From 93deeecadfb3694c4c7059a2585ab8d32516fab3 Mon Sep 17 00:00:00 2001
From: stephena <stephena@8b62c5a3-ac7e-4cc8-8f21-d9a121418aba>
Date: Thu, 24 May 2012 21:41:54 +0000
Subject: [PATCH] More work on Chetiry bankswitch scheme.  I may not get it
 finished before the release tomorrow (since I'm not entirely sure how it
 works), but I'm going to give it the old college try.

git-svn-id: svn://svn.code.sf.net/p/stella/code/trunk@2497 8b62c5a3-ac7e-4cc8-8f21-d9a121418aba
---
 src/emucore/CartCTY.cxx      | 99 ++++++++++++++++++++++++++++++------
 src/emucore/CartCTY.hxx      | 31 +++++++++--
 src/emucore/CartCTYTunes.hxx | 21 ++++++++
 3 files changed, 133 insertions(+), 18 deletions(-)

diff --git a/src/emucore/CartCTY.cxx b/src/emucore/CartCTY.cxx
index 2d2b22f9e..7f8321c97 100644
--- a/src/emucore/CartCTY.cxx
+++ b/src/emucore/CartCTY.cxx
@@ -31,8 +31,12 @@ CartridgeCTY::CartridgeCTY(const uInt8* image, uInt32 size, const OSystem& osyst
   : Cartridge(osystem.settings()),
     myOSystem(osystem),
     myOperationType(0),
+    myCounter(0),
     myLDAimmediate(false),
-    myRamAccessTimeout(0)
+    myRandomNumber(0x2B435044),
+    myRamAccessTimeout(0),
+    mySystemCycles(0),
+    myFractionalClocks(0.0)
 {
   // Copy the ROM image into my buffer
   memcpy(myImage, image, BSPF_min(32768u, size));
@@ -41,6 +45,9 @@ CartridgeCTY::CartridgeCTY(const uInt8* image, uInt32 size, const OSystem& osyst
   // This cart contains 64 bytes extended RAM @ 0x1000
   registerRamArea(0x1000, 64, 0x40, 0x00);
 
+  // Point to the first tune
+  myFrequencyImage = CartCTYTunes;
+
   // Remember startup bank (not bank 0, since that's ARM code)
   myStartBank = 1;
 }
@@ -62,10 +69,21 @@ void CartridgeCTY::reset()
 
   myRAM[0] = myRAM[1] = myRAM[2] = myRAM[3] = 0xFF;
 
+  // Update cycles to the current system cycles
+  mySystemCycles = mySystem->cycles();
+  myFractionalClocks = 0.0;
+
   // Upon reset we switch to the startup bank
   bank(myStartBank);
 }
 
