OPL: pretend to be YMU and enable SOME emulation?

src/engine/dispatchContainer.cpp

@@ -150,6 +150,10 @@ void DivDispatchContainer::init(DivSystem sys, DivEngine* eng, int chanCount, do
   bbInLen=32768;
 
   switch (sys) {
+    case DIV_SYSTEM_YMU759:
+      dispatch=new DivPlatformOPL;
+      ((DivPlatformOPL*)dispatch)->setOPLType(759,false);
+      break;
     case DIV_SYSTEM_YM2612:
       dispatch=new DivPlatformGenesis;
       ((DivPlatformGenesis*)dispatch)->setYMFM(eng->getConfInt("ym2612Core",0));

src/engine/fileOps.cpp

@@ -223,7 +223,7 @@ bool DivEngine::loadDMF(unsigned char* file, size_t len) {
       }
       ds.customTempo=true;
       ds.timeBase=0;
-      addWarning("Yamaha YMU759 emulation is not currently possible!");
+      addWarning("Yamaha YMU759 emulation is incomplete! please migrate your song to the OPL3 system.");
     }
 
     logI("reading pattern matrix (%d)...\n",ds.ordersLen);
@@ -277,6 +277,9 @@ bool DivEngine::loadDMF(unsigned char* file, size_t len) {
       if ((ds.system[0]==DIV_SYSTEM_SMS_OPLL || ds.system[0]==DIV_SYSTEM_NES_VRC7) && ins->type==DIV_INS_FM) {
         ins->type=DIV_INS_OPLL;
       }
+      if (ds.system[0]==DIV_SYSTEM_YMU759) {
+        ins->type=DIV_INS_OPL;
+      }
 
       if (ins->mode) { // FM
         ins->fm.alg=reader.readC();
@@ -573,6 +576,10 @@ bool DivEngine::loadDMF(unsigned char* file, size_t len) {
               pat->data[k][1]-=2;
             }
           }
+          if (ds.system[0]==DIV_SYSTEM_YMU759 && pat->data[k][0]!=0) {
+            // apparently YMU759 is stored 2 octaves lower
+            pat->data[k][1]+=2;
+          }
           if (pat->data[k][0]==0 && pat->data[k][1]!=0) {
             logD("what? %d:%d:%d note %d octave %d\n",i,j,k,pat->data[k][0],pat->data[k][1]);
             pat->data[k][0]=12;

src/engine/platform/opl.cpp

@@ -560,6 +560,11 @@ int DivPlatformOPL::dispatch(DivCommand c) {
       chan[c.chan].std.release();
       break;
     case DIV_CMD_VOLUME: {
+      if (pretendYMU) {
+        c.value=pow(((double)c.value/127.0),0.5)*63.0;
+        if (c.value<0) c.value=0;
+        if (c.value>63) c.value=63;
+      }
       chan[c.chan].vol=c.value;
       if (!chan[c.chan].std.hasVol) {
         chan[c.chan].outVol=c.value;
@@ -716,6 +721,7 @@ int DivPlatformOPL::dispatch(DivCommand c) {
       return 0;
       break;
     case DIV_CMD_GET_VOLMAX:
+      if (pretendYMU) return 127;
       return 63;
       break;
     case DIV_CMD_PRE_PORTA:
@@ -868,6 +874,7 @@ void DivPlatformOPL::setYMFM(bool use) {
 }
 
 void DivPlatformOPL::setOPLType(int type, bool drums) {
+  pretendYMU=false;
   switch (type) {
     case 1: case 2:
       slotsNonDrums=slotsOPL2;
@@ -879,7 +886,7 @@ void DivPlatformOPL::setOPLType(int type, bool drums) {
       melodicChans=drums?6:9;
       totalChans=drums?11:9;
       break;
-    case 3:
+    case 3: case 759:
       slotsNonDrums=slotsOPL3;
       slotsDrums=slotsOPL3Drums;
       slots=drums?slotsDrums:slotsNonDrums;
@@ -888,9 +895,14 @@ void DivPlatformOPL::setOPLType(int type, bool drums) {
       chans=18;
       melodicChans=drums?15:18;
       totalChans=drums?20:18;
+      if (type==759) pretendYMU=true;
       break;
   }
-  oplType=type;
+  if (type==759) {
+    oplType=3;
+  } else {
+    oplType=type;
+  }
   properDrumsSys=drums;
 }
 

src/engine/platform/opl.h

@@ -79,7 +79,7 @@ class DivPlatformOPL: public DivDispatch {
 
     unsigned char lfoValue;
 
-    bool useYMFM, update4OpMask;
+    bool useYMFM, update4OpMask, pretendYMU;
   
     short oldWrites[512];
     short pendingWrites[512];