From 6fe58a396560490cee6926abd5766b34c6b4fc6d Mon Sep 17 00:00:00 2001
From: tildearrow <tildearrow@protonmail.com>
Date: Sat, 7 May 2022 21:48:29 -0500
Subject: [PATCH] OPL: implement hard reset

fixes #437
---
 src/engine/platform/opl.cpp | 27 +++++++++++++++++++++++++++
 src/engine/platform/opl.h   |  3 ++-
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/src/engine/platform/opl.cpp b/src/engine/platform/opl.cpp
index e43895289..dec39d8be 100644
--- a/src/engine/platform/opl.cpp
+++ b/src/engine/platform/opl.cpp
@@ -445,10 +445,34 @@ void DivPlatformOPL::tick(bool sysTick) {
     }
 
     if (i<melodicChans) {
+      if (chan[i].hardReset && chan[i].keyOn) {
+        for (int j=0; j<ops; j++) {
+          unsigned char slot=slots[j][i];
+          if (slot==255) continue;
+          unsigned short baseAddr=slotMap[slot];
+          DivInstrumentFM::Operator& op=chan[i].state.op[(ops==4)?orderedOpsL[j]:j];
+          immWrite(baseAddr+ADDR_SL_RR,0x0f);
+          immWrite(baseAddr+ADDR_KSL_TL,63|(op.ksl<<6));
+          oldWrites[baseAddr+ADDR_SL_RR]=-1;
+          oldWrites[baseAddr+ADDR_KSL_TL]=-1;
+        }
+      }
       if (chan[i].keyOn || chan[i].keyOff) {
         immWrite(chanMap[i]+ADDR_FREQH,0x00|(chan[i].freqH&31));
         chan[i].keyOff=false;
       }
+      if (chan[i].hardReset && chan[i].keyOn) {
+        for (int j=0; j<ops; j++) {
+          unsigned char slot=slots[j][i];
+          if (slot==255) continue;
+          unsigned short baseAddr=slotMap[slot];
+          DivInstrumentFM::Operator& op=chan[i].state.op[(ops==4)?orderedOpsL[j]:j];
+          for (int k=0; k<5; k++) {
+            immWrite(baseAddr+ADDR_SL_RR,0x0f);
+            immWrite(baseAddr+ADDR_KSL_TL,63|(op.ksl<<6));
+          }
+        }
+      }
     }
   }
 
@@ -1118,6 +1142,9 @@ int DivPlatformOPL::dispatch(DivCommand c) {
       }
       break;
     }
+    case DIV_CMD_FM_HARD_RESET:
+      chan[c.chan].hardReset=c.value;
+      break;
     case DIV_ALWAYS_SET_VOLUME:
       return 0;
       break;
diff --git a/src/engine/platform/opl.h b/src/engine/platform/opl.h
index 0a5cfa52b..64db4d665 100644
--- a/src/engine/platform/opl.h
+++ b/src/engine/platform/opl.h
@@ -31,7 +31,7 @@ class DivPlatformOPL: public DivDispatch {
       DivMacroInt std;
       unsigned char freqH, freqL;
       int freq, baseFreq, pitch, pitch2, note, ins;
-      bool active, insChanged, freqChanged, keyOn, keyOff, portaPause, furnaceDac, inPorta, fourOp;
+      bool active, insChanged, freqChanged, keyOn, keyOff, portaPause, furnaceDac, inPorta, fourOp, hardReset;
       int vol, outVol;
       unsigned char pan;
       void macroInit(DivInstrument* which) {
@@ -56,6 +56,7 @@ class DivPlatformOPL: public DivDispatch {
         furnaceDac(false),
         inPorta(false),
         fourOp(false),
+        hardReset(false),
         vol(0),
         pan(3) {
         state.ops=2;