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+void CartridgeCTY::systemCyclesReset()
+{
+  // Adjust the cycle counter so that it reflects the new value
+  mySystemCycles -= mySystem->cycles();
+}
+
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 void CartridgeCTY::install(System& system)
 {
@@ -101,6 +119,18 @@ uInt8 CartridgeCTY::peek(uInt16 address)
   if(myLDAimmediate && peekValue == 0xF2)
   {
     myLDAimmediate = false;
+
+    // Update the music data fetchers (counter & flag)
+    updateMusicModeDataFetchers();
+
+#if 0
+    // using myDisplayImage[] instead of myProgramImage[] because waveforms
+    // can be modified during runtime.
+    uInt32 i = myDisplayImage[(myMusicWaveforms[0] << 5) + (myMusicCounters[0] >> 27)] +
+               myDisplayImage[(myMusicWaveforms[1] << 5) + (myMusicCounters[1] >> 27)] +
+               myDisplayImage[(myMusicWaveforms[2] << 5) + (myMusicCounters[2] >> 27)];
+    return = (uInt8)i;
+#endif
     return 0xF2;  // FIXME - return frequency value here
   }
   else
@@ -122,19 +152,18 @@ uInt8 CartridgeCTY::peek(uInt16 address)
   else if(address < 0x0080)  // Read port is at $1040 - $107F (64 bytes)
   {
     address -= 0x40;
-    switch(address)  // FIXME for actual return values (0-3)
+    switch(address)
     {
       case 0x00:  // Error code after operation
         return myRAM[0];
       case 0x01:  // Get next Random Number (8-bit LFSR)
-        cerr << "Get next Random Number (8-bit LFSR)\n";
-        return 0xFF;
+        myRandomNumber = ((myRandomNumber & (1<<10)) ? 0x10adab1e: 0x00) ^
+                         ((myRandomNumber >> 11) | (myRandomNumber << 21));
+        return myRandomNumber & 0xFF;
       case 0x02:  // Get Tune position (low byte)
-        cerr << "Get Tune position (low byte)\n";
-        return 0x00;
+        return myCounter & 0xFF;
       case 0x03:  // Get Tune position (high byte)
-        cerr << "Get Tune position (high byte)\n";
-        return 0x00;
+        return (myCounter >> 8) & 0xFF;
       default:
         return myRAM[address];
     }
@@ -180,14 +209,14 @@ bool CartridgeCTY::poke(uInt16 address, uInt8 value)
       case 0x00:  // Operation type for $1FF4
         myOperationType = value;
         break;
-      case 0x01:  // Set Random seed value
-        cerr << "Set random seed value = " << HEX2 << (int)value << endl;
+      case 0x01:  // Set Random seed value (reset)
+        myRandomNumber = 0x2B435044;
         break;
       case 0x02:  // Reset fetcher to beginning of tune
-        cerr << "Reset fetcher to beginning of tune\n";
+        myCounter = 0;
         break;
       case 0x03:  // Advance fetcher to next tune position
-        cerr << "Advance fetcher to next tune position\n";
+        myCounter = (myCounter + 3) & 0x0fff;
         break;
       default:
         myRAM[address] = value;
@@ -282,8 +311,15 @@ bool CartridgeCTY::save(Serializer& out) const
   {
     out.putString(name());
     out.putShort(bank());
-    out.putByte(myOperationType);
     out.putByteArray(myRAM, 64);
+
+    out.putByte(myOperationType);
+    out.putShort(myCounter);
+    out.putBool(myLDAimmediate);
+    out.putInt(myRandomNumber);
+    out.putInt(mySystemCycles);
+    out.putInt((uInt32)(myFractionalClocks * 100000000.0));
+
   }
   catch(const char* msg)
   {
@@ -304,9 +340,14 @@ bool CartridgeCTY::load(Serializer& in)
 
     // Remember what bank we were in
     bank(in.getShort());
+    in.getByteArray(myRAM, 64);
 
     myOperationType = in.getByte();
-    in.getByteArray(myRAM, 64);
+    myCounter = in.getShort();
+    myLDAimmediate = in.getBool();
+    myRandomNumber = in.getInt();
+    mySystemCycles = (Int32)in.getInt();
+    myFractionalClocks = (double)in.getInt() / 100000000.0;
   }
   catch(const char* msg)
   {
@@ -405,7 +446,13 @@ uInt8 CartridgeCTY::ramReadWrite()
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 void CartridgeCTY::loadTune(uInt8 index)
 {
-  cerr << "load tune " << (int)index << endl;
+  // Each tune is offset by 4096 bytes
+  // Instead of copying non-modifiable data around (as would happen on the
+  // Harmony), we simply point to the appropriate tune
+  myFrequencyImage = CartCTYTunes + (index << 12);
+
+  // Reset to beginning of tune
+  myCounter = 0;
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@@ -482,3 +529,25 @@ void CartridgeCTY::wipeAllScores()
     }
   }
 }
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+inline void CartridgeCTY::updateMusicModeDataFetchers()
+{
+  // Calculate the number of cycles since the last update
+  Int32 cycles = mySystem->cycles() - mySystemCycles;
+  mySystemCycles = mySystem->cycles();
+
+  // Calculate the number of DPC OSC clocks since the last update
+  double clocks = ((20000.0 * cycles) / 1193191.66666667) + myFractionalClocks;
+  Int32 wholeClocks = (Int32)clocks;
+  myFractionalClocks = clocks - (double)wholeClocks;
+
+  if(wholeClocks <= 0)
+    return;
+
+  // Let's update counters and flags of the music mode data fetchers
+  for(int x = 0; x <= 2; ++x)
+  {
+//    myMusicCounters[x] += myMusicFrequencies[x];
+  }
+}
diff --git a/src/emucore/CartCTY.hxx b/src/emucore/CartCTY.hxx
index e59768fa2..175cd3047 100644
--- a/src/emucore/CartCTY.hxx
+++ b/src/emucore/CartCTY.hxx
@@ -130,6 +130,13 @@ class CartridgeCTY : public Cartridge
     */
     void reset();
 
