Add AY-3-8914 support as configurable in AY-3-8910

Previous PR (https://github.com/tildearrow/furnace/pull/278) is closed due this, but archived for info.
It's AY with 4 level envelope volume per channel and different register format.

papers/doc/7-systems/ay8910.md

@@ -4,6 +4,8 @@ this chip was used in several home computers (ZX Spectrum, MSX, Amstrad CPC, Ata
 
 the chip's powerful sound comes from the envelope...
 
+AY-3-8914 variant was used in Intellivision, it's basically original AY with 4 level envelope volume per channel and different register format.
+
 # effects
 
 - `20xx`: set channel mode. `xx` may be one of the following:

src/engine/platform/ay.cpp

@@ -24,7 +24,7 @@
 #include <math.h>
 
 #define rWrite(a,v) if (!skipRegisterWrites) {pendingWrites[a]=v;}
-#define immWrite(a,v) if (!skipRegisterWrites) {writes.emplace(a,v); if (dumpWrites) {addWrite(a,v);} }
+#define immWrite(a,v) if (!skipRegisterWrites) {writes.emplace(regRemap(a),v); if (dumpWrites) {addWrite(regRemap(a),v);} }
 
 #define CHIP_DIVIDER 8
 
@@ -48,8 +48,28 @@ const char* regCheatSheetAY[]={
   NULL
 };
 
+const char* regCheatSheetAY8914[]={
+  "FreqL_A", "0",
+  "FreqL_B", "1",
+  "FreqL_C", "2",
+  "FreqL_Env", "3",
+  "FreqH_A", "4",
+  "FreqH_B", "5",
+  "FreqH_C", "6",
+  "FreqH_Env", "7",
+  "Enable", "8",
+  "FreqNoise", "9",
+  "Control_Env", "A",
+  "Volume_A", "B",
+  "Volume_B", "C",
+  "Volume_C", "D",
+  "PortA", "E",
+  "PortB", "F",
+  NULL
+};
+
 const char** DivPlatformAY8910::getRegisterSheet() {
-  return regCheatSheetAY;
+  return intellivision?regCheatSheetAY8914:regCheatSheetAY;
 }
 
 const char* DivPlatformAY8910::getEffectName(unsigned char effect) {
@@ -92,8 +112,13 @@ void DivPlatformAY8910::acquire(short* bufL, short* bufR, size_t start, size_t l
   }
   while (!writes.empty()) {
     QueuedWrite w=writes.front();
-    ay->address_w(w.addr);
+    if (intellivision) {
-    ay->data_w(w.val);
+      ay8914_device* ay8914=(ay8914_device*)ay;
+      ay8914->write(w.addr,w.val);
+    } else {
+      ay->address_w(w.addr);
+      ay->data_w(w.val);
+    }
     regPool[w.addr&0x0f]=w.val;
     writes.pop();
   }
@@ -125,6 +150,8 @@ void DivPlatformAY8910::tick() {
       if (chan[i].outVol<0) chan[i].outVol=0;
       if (isMuted[i]) {
         rWrite(0x08+i,0);
+      } else if (intellivision && (chan[i].psgMode&4)) {
+        rWrite(0x08+i,(chan[i].outVol&0xc)<<2);
       } else {
         rWrite(0x08+i,(chan[i].outVol&15)|((chan[i].psgMode&4)<<2));
       }
@@ -151,6 +178,8 @@ void DivPlatformAY8910::tick() {
       chan[i].psgMode=(chan[i].std.wave+1)&7;
       if (isMuted[i]) {
         rWrite(0x08+i,0);
+      } else if (intellivision && (chan[i].psgMode&4)) {
+        rWrite(0x08+i,(chan[i].outVol&0xc)<<2);
       } else {
         rWrite(0x08+i,(chan[i].outVol&15)|((chan[i].psgMode&4)<<2));
       }
@@ -242,6 +271,8 @@ int DivPlatformAY8910::dispatch(DivCommand c) {
       chan[c.chan].std.init(ins);
       if (isMuted[c.chan]) {
         rWrite(0x08+c.chan,0);
+      } else if (intellivision && (chan[c.chan].psgMode&4)) {
+        rWrite(0x08+c.chan,(chan[c.chan].vol&0xc)<<2);
       } else {
         rWrite(0x08+c.chan,(chan[c.chan].vol&15)|((chan[c.chan].psgMode&4)<<2));
       }
@@ -264,7 +295,13 @@ int DivPlatformAY8910::dispatch(DivCommand c) {
       if (isMuted[c.chan]) {
         rWrite(0x08+c.chan,0);
       } else {
-        if (chan[c.chan].active) rWrite(0x08+c.chan,(chan[c.chan].vol&15)|((chan[c.chan].psgMode&4)<<2));
+        if (chan[c.chan].active) {
+          if (intellivision && (chan[c.chan].psgMode&4)) {
+            rWrite(0x08+c.chan,(chan[c.chan].vol&0xc)<<2);
+          } else {
+            rWrite(0x08+c.chan,(chan[c.chan].vol&15)|((chan[c.chan].psgMode&4)<<2));
+          }
+        }
       }
       break;
     }
@@ -317,7 +354,11 @@ int DivPlatformAY8910::dispatch(DivCommand c) {
         if (isMuted[c.chan]) {
           rWrite(0x08+c.chan,0);
         } else if (chan[c.chan].active) {
-          rWrite(0x08+c.chan,(chan[c.chan].outVol&15)|((chan[c.chan].psgMode&4)<<2));
+          if (intellivision && (chan[c.chan].psgMode&4)) {
+            rWrite(0x08+c.chan,(chan[c.chan].outVol&0xc)<<2);
+          } else {
+            rWrite(0x08+c.chan,(chan[c.chan].outVol&15)|((chan[c.chan].psgMode&4)<<2));
+          }
         }
       }
       break;
@@ -334,6 +375,8 @@ int DivPlatformAY8910::dispatch(DivCommand c) {
       }
       if (isMuted[c.chan]) {
         rWrite(0x08+c.chan,0);
+      } else if (intellivision && (chan[c.chan].psgMode&4)) {
+        rWrite(0x08+c.chan,(chan[c.chan].vol&0xc)<<2);
       } else {
         rWrite(0x08+c.chan,(chan[c.chan].vol&15)|((chan[c.chan].psgMode&4)<<2));
       }
@@ -383,6 +426,8 @@ void DivPlatformAY8910::muteChannel(int ch, bool mute) {
   isMuted[ch]=mute;
   if (isMuted[ch]) {
     rWrite(0x08+ch,0);
+  } else if (intellivision && (chan[ch].psgMode&4)) {
+    rWrite(0x08+ch,(chan[ch].vol&0xc)<<2);
   } else {
     rWrite(0x08+ch,(chan[ch].outVol&15)|((chan[ch].psgMode&4)<<2));
   }
@@ -508,14 +553,22 @@ void DivPlatformAY8910::setFlags(unsigned int flags) {
     case 1:
       ay=new ym2149_device(rate);
       sunsoft=false;
+      intellivision=false;
       break;
     case 2:
       ay=new sunsoft_5b_sound_device(rate);
       sunsoft=true;
+      intellivision=false;
+      break;
+    case 3:
+      ay=new ay8914_device(rate);
+      sunsoft=false;
+      intellivision=true;
       break;
     default:
       ay=new ay8910_device(rate);
       sunsoft=false;
+      intellivision=false;
       break;
   }
   ay->device_start();

