diff --git a/stella/src/emucore/TIA.cxx b/stella/src/emucore/TIA.cxx
index 501ae2795..ba4555330 100644
--- a/stella/src/emucore/TIA.cxx
+++ b/stella/src/emucore/TIA.cxx
@@ -13,7 +13,7 @@
 // See the file "license" for information on usage and redistribution of
 // this file, and for a DISCLAIMER OF ALL WARRANTIES.
 //
-// $Id: TIA.cxx,v 1.38 2005-02-22 02:59:54 stephena Exp $
+// $Id: TIA.cxx,v 1.39 2005-04-21 18:55:15 stephena Exp $
 //============================================================================
 
 #include <cassert>
@@ -49,6 +49,9 @@ TIA::TIA(const Console& console, Sound& sound, Settings& settings)
   myCurrentFrameBuffer = new uInt8[160 * 300];
   myPreviousFrameBuffer = new uInt8[160 * 300];
 
+  for(uInt32 i = 0; i < 6; ++i)
+    myBitEnabled[i] = true;
+
   for(uInt16 x = 0; x < 2; ++x)
   {
     for(uInt16 enabled = 0; enabled < 256; ++enabled)
@@ -186,7 +189,6 @@ void TIA::reset()
   myPOSM1 = 0;
   myPOSBL = 0;
 
-
   // Some default values for the "current" variables
   myCurrentGRP0 = 0;
   myCurrentGRP1 = 0;
@@ -202,6 +204,9 @@ void TIA::reset()
   myM0CosmicArkMotionEnabled = false;
   myM0CosmicArkCounter = 0;
 
+  for(uInt32 i = 0; i < 6; ++i)
+    myBitEnabled[i] = true;
+
   myDumpEnabled = false;
   myDumpDisabledCycle = 0;
 
@@ -358,6 +363,11 @@ bool TIA::save(Serializer& out)
     out.putBool(myM0CosmicArkMotionEnabled);
     out.putLong(myM0CosmicArkCounter);
 
+    // There are currently six bits defined in TIABit
+    out.putLong(6);
+    for(uInt32 i = 0; i < 6; ++i)
+      out.putBool(myBitEnabled[i]);
+
     out.putBool(myDumpEnabled);
     out.putLong(myDumpDisabledCycle);
 
@@ -454,6 +464,11 @@ bool TIA::load(Deserializer& in)
     myM0CosmicArkMotionEnabled = in.getBool();
     myM0CosmicArkCounter = (uInt32) in.getLong();
 
+    // We abuse the concept of 'enum' here
+    uInt32 limit = (uInt32) in.getLong();
+    for(uInt32 i = 0; i < limit; ++i)
+      myBitEnabled[i] = in.getBool();
+
     myDumpEnabled = in.getBool();
     myDumpDisabledCycle = (Int32) in.getLong();
 
@@ -2150,10 +2165,10 @@ void TIA::poke(uInt16 addr, uInt8 value)
     {
       myPF = (myPF & 0x000FFFF0) | ((value >> 4) & 0x0F);
 
-      if(myPF != 0)
-        myEnabledObjects |= myPFBit;
-      else
+      if(!myBitEnabled[TIA::PF] || myPF == 0)
         myEnabledObjects &= ~myPFBit;
+      else
+        myEnabledObjects |= myPFBit;
 
       break;
     }
@@ -2162,10 +2177,10 @@ void TIA::poke(uInt16 addr, uInt8 value)
     {
       myPF = (myPF & 0x000FF00F) | ((uInt32)value << 4);
 
-      if(myPF != 0)
-        myEnabledObjects |= myPFBit;
-      else
+      if(!myBitEnabled[TIA::PF] || myPF == 0)
         myEnabledObjects &= ~myPFBit;
+      else
+        myEnabledObjects |= myPFBit;
 
       break;
     }
@@ -2174,10 +2189,10 @@ void TIA::poke(uInt16 addr, uInt8 value)
     {
       myPF = (myPF & 0x00000FFF) | ((uInt32)value << 12);
 
-      if(myPF != 0)
-        myEnabledObjects |= myPFBit;
-      else
+      if(!myBitEnabled[TIA::PF] || myPF == 0)
         myEnabledObjects &= ~myPFBit;
+      else
+        myEnabledObjects |= myPFBit;
 
       break;
     }
@@ -2385,7 +2400,7 @@ void TIA::poke(uInt16 addr, uInt8 value)
     case 0x1B:    // Graphics Player 0
     {
       // Set player 0 graphics
-      myGRP0 = value;
+      myGRP0 = (myBitEnabled[TIA::P0] ? value : 0);
 
       // Copy player 1 graphics into its delayed register
       myDGRP1 = myGRP1;
@@ -2415,7 +2430,7 @@ void TIA::poke(uInt16 addr, uInt8 value)
     case 0x1C:    // Graphics Player 1
     {
       // Set player 1 graphics
-      myGRP1 = value;
+      myGRP1 = (myBitEnabled[TIA::P1] ? value : 0);
 