+    /**
+      Notification method invoked by the system right before the
+      system resets its cycle counter to zero.  It may be necessary
+      to override this method for devices that remember cycle counts.
+    */
+    void systemCyclesReset();
+
     /**
       Install cartridge in the specified system.  Invoked by the system
       when the cartridge is attached to it.
@@ -238,6 +245,12 @@ class CartridgeCTY : public Cartridge
     void saveScore(uInt8 index);
     void wipeAllScores();
 
+    /** 
+      Updates any data fetchers in music mode based on the number of
+      CPU cycles which have passed since the last update.
+    */
+    void updateMusicModeDataFetchers();
+
   private:
     // OSsytem currently in use
     const OSystem& myOSystem;
@@ -254,13 +267,19 @@ class CartridgeCTY : public Cartridge
     // Operation type (written to $1000, used by hotspot $1FF4)
     uInt8 myOperationType;
 
-    // The 8K Harmony RAM (used for tune data)
-    // Data is accessed from Harmony EEPROM
-    uInt8 myTuneRAM[8192];
+    // Pointer to the 28K frequency table (points to the start of one
+    // of seven 4K tunes in CartCTYTunes)
+    const uInt8* myFrequencyImage;
+
+    // The counter register for the data fetcher
+    uInt16 myCounter;
 
     // Flags that last byte peeked was A9 (LDA #)
     bool myLDAimmediate;
 
+    // The random number generator register
+    uInt32 myRandomNumber;
+
     // The time after which the first request of a load/save operation
     // will actually be completed
     // Due to Harmony EEPROM constraints, a read/write isn't instantaneous,
@@ -270,6 +289,12 @@ class CartridgeCTY : public Cartridge
     // Full pathname of the file to use when emulating load/save
     // of internal RAM to Harmony cart EEPROM
     string myEEPROMFile;
+
+    // System cycle count when the last update to music data fetchers occurred
+    Int32 mySystemCycles;
+
+    // Fractional DPC music OSC clocks unused during the last update
+    double myFractionalClocks;
 };
 
 #endif
diff --git a/src/emucore/CartCTYTunes.hxx b/src/emucore/CartCTYTunes.hxx
index 10b875d55..76ae10b30 100644
--- a/src/emucore/CartCTYTunes.hxx
+++ b/src/emucore/CartCTYTunes.hxx
@@ -28,6 +28,9 @@
 #define CHETIRY_TUNES_SIZE 7 * 4096
 
