From 37dbc52a68b234ddd4d594961f48e56e9a90523f Mon Sep 17 00:00:00 2001
From: tildearrow <tildearrow@protonmail.com>
Date: Fri, 23 Dec 2022 19:26:42 -0500
Subject: [PATCH] YM2612: CSM without DualPCM

---
 src/engine/dispatchContainer.cpp   | 6 ++++++
 src/engine/platform/genesis.cpp    | 4 ++--
 src/engine/platform/genesisext.cpp | 4 ++++
 src/engine/platform/genesisext.h   | 1 +
 src/gui/guiConst.cpp               | 2 ++
 5 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/src/engine/dispatchContainer.cpp b/src/engine/dispatchContainer.cpp
index 668864ae..0017ea23 100644
--- a/src/engine/dispatchContainer.cpp
+++ b/src/engine/dispatchContainer.cpp
@@ -201,6 +201,12 @@ void DivDispatchContainer::init(DivSystem sys, DivEngine* eng, int chanCount, do
       ((DivPlatformGenesisExt*)dispatch)->setYMFM(eng->getConfInt("ym2612Core",0));
       ((DivPlatformGenesisExt*)dispatch)->setSoftPCM(false);
       break;
+    case DIV_SYSTEM_YM2612_CSM:
+      dispatch=new DivPlatformGenesisExt;
+      ((DivPlatformGenesisExt*)dispatch)->setYMFM(eng->getConfInt("ym2612Core",0));
+      ((DivPlatformGenesisExt*)dispatch)->setSoftPCM(false);
+      ((DivPlatformGenesisExt*)dispatch)->setCSMChannel(6);
+      break;
     case DIV_SYSTEM_YM2612_DUALPCM:
       dispatch=new DivPlatformGenesis;
       ((DivPlatformGenesis*)dispatch)->setYMFM(eng->getConfInt("ym2612Core",0));
diff --git a/src/engine/platform/genesis.cpp b/src/engine/platform/genesis.cpp
index c6a5abc7..76294524 100644
--- a/src/engine/platform/genesis.cpp
+++ b/src/engine/platform/genesis.cpp
@@ -479,7 +479,7 @@ void DivPlatformGenesis::tick(bool sysTick) {
     }
   }
 
-  for (int i=0; i<7; i++) {
+  for (int i=0; i<csmChan; i++) {
     if (i==2 && extMode) continue;
     if (chan[i].freqChanged) {
       if (parent->song.linearPitch==2) {
@@ -1217,7 +1217,7 @@ void DivPlatformGenesis::poke(std::vector<DivRegWrite>& wlist) {
 }
 
 int DivPlatformGenesis::getPortaFloor(int ch) {
-  return (ch>5)?12:0;
+  return 0;
 }
 
 void DivPlatformGenesis::setYMFM(bool use) {
diff --git a/src/engine/platform/genesisext.cpp b/src/engine/platform/genesisext.cpp
index 20268de9..ae6ac70b 100644
--- a/src/engine/platform/genesisext.cpp
+++ b/src/engine/platform/genesisext.cpp
@@ -746,6 +746,10 @@ int DivPlatformGenesisExt::getPortaFloor(int ch) {
   return (ch>8)?12:0;
 }
 
+void DivPlatformGenesisExt::setCSMChannel(unsigned char ch) {
+  csmChan=ch;
+}
+
 int DivPlatformGenesisExt::init(DivEngine* parent, int channels, int sugRate, const DivConfig& flags) {
   DivPlatformGenesis::init(parent,channels,sugRate,flags);
   for (int i=0; i<4; i++) {
diff --git a/src/engine/platform/genesisext.h b/src/engine/platform/genesisext.h
index eec093a8..304f609f 100644
--- a/src/engine/platform/genesisext.h
+++ b/src/engine/platform/genesisext.h
@@ -42,6 +42,7 @@ class DivPlatformGenesisExt: public DivPlatformGenesis {
     bool keyOffAffectsPorta(int ch);
     void notifyInsChange(int ins);
     int getPortaFloor(int ch);
+    void setCSMChannel(unsigned char ch);
     int init(DivEngine* parent, int channels, int sugRate, const DivConfig& flags);
     void quit();
     ~DivPlatformGenesisExt();
diff --git a/src/gui/guiConst.cpp b/src/gui/guiConst.cpp
index cb6b24dc..0c8a6d02 100644
--- a/src/gui/guiConst.cpp
+++ b/src/gui/guiConst.cpp
@@ -913,6 +913,7 @@ const FurnaceGUIColorDef guiColors[GUI_COLOR_MAX]={
 const int availableSystems[]={
   DIV_SYSTEM_YM2612,
   DIV_SYSTEM_YM2612_EXT,
+  DIV_SYSTEM_YM2612_CSM,
   DIV_SYSTEM_YM2612_DUALPCM,
   DIV_SYSTEM_YM2612_DUALPCM_EXT,
   DIV_SYSTEM_SMS,
@@ -994,6 +995,7 @@ const int availableSystems[]={
 const int chipsFM[]={
   DIV_SYSTEM_YM2612,
   DIV_SYSTEM_YM2612_EXT,
+  DIV_SYSTEM_YM2612_CSM,
   DIV_SYSTEM_YM2612_DUALPCM,
   DIV_SYSTEM_YM2612_DUALPCM_EXT,
   DIV_SYSTEM_YM2151,