Merge pull request #825 from tildearrow/ymf289b

Prepare to YMF289B OPL3-L support

extern/opl/MODIFIED.md

@@ -1,4 +1,4 @@
 # modification disclaimer
 
-this is a modified version of Nuked-OPL3 which implements channel muting in the core.
+this is a modified version of Nuked-OPL3 which implements channel muting in the core, and resampling function.
 see [this issue](https://github.com/tildearrow/furnace/issues/414) for more information.

extern/opl/opl3.c

@@ -1362,6 +1362,11 @@ void OPL3_Reset(opl3_chip *chip, uint32_t samplerate)
 #endif
 }
 
+void OPL3_Resample(opl3_chip *chip, uint32_t samplerate)
+{
+    chip->rateratio = (samplerate << RSM_FRAC) / 49716;
+}
+
 void OPL3_WriteReg(opl3_chip *chip, uint16_t reg, uint8_t v)
 {
     uint8_t high = (reg >> 8) & 0x01;

extern/opl/opl3.h

@@ -158,6 +158,7 @@ struct _opl3_chip {
 void OPL3_Generate(opl3_chip *chip, int16_t *buf);
 void OPL3_GenerateResampled(opl3_chip *chip, int16_t *buf);
 void OPL3_Reset(opl3_chip *chip, uint32_t samplerate);
+void OPL3_Resample(opl3_chip *chip, uint32_t samplerate);
 void OPL3_WriteReg(opl3_chip *chip, uint16_t reg, uint8_t v);
 void OPL3_WriteRegBuffered(opl3_chip *chip, uint16_t reg, uint8_t v);
 void OPL3_GenerateStream(opl3_chip *chip, int16_t *sndptr, uint32_t numsamples);

src/engine/platform/opl.cpp

@@ -275,11 +275,20 @@ void DivPlatformOPL::acquire_nuked(short** buf, size_t len) {
     if (os[3]>32767) os[3]=32767;
   
     buf[0][h]=os[0];
-    if (oplType==3 || oplType==759) {
+    if (totalOutputs>1) {
       buf[1][h]=os[1];
+    }
+    if (totalOutputs>2) {
       buf[2][h]=os[2];
+    }
+    if (totalOutputs>3) {
       buf[3][h]=os[3];
     }
+    if (totalOutputs==6) {
+      // placeholder for OPL4
+      buf[4][h]=0;
+      buf[5][h]=0;
+    }
   }
 }
 
@@ -1590,7 +1599,7 @@ void DivPlatformOPL::reset() {
   }
   */
   if (downsample) {
-    const unsigned int downsampledRate=(unsigned int)((double)rate*rate/chipRateBase);
+    const unsigned int downsampledRate=(unsigned int)((double)rate*round(COLOR_NTSC/72.0)/(double)chipRateBase);
     OPL3_Reset(&fm,downsampledRate);
   } else {
     OPL3_Reset(&fm,rate);
@@ -1671,7 +1680,7 @@ void DivPlatformOPL::reset() {
 }
 
 int DivPlatformOPL::getOutputCount() {
-  return (oplType==3 || oplType==759)?4:1;
+  return totalOutputs;
 }
 
 bool DivPlatformOPL::keyOffAffectsArp(int ch) {
@@ -1730,6 +1739,7 @@ void DivPlatformOPL::setOPLType(int type, bool drums) {
       if (type==8950) {
         adpcmChan=drums?11:9;
       }
+      totalOutputs=1;
       break;
     case 3: case 4: case 759:
       slotsNonDrums=slotsOPL3;
@@ -1748,6 +1758,7 @@ void DivPlatformOPL::setOPLType(int type, bool drums) {
         chipFreqBase=32768*684;
         downsample=true;
       }
+      totalOutputs=(type==4)?6:4;
       break;
   }
   chipType=type;
@@ -1829,14 +1840,36 @@ void DivPlatformOPL::setFlags(const DivConfig& flags) {
         case 0x04:
           chipClock=15000000.0;
           break;
+        case 0x05:
+          chipClock=33868800.0;
+          break;
         default:
           chipClock=COLOR_NTSC*4.0;
           break;
       }
       CHECK_CUSTOM_CLOCK;
-      rate=chipClock/288;
+      switch (flags.getInt("chipType",0)) {
-      chipRateBase=rate;
+        case 1: // YMF289B
-      compatPan=flags.getBool("compatPan",false);
+          chipFreqBase=32768*684;
+          rate=chipClock/768;
+          chipRateBase=chipClock/684;
+          downsample=true;
+          totalOutputs=2; // Stereo output only
+          break;
+        default: // YMF262
+          chipFreqBase=32768*288;
+          rate=chipClock/288;
+          chipRateBase=rate;
+          downsample=false;
+          totalOutputs=4;
+          break;
+      }
+      if (downsample) {
+        const unsigned int downsampledRate=(unsigned int)((double)rate*round(COLOR_NTSC/72.0)/(double)chipRateBase);
+        OPL3_Resample(&fm,downsampledRate);
+      } else {
+        OPL3_Resample(&fm,rate);
+      }
       break;
     case 4:
       switch (flags.getInt("clockSel",0)) {
@@ -1860,6 +1893,7 @@ void DivPlatformOPL::setFlags(const DivConfig& flags) {
       chipClock=rate*288;
       break;
   }
+  compatPan=flags.getBool("compatPan",false);
 
