From 26739bba1167d875d9479a178ebed09ae702332d Mon Sep 17 00:00:00 2001
From: tildearrow <tildearrow@protonmail.com>
Date: Sun, 5 Feb 2023 17:42:48 -0500
Subject: [PATCH] YM2612: fix CSM on ymfm

finally
---
 src/engine/platform/genesis.cpp            | 19 ++++++++++++++-----
 src/engine/platform/genesis.h              |  5 +++--
 src/engine/platform/sound/ymfm/ymfm_fm.ipp |  6 ++++++
 3 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/src/engine/platform/genesis.cpp b/src/engine/platform/genesis.cpp
index 239ad5f7c..05d3c08be 100644
--- a/src/engine/platform/genesis.cpp
+++ b/src/engine/platform/genesis.cpp
@@ -30,17 +30,26 @@
 
 void DivYM2612Interface::ymfm_set_timer(uint32_t tnum, int32_t duration_in_clocks) {
   if (tnum==1) {
-    countB=duration_in_clocks;
+    setB=duration_in_clocks;
   } else if (tnum==0) {
-    countA=duration_in_clocks;
+    setA=duration_in_clocks;
   }
-  //logV("ymfm_set_timer(%d,%d)",tnum,duration_in_clocks);
 }
 
 void DivYM2612Interface::clock() {
-  if (countA>=0) {
+  if (setA>=0) {
     countA-=144;
-    if (countA<0) m_engine->engine_timer_expired(0);
+    if (countA<0) {
+      m_engine->engine_timer_expired(0);
+      countA+=setA;
+    }
+  }
+  if (setB>=0) {
+    countB-=144;
+    if (countB<0) {
+      m_engine->engine_timer_expired(1);
+      countB+=setB;
+    }
   }
 }
 
diff --git a/src/engine/platform/genesis.h b/src/engine/platform/genesis.h
index 37449eb91..87b37e841 100644
--- a/src/engine/platform/genesis.h
+++ b/src/engine/platform/genesis.h
@@ -25,6 +25,7 @@
 
 
 class DivYM2612Interface: public ymfm::ymfm_interface {
+  int setA, setB;
   int countA, countB;
 
   public:
@@ -32,8 +33,8 @@ class DivYM2612Interface: public ymfm::ymfm_interface {
     void ymfm_set_timer(uint32_t tnum, int32_t duration_in_clocks);
     DivYM2612Interface():
       ymfm::ymfm_interface(),
-      countA(-1),
-      countB(-1) {}
+      countA(0),
+      countB(0) {}
 };
 
 class DivPlatformGenesis: public DivPlatformOPN {
diff --git a/src/engine/platform/sound/ymfm/ymfm_fm.ipp b/src/engine/platform/sound/ymfm/ymfm_fm.ipp
index 4fdff8a38..81b351fe9 100644
--- a/src/engine/platform/sound/ymfm/ymfm_fm.ipp
+++ b/src/engine/platform/sound/ymfm/ymfm_fm.ipp
@@ -431,6 +431,12 @@ bool fm_operator<RegisterType>::prepare()
 
 	// clock the key state
 	clock_keystate(uint32_t(m_keyon_live != 0));
+        if (m_keyon_live & (1<<KEYON_CSM)) {
+          if (!(m_keyon_live & (1<<KEYON_NORMAL))) {
+            clock_keystate(0);
+          } else {
+          }
+        }
 	m_keyon_live &= ~(1 << KEYON_CSM);
 
 	// we're active until we're quiet after the release