Prepare to YMF289B OPL3-L support

src/engine/platform/opl.cpp

@@ -1722,13 +1722,29 @@ 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;
-      chipRateBase=rate;
+      switch (flags.getInt("chipType",0)) {
+        case 1: // YMF289B
+          chipFreqBase=32768*684;
+          rate=chipClock/684;
+          chipRateBase=chipClock/768;
+          downsample=true;
+          break;
+        default: // YMF262
+          chipFreqBase=32768*288;
+          rate=chipClock/288;
+          chipRateBase=rate;
+          downsample=false;
+          break;
+      }
+      reset();
       break;
     case 4:
       switch (flags.getInt("clockSel",0)) {

src/gui/presets.cpp

@@ -2248,6 +2248,16 @@ void FurnaceGUI::initSystemPresets() {
       CH(DIV_SYSTEM_OPL3_DRUMS, 64, 0, "")
     }
   );
+  ENTRY(
+    "Yamaha YMF289B (OPL3-L)", {
+      CH(DIV_SYSTEM_OPL3, 64, 0, "chipType=1")
+    }
+  );
+  ENTRY(
+    "Yamaha YMF289B (drums mode)", {
+      CH(DIV_SYSTEM_OPL3_DRUMS, 64, 0, "chipType=1")
+    }
+  );
   if (settings.hiddenSystems) {
     ENTRY(
       "Yamaha YMU759 (MA-2)", {

src/gui/sysConf.cpp

@@ -1182,6 +1182,7 @@ 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);
 
       ImGui::Text("Clock rate:");
       if (ImGui::RadioButton("14.32MHz (NTSC)",clockSel==0)) {
@@ -1204,10 +1205,24 @@ 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;
+      }
 
       if (altered) {
         e->lockSave([&]() {
           flags.set("clockSel",clockSel);
+          flags.set("chipType",chipType);
         });
       }
       break;