   for (int i=0; i<20; i++) {
     oscBuf[i]->rate=rate;

src/engine/platform/opl.h

@@ -82,7 +82,7 @@ class DivPlatformOPL: public DivDispatch {
     const unsigned short* chanMap;
     const unsigned char* outChanMap;
     int chipFreqBase, chipRateBase;
-    int delay, chipType, oplType, chans, melodicChans, totalChans, adpcmChan, sampleBank;
+    int delay, chipType, oplType, chans, melodicChans, totalChans, adpcmChan, sampleBank, totalOutputs;
     unsigned char lastBusy;
     unsigned char drumState;
     unsigned char drumVol[5];

src/gui/presets.cpp

@@ -2334,6 +2334,22 @@ void FurnaceGUI::initSystemPresets() {
       CH(DIV_SYSTEM_OPL3_DRUMS, 1.0f, 0, "")
     }
   );
+  ENTRY(
+    "Yamaha YMF289B (OPL3-L)", {
+      CH(DIV_SYSTEM_OPL3, 1.0f, 0, 
+         "clockSel=5\n"
+         "chipType=1\n"
+      )
+    }
+  );
+  ENTRY(
+    "Yamaha YMF289B (drums mode)", {
+      CH(DIV_SYSTEM_OPL3_DRUMS, 1.0f, 0, 
+         "clockSel=5\n"
+         "chipType=1\n"
+      )
+    }
+  );
   if (settings.hiddenSystems) {
     ENTRY(
       "Yamaha YMU759 (MA-2)", {

src/gui/sysConf.cpp

@@ -1478,6 +1478,7 @@ bool FurnaceGUI::drawSysConf(int chan, DivSystem type, DivConfig& flags, bool mo
     case DIV_SYSTEM_OPL3:
     case DIV_SYSTEM_OPL3_DRUMS: {
       int clockSel=flags.getInt("clockSel",0);
+      int chipType=flags.getInt("chipType",0);
       bool compatPan=flags.getBool("compatPan",false);
 
       ImGui::Text("Clock rate:");
@@ -1502,6 +1503,19 @@ bool FurnaceGUI::drawSysConf(int chan, DivSystem type, DivConfig& flags, bool mo
         clockSel=4;
         altered=true;
       }
+      if (ImGui::RadioButton("33.8688MHz (OPL3-L)",clockSel==5)) {
+        clockSel=5;
+        altered=true;
+      }
+      ImGui::Text("Chip type:");
+      if (ImGui::RadioButton("OPL3 (YMF262)",chipType==0)) {
+        chipType=0;
+        altered=true;
+      }
+      if (ImGui::RadioButton("OPL3-L (YMF289B)",chipType==1)) {
+        chipType=1;
+        altered=true;
+      }
       ImGui::Unindent();
 
       if (ImGui::Checkbox("Compatible panning (0800)",&compatPan)) {
@@ -1511,6 +1525,7 @@ bool FurnaceGUI::drawSysConf(int chan, DivSystem type, DivConfig& flags, bool mo
       if (altered) {
         e->lockSave([&]() {
           flags.set("clockSel",clockSel);
+          flags.set("chipType",chipType);
           flags.set("compatPan",compatPan);
         });
       }

src/gui/sysPartNumber.cpp

@@ -156,9 +156,15 @@ const char* FurnaceGUI::getSystemPartNumber(DivSystem sys, DivConfig& flags) {
       return "YM3812";
       break;
     case DIV_SYSTEM_OPL3:
-    case DIV_SYSTEM_OPL3_DRUMS:
+    case DIV_SYSTEM_OPL3_DRUMS:{
-      return "YMF262";
+      int chipType=flags.getInt("chipType",0);
+      if (chipType==1) {
+        return "YMF289B";
+      } else {
+        return "YMF262";
+      }
       break;
+    }
     case DIV_SYSTEM_OPL4:
     case DIV_SYSTEM_OPL4_DRUMS:
       return "YMF278";