src/engine/platform/ay.h

@@ -26,6 +26,10 @@
 
 class DivPlatformAY8910: public DivDispatch {
   protected:
+    const unsigned char AY8914RegRemap[16]={
+      0,4,1,5,2,6,9,8,11,12,13,3,7,10,14,15
+    };
+    inline unsigned char regRemap(unsigned char reg) { return intellivision?AY8914RegRemap[reg&0x0f]:reg&0x0f; }
     struct Channel {
       unsigned char freqH, freqL;
       int freq, baseFreq, note, pitch;
@@ -60,7 +64,7 @@ class DivPlatformAY8910: public DivDispatch {
     int delay;
 
     bool extMode;
-    bool stereo, sunsoft;
+    bool stereo, sunsoft, intellivision;
   
     short oldWrites[16];
     short pendingWrites[16];

src/engine/sysDef.cpp

@@ -419,10 +419,6 @@ const char* DivEngine::getSongSystemName() {
             return "Vectrex";
           case 5: // AY-3-8910, 1MHz
             return "Amstrad CPC";
-          case 6: // AY-3-8910, 0.somethingMhz
-            return "Intellivision";
-          case 8: // AY-3-8910, 0.somethingMhz
-            return "Intellivision (PAL)";
 
           case 0x10: // YM2149, 1.79MHz
             return "MSX";
@@ -432,7 +428,12 @@ const char* DivEngine::getSongSystemName() {
             return "Sunsoft 5B standalone";
           case 0x28: // 5B PAL
             return "Sunsoft 5B standalone (PAL)";
-          
+
+          case 0x30: // AY-3-8914, 1.79MHz
+            return "Intellivision";
+          case 0x33: // AY-3-8914, 2MHz
+            return "Intellivision (PAL)";
+
           default:
             if ((song.systemFlags[0]&0x30)==0x00) {
               return "AY-3-8910";
@@ -440,6 +441,8 @@ const char* DivEngine::getSongSystemName() {
               return "Yamaha YM2149";
             } else if ((song.systemFlags[0]&0x30)==0x20) {
               return "Overclocked Sunsoft 5B";
+            } else if ((song.systemFlags[0]&0x30)==0x30) {
+              return "Intellivision";
             }
         }
       } else if (song.system[0]==DIV_SYSTEM_SMS) {

src/gui/gui.cpp

@@ -5116,6 +5116,10 @@ bool FurnaceGUI::loop() {
                     e->setSysFlags(i,(flags&(~0x30))|32,restart);
                     updateWindowTitle();
                   }
+                  if (ImGui::RadioButton("AY-3-8914",(flags&0x30)==48)) {
+                    e->setSysFlags(i,(flags&(~0x30))|48,restart);
+                    updateWindowTitle();
+                  }
                 }
                 bool stereo=flags&0x40;
                 ImGui::BeginDisabled((flags&0x30)==32);
@@ -6684,7 +6688,7 @@ FurnaceGUI::FurnaceGUI():
   ));
   cat.systems.push_back(FurnaceGUISysDef(
     "Mattel Intellivision", {
-      DIV_SYSTEM_AY8910, 64, 0, 6,
+      DIV_SYSTEM_AY8910, 64, 0, 48,
       0
     }
   ));