 static const uInt8 CartCTYTunes[CHETIRY_TUNES_SIZE] = {
+  ///////////////////////////
+  // Tune 1
+  ///////////////////////////
   0x25, 0x20, 0x02, 0x00, 0x00, 0x00, 0x25, 0x20, 0x00, 0x00, 0x00, 0x00, 0x25, 0x20, 0x00, 0x00, 
   0x00, 0x00, 0x25, 0x20, 0x00, 0x00, 0x00, 0x00, 0x23, 0x25, 0x00, 0x00, 0x00, 0x00, 0x22, 0x27, 
   0x00, 0x00, 0x00, 0x00, 0x20, 0x29, 0x00, 0x00, 0x00, 0x00, 0x1e, 0x2a, 0x00, 0x00, 0x00, 0x00, 
@@ -284,6 +287,9 @@ static const uInt8 CartCTYTunes[CHETIRY_TUNES_SIZE] = {
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+  ///////////////////////////
+  // Tune 2
+  ///////////////////////////
   0x2e, 0x29, 0x0a, 0x00, 0x00, 0x00, 0x00, 0x00, 0x16, 0x00, 0x00, 0x00, 0x29, 0x26, 0x0a, 0x00, 
   0x00, 0x00, 0x2a, 0x27, 0x16, 0x00, 0x00, 0x00, 0x2c, 0x29, 0x0a, 0x00, 0x00, 0x00, 0x2e, 0x00, 
   0x16, 0x2c, 0x00, 0x00, 0x2a, 0x27, 0x0a, 0x00, 0x00, 0x00, 0x29, 0x25, 0x16, 0x00, 0x00, 0x00, 
@@ -540,6 +546,9 @@ static const uInt8 CartCTYTunes[CHETIRY_TUNES_SIZE] = {
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+  ///////////////////////////
+  // Tune 3
+  ///////////////////////////
   0x02, 0x16, 0x02, 0x00, 0x02, 0x00, 0x00, 0x16, 0x00, 0x00, 0x16, 0x00, 0x00, 0x11, 0x00, 0x00, 
   0x02, 0x00, 0x00, 0x11, 0x00, 0x00, 0x02, 0x00, 0x00, 0x16, 0x00, 0x00, 0x02, 0x00, 0x00, 0x16, 
   0x00, 0x00, 0x16, 0x00, 0x00, 0x11, 0x00, 0x00, 0x02, 0x00, 0x00, 0x11, 0x00, 0x00, 0x02, 0x00, 
@@ -796,6 +805,9 @@ static const uInt8 CartCTYTunes[CHETIRY_TUNES_SIZE] = {
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+  ///////////////////////////
+  // Tune 4
+  ///////////////////////////
   0x27, 0x02, 0x14, 0x00, 0x00, 0x00, 0x00, 0x00, 0x1b, 0x00, 0x00, 0x00, 0x00, 0x00, 0x17, 0x00, 
   0x00, 0x00, 0x2c, 0x00, 0x1b, 0x00, 0x00, 0x00, 0x2f, 0x02, 0x14, 0x00, 0x00, 0x00, 0x00, 0x00, 
   0x1b, 0x00, 0x00, 0x00, 0x00, 0x00, 0x17, 0x00, 0x00, 0x00, 0x2c, 0x00, 0x1b, 0x00, 0x00, 0x00, 
@@ -1052,6 +1064,9 @@ static const uInt8 CartCTYTunes[CHETIRY_TUNES_SIZE] = {
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+  ///////////////////////////
+  // Tune 5
+  ///////////////////////////
   0x1e, 0x02, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x22, 0x00, 0x00, 0x00, 
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x25, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
   0x00, 0x00, 0x00, 0x00, 0x25, 0x02, 0x12, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
@@ -1308,6 +1323,9 @@ static const uInt8 CartCTYTunes[CHETIRY_TUNES_SIZE] = {
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+  ///////////////////////////
+  // Tune 6
+  ///////////////////////////
   0x29, 0x02, 0x16, 0x00, 0x00, 0x00, 0x29, 0x1d, 0x19, 0x00, 0x00, 0x00, 0x2a, 0x02, 0x11, 0x29, 
   0x00, 0x00, 0x27, 0x1d, 0x19, 0x2a, 0x00, 0x00, 0x29, 0x02, 0x18, 0x00, 0x00, 0x00, 0x27, 0x1e, 
   0x1b, 0x00, 0x00, 0x00, 0x25, 0x02, 0x12, 0x00, 0x00, 0x00, 0x27, 0x1e, 0x0f, 0x00, 0x00, 0x00, 
@@ -1564,6 +1582,9 @@ static const uInt8 CartCTYTunes[CHETIRY_TUNES_SIZE] = {
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
+  ///////////////////////////
+  // Tune 7
+  ///////////////////////////
   0x27, 0x02, 0x02, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 
   0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x25, 0x02, 0x0f, 0x00, 0x00, 0x00, 0x00, 0x00, 
   0x00, 0x00, 0x00, 0x00, 0x22, 0x1b, 0x16, 0x00, 0x00, 0x00, 0x23, 0x00, 0x00, 0x00, 0x00, 0x00,