       // Copy player 0 graphics into its delayed register
       myDGRP0 = myGRP0;
@@ -2450,9 +2465,9 @@ void TIA::poke(uInt16 addr, uInt8 value)
       break;
     }
 
-    case 0x1D:    // Enable Missle 0 graphics
+    case 0x1D:    // Enable Missile 0 graphics
     {
-      myENAM0 = value & 0x02;
+      myENAM0 = (myBitEnabled[TIA::M0] ? value & 0x02 : 0);
 
       if(myENAM0 && !myRESMP0)
         myEnabledObjects |= myM0Bit;
@@ -2461,9 +2476,9 @@ void TIA::poke(uInt16 addr, uInt8 value)
       break;
     }
 
-    case 0x1E:    // Enable Missle 1 graphics
+    case 0x1E:    // Enable Missile 1 graphics
     {
-      myENAM1 = value & 0x02;
+      myENAM1 = (myBitEnabled[TIA::M1] ? value & 0x02 : 0);
 
       if(myENAM1 && !myRESMP1)
         myEnabledObjects |= myM1Bit;
@@ -2474,7 +2489,7 @@ void TIA::poke(uInt16 addr, uInt8 value)
 
     case 0x1F:    // Enable Ball graphics
     {
-      myENABL = value & 0x02;
+      myENABL = (myBitEnabled[TIA::BL] ? value & 0x02 : 0);
 
       if(myVDELBL ? myDENABL : myENABL)
         myEnabledObjects |= myBLBit;
diff --git a/stella/src/emucore/TIA.hxx b/stella/src/emucore/TIA.hxx
index 8f7706463..9cd46db9f 100644
--- a/stella/src/emucore/TIA.hxx
+++ b/stella/src/emucore/TIA.hxx
@@ -13,7 +13,7 @@
 // See the file "license" for information on usage and redistribution of
 // this file, and for a DISCLAIMER OF ALL WARRANTIES.
 //
-// $Id: TIA.hxx,v 1.16 2005-02-21 20:43:25 stephena Exp $
+// $Id: TIA.hxx,v 1.17 2005-04-21 18:55:15 stephena Exp $
 //============================================================================
 
 #ifndef TIA_HXX
@@ -42,7 +42,7 @@ class Settings;
   be displayed on screen.
 
   @author  Bradford W. Mott
-  @version $Id: TIA.hxx,v 1.16 2005-02-21 20:43:25 stephena Exp $
+  @version $Id: TIA.hxx,v 1.17 2005-04-21 18:55:15 stephena Exp $
 */
 class TIA : public Device , public MediaSource
 {
@@ -171,6 +171,29 @@ class TIA : public Device , public MediaSource
     */
     uInt32 scanlines() const;
 
+    enum TIABit {
+      P0,   // Descriptor for Player 0 Bit
+      M0,   // Descriptor for Missle 0 Bit
+      P1,   // Descriptor for Player 1 Bit
+      M1,   // Descriptor for Missle 1 Bit
+      BL,   // Descriptor for Ball Bit
+      PF    // Descriptor for Playfield Bit
+    };
+
+    /**
+      Enables/disables the specified TIA bit.
+
+      @return  Whether the bit was enabled or disabled
+    */
+    bool enableBit(TIABit b, bool mode) { myBitEnabled[b] = mode; return mode; }
+
+    /**
+      Toggles the specified TIA bit.
+
+      @return  Whether the bit was enabled or disabled
+    */
+    bool toggleBit(TIABit b) { myBitEnabled[b] = !myBitEnabled[b]; return myBitEnabled[b]; }
+
   private:
     // Compute the ball mask table
     void computeBallMaskTable();
@@ -313,7 +336,7 @@ class TIA : public Device , public MediaSource
     bool myREFP0;         // Indicates if player 0 is being reflected
     bool myREFP1;         // Indicates if player 1 is being reflected
 
-    uInt32 myPF;           // Playfield graphics (19-12:PF2 11-4:PF1 3-0:PF0)
+    uInt32 myPF;          // Playfield graphics (19-12:PF2 11-4:PF1 3-0:PF0)
 
     uInt8 myGRP0;         // Player 0 graphics register
     uInt8 myGRP1;         // Player 1 graphics register
@@ -404,6 +427,9 @@ class TIA : public Device , public MediaSource
     // Counter used for TIA M0 "bug" 
     uInt32 myM0CosmicArkCounter;
 
+    // Answers whether specified bits (from TIABit) are enabled or disabled
+    bool myBitEnabled[6];
+
   private:
     // Ball mask table (entries are true or false)
     static uInt8 ourBallMaskTable[4][4][320];