From f13271750236230d9a1eb1877cd99845673e102d Mon Sep 17 00:00:00 2001
From: tildearrow <tildearrow@protonmail.com>
Date: Wed, 14 Dec 2022 19:09:50 -0500
Subject: [PATCH] YM2612: prepare to implement CSM on ymfm

---
 src/engine/platform/genesis.cpp | 18 ++++++++++++++++++
 src/engine/platform/genesis.h   |  8 ++++++++
 2 files changed, 26 insertions(+)

diff --git a/src/engine/platform/genesis.cpp b/src/engine/platform/genesis.cpp
index adfdf258..1f79cd0d 100644
--- a/src/engine/platform/genesis.cpp
+++ b/src/engine/platform/genesis.cpp
@@ -19,6 +19,7 @@
 
 #include "genesis.h"
 #include "../engine.h"
+#include "../../ta-log.h"
 #include <string.h>
 #include <math.h>
 
@@ -27,6 +28,22 @@
 
 #define IS_REALLY_MUTED(x) (isMuted[x] && (x<5 || !softPCM || (isMuted[5] && isMuted[6])))
 
+void DivYM2612Interface::ymfm_set_timer(uint32_t tnum, int32_t duration_in_clocks) {
+  if (tnum==1) {
+    countB=duration_in_clocks;
+  } else if (tnum==0) {
+    countA=duration_in_clocks;
+  }
+  logV("ymfm_set_timer(%d,%d)",tnum,duration_in_clocks);
+}
+
+void DivYM2612Interface::clock() {
+  if (countA>=0) {
+    countA-=144;
+    if (countA<0) m_engine->engine_timer_expired(0);
+  }
+}
+
 void DivPlatformGenesis::processDAC(int iRate) {
   if (softPCM) {
     softPCMTimer+=chipClock/576;
@@ -192,6 +209,7 @@ void DivPlatformGenesis::acquire_ymfm(short* bufL, short* bufR, size_t start, si
       lastBusy=1;
     }
     
+    iface.clock();
     if (ladder) {
       fm_ymfm->generate(&out_ymfm);
     } else {
diff --git a/src/engine/platform/genesis.h b/src/engine/platform/genesis.h
index ac2e5432..bd5d9aff 100644
--- a/src/engine/platform/genesis.h
+++ b/src/engine/platform/genesis.h
@@ -26,7 +26,15 @@
 
 
 class DivYM2612Interface: public ymfm::ymfm_interface {
+  int countA, countB;
 
+  public:
+    void clock();
+    void ymfm_set_timer(uint32_t tnum, int32_t duration_in_clocks);
+    DivYM2612Interface():
+      ymfm::ymfm_interface(),
+      countA(-1),
+      countB(-1) {}
 };
 
 class DivPlatformGenesis: public DivPlatformOPN {