song.sample[dacSample]->rate;
+          chan[c.chan].furnaceDac=false;
+        }
         break;
       } else if (c.chan==3) { // noise
         if (c.value!=DIV_NOTE_NULL) {

src/engine/platform/nes.h

@@ -8,7 +8,7 @@ class DivPlatformNES: public DivDispatch {
   struct Channel {
     int freq, baseFreq, pitch, prevFreq;
     unsigned char ins, note, duty, sweep;
-    bool active, insChanged, freqChanged, sweepChanged, keyOn, keyOff, inPorta;
+    bool active, insChanged, freqChanged, sweepChanged, keyOn, keyOff, inPorta, furnaceDac;
     signed char vol, outVol, wave;
     DivMacroInt std;
     Channel():
@@ -27,6 +27,7 @@ class DivPlatformNES: public DivDispatch {
       keyOn(false),
       keyOff(false),
       inPorta(false),
+      furnaceDac(false),
       vol(15),
       outVol(15),
       wave(-1) {}

src/engine/platform/pce.cpp

@@ -127,6 +127,9 @@ void DivPlatformPCE::tick() {
     if (chan[i].freqChanged || chan[i].keyOn || chan[i].keyOff) {
       //DivInstrument* ins=parent->getIns(chan[i].ins);
       chan[i].freq=parent->calcFreq(chan[i].baseFreq,chan[i].pitch,true);
+      if (chan[i].furnaceDac) {
+        chan[i].dacRate=chan[i].freq;
+      }
       if (chan[i].freq>4095) chan[i].freq=4095;
       if (chan[i].note>0x5d) chan[i].freq=0x01;
       chWrite(i,0x02,chan[i].freq&0xff);
@@ -153,6 +156,24 @@ int DivPlatformPCE::dispatch(DivCommand c) {
   switch (c.cmd) {
     case DIV_CMD_NOTE_ON:
       if (chan[c.chan].pcm) {
+        DivInstrument* ins=parent->getIns(chan[c.chan].ins);
+        if (ins->type==DIV_INS_AMIGA) {
+          chan[c.chan].dacSample=ins->amiga.initSample;
+          if (chan[c.chan].dacSample<0 || chan[c.chan].dacSample>=parent->song.sampleLen) {
+            chan[c.chan].dacSample=-1;
+            break;
+          }
+          chan[c.chan].dacPos=0;
+          chan[c.chan].dacPeriod=0;
+          if (c.value!=DIV_NOTE_NULL) {
+            chan[c.chan].baseFreq=round(FREQ_BASE/pow(2.0f,((float)c.value/12.0f)));
+            chan[c.chan].freqChanged=true;
+            chan[c.chan].note=c.value;
+          }
+          chan[c.chan].active=true;
+          chan[c.chan].keyOn=true;
+          chan[c.chan].furnaceDac=true;
+        } else {
           chan[c.chan].dacSample=12*sampleBank+c.value%12;
           if (chan[c.chan].dacSample>=parent->song.sampleLen) {
             chan[c.chan].dacSample=-1;
@@ -161,6 +182,8 @@ int DivPlatformPCE::dispatch(DivCommand c) {
           chan[c.chan].dacPos=0;
           chan[c.chan].dacPeriod=0;
           chan[c.chan].dacRate=1789773/parent->song.sample[chan[c.chan].dacSample]->rate;
+          chan[c.chan].furnaceDac=false;
+        }
         break;
       }
       if (c.value!=DIV_NOTE_NULL) {

src/engine/platform/pce.h

@@ -13,7 +13,7 @@ class DivPlatformPCE: public DivDispatch {
     unsigned int dacPos;
     int dacSample;
     unsigned char ins, pan;
-    bool active, insChanged, freqChanged, keyOn, keyOff, inPorta, noise, pcm;
+    bool active, insChanged, freqChanged, keyOn, keyOff, inPorta, noise, pcm, furnaceDac;
     signed char vol, outVol, wave;
     DivMacroInt std;
     Channel():
@@ -24,7 +24,7 @@ class DivPlatformPCE: public DivDispatch {
       dacPeriod(0),
       dacRate(0),
       dacPos(0),
-      dacSample(0),
+      dacSample(-1),
       ins(-1),
       pan(255),
       active(false),
@@ -35,6 +35,7 @@ class DivPlatformPCE: public DivDispatch {
       inPorta(false),
       noise(false),
       pcm(false),
+      furnaceDac(false),
       vol(31),
       outVol(31),
       wave(-1) {}