From d3edc58cb123436cd971a547aeab4a64c9fa3db7 Mon Sep 17 00:00:00 2001
From: tildearrow <tildearrow@protonmail.com>
Date: Mon, 23 May 2022 03:13:22 -0500
Subject: [PATCH] MSM6295: add clock rate flag

---
 src/engine/platform/msm6295.cpp           | 24 ++++++++++++++++++++---
 src/engine/platform/msm6295.h             |  4 +++-
 src/engine/platform/sound/oki/msm6295.cpp | 11 ++++++++---
 src/gui/sysConf.cpp                       | 16 +++++++++++++++
 4 files changed, 48 insertions(+), 7 deletions(-)

diff --git a/src/engine/platform/msm6295.cpp b/src/engine/platform/msm6295.cpp
index 414792313..64ec6b0aa 100644
--- a/src/engine/platform/msm6295.cpp
+++ b/src/engine/platform/msm6295.cpp
@@ -44,7 +44,7 @@ void DivPlatformMSM6295::acquire(short* bufL, short* bufR, size_t start, size_t
         QueuedWrite& w=writes.front();
         msm->command_w(w.val);
         writes.pop();
-        delay=64;
+        delay=32;
       }
     } else {
       delay--;
@@ -53,6 +53,11 @@ void DivPlatformMSM6295::acquire(short* bufL, short* bufR, size_t start, size_t
     msm->tick();
   
     bufL[h]=msm->out()<<4;
+
+    if (++updateOsc>=64) {
+      updateOsc=0;
+      // TODO: per-channel osc
+    }
   }
 }
 
@@ -295,6 +300,19 @@ void DivPlatformMSM6295::renderSamples() {
   }
 }
 
+void DivPlatformMSM6295::setFlags(unsigned int flags) {
+  if (flags&1) {
+    chipClock=8448000;
+  } else {
+    chipClock=8000000;
+  }
+  rate=chipClock/((flags&2)?6:24);
+  for (int i=0; i<4; i++) {
+    isMuted[i]=false;
+    oscBuf[i]->rate=rate/22;
+  }
+}
+
 int DivPlatformMSM6295::init(DivEngine* p, int channels, int sugRate, unsigned int flags) {
   parent=p;
   adpcmMem=new unsigned char[getSampleMemCapacity(0)];
@@ -303,13 +321,13 @@ int DivPlatformMSM6295::init(DivEngine* p, int channels, int sugRate, unsigned i
   iface.sampleBank=0;
   dumpWrites=false;
   skipRegisterWrites=false;
+  updateOsc=0;
   for (int i=0; i<4; i++) {
     isMuted[i]=false;
     oscBuf[i]=new DivDispatchOscBuffer;
   }
-  chipClock=8000000;
-  rate=chipClock/8;
   msm=new msm6295_core(iface);
+  setFlags(flags);
   reset();
   return 4;
 }
diff --git a/src/engine/platform/msm6295.h b/src/engine/platform/msm6295.h
index 4f6cd4ce1..bedaab41c 100644
--- a/src/engine/platform/msm6295.h
+++ b/src/engine/platform/msm6295.h
@@ -98,7 +98,7 @@ class DivPlatformMSM6295: public DivDispatch {
     DivMSM6295Interface iface;
     unsigned char sampleBank;
 
-    int delay;
+    int delay, updateOsc;
 
     bool extMode;
   
@@ -123,12 +123,14 @@ class DivPlatformMSM6295: public DivDispatch {
     void notifyInsDeletion(void* ins);
     void poke(unsigned int addr, unsigned short val);
     void poke(std::vector<DivRegWrite>& wlist);
+    void setFlags(unsigned int flags);
     const char** getRegisterSheet();
     const char* getEffectName(unsigned char effect);
     const void* getSampleMem(int index);
     size_t getSampleMemCapacity(int index);
     size_t getSampleMemUsage(int index);
     void renderSamples();
+    
     int init(DivEngine* parent, int channels, int sugRate, unsigned int flags);
     void quit();
     ~DivPlatformMSM6295();
diff --git a/src/engine/platform/sound/oki/msm6295.cpp b/src/engine/platform/sound/oki/msm6295.cpp
index 29ca31f9d..6d7b860ce 100644
--- a/src/engine/platform/sound/oki/msm6295.cpp
+++ b/src/engine/platform/sound/oki/msm6295.cpp
@@ -53,6 +53,11 @@
 
 #include "msm6295.hpp"
 
+#define CORE_DIVIDER 3
+
+#define CHANNEL_DELAY (15/CORE_DIVIDER)
+#define MASTER_DELAY (33/CORE_DIVIDER)
+
 void msm6295_core::tick()
 {
 	// command handler
@@ -60,7 +65,7 @@ void msm6295_core::tick()
 	{
 		if (bitfield(m_command, 7)) // play voice
 		{
-			if ((++m_clock) >= ((15 * (m_ss ? 5 : 4))))
+			if ((++m_clock) >= ((CHANNEL_DELAY * (m_ss ? 5 : 4))))
 			{
 				m_clock = 0;
 				if (bitfield(m_next_command, 4, 4) != 0)
@@ -84,7 +89,7 @@ void msm6295_core::tick()
 		}
 		else if (bitfield(m_next_command, 7)) // select phrase
 		{
-			if ((++m_clock) >= ((15 * (m_ss ? 5 : 4))))
+			if ((++m_clock) >= ((CHANNEL_DELAY * (m_ss ? 5 : 4))))
 			{
 				m_clock = 0;
 				m_command = m_next_command;
@@ -154,7 +159,7 @@ void msm6295_core::voice_t::tick()
 	else
 	{
 		// playback
-		if ((++m_clock) >= ((33 * (m_host.m_ss ? 5 : 4))))
+		if ((++m_clock) >= ((MASTER_DELAY * (m_host.m_ss ? 5 : 4))))
 		{
 			m_clock = 0;
 			bool is_end = (m_command != 0);
diff --git a/src/gui/sysConf.cpp b/src/gui/sysConf.cpp
index 392d3e3a6..a49db16b3 100644
--- a/src/gui/sysConf.cpp
+++ b/src/gui/sysConf.cpp
@@ -413,6 +413,22 @@ void FurnaceGUI::drawSysConf(int chan, DivSystem type, unsigned int& flags, bool
       }
       break;
     }
+    case DIV_SYSTEM_MSM6295: {
+      ImGui::Text("Clock rate:");
+      if (ImGui::RadioButton("1MHz",flags==0)) {
+        copyOfFlags=0;
+      }
+      if (ImGui::RadioButton("1.056MHz",flags==1)) {
+        copyOfFlags=1;
+      }
+      if (ImGui::RadioButton("4MHz",flags==2)) {
+        copyOfFlags=2;
+      }
+      if (ImGui::RadioButton("4.224MHz",flags==3)) {
+        copyOfFlags=3;
+      }
+      break;
+    }
     case DIV_SYSTEM_GB:
     case DIV_SYSTEM_SWAN:
     case DIV_SYSTEM_VERA: