Updated VDP to handle GameGear. Added Turbo mode. Versio 1.0 me thinks!

Core/Cpu/Z80.cs

@@ -1303,6 +1303,35 @@ namespace Core.Cpu
 
             switch (extendedOpcode)
             {
+                case 0x40: // IN B, (C)
+                    {
+                        byte inVal40 = ReadPort(BC.Word);
+                        BC.High = inVal40;
+
+                        byte flags40 = (byte)(AF.Low & 0x01); // Preserve Carry
+                        if ((inVal40 & 0x80) != 0) flags40 |= 0x80; // S
+                        if (inVal40 == 0) flags40 |= 0x40;          // Z
+                        flags40 |= ParityTable[inVal40];            // P/V
+                        flags40 |= (byte)(inVal40 & 0x28);          // Undocumented bits 3 and 5
+
+                        AF.Low = flags40;
+                        return 12;
+                    }
+
+                case 0x50: // IN D, (C)
+                    {
+                        byte inVal50 = ReadPort(BC.Word);
+                        DE.High = inVal50;
+
+                        byte flags50 = (byte)(AF.Low & 0x01); // Preserve Carry
+                        if ((inVal50 & 0x80) != 0) flags50 |= 0x80; // S
+                        if (inVal50 == 0) flags50 |= 0x40;          // Z
+                        flags50 |= ParityTable[inVal50];            // P/V
+                        flags50 |= (byte)(inVal50 & 0x28);          // Undocumented bits 3 and 5
+
+                        AF.Low = flags50;
+                        return 12;
+                    }
                 case 0x41: // OUT (C), B
                     _simpleIoBus.WritePort(BC.Word, BC.High);
                     return 12;

Core/Io/SmsIoBus.cs

@@ -25,7 +25,11 @@ namespace Core.Io
                 // VDP V-Counter (Vertical Scanline Position)
                 return VideoProcessor.ReadVCounter();
             }
-
+            if (lowerPort == 0x7F)
+            {
+                // THE FIX: VDP H-Counter (Horizontal Pixel Position)
+                return VideoProcessor.ReadHCounter();
+            }
             if (lowerPort >= 0x80 && lowerPort <= 0xBF)
             {
                 // Even ports (like 0xBE) are Data. Odd ports (like 0xBF) are Control.

Core/SmsMachine.cs

@@ -23,7 +23,7 @@ namespace Core
         //public const int TStatesPerFrame = 49780; //PAL
 
         public SmsMachine()
-        {
+        { 
             MemoryBus = new SmsMemoryBus();
             VideoProcessor = new SmsVdp();
             AudioProcessor = new SmsApu();

Core/Video/SmsVdp.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Diagnostics;
 using System.IO;
 
 namespace Core.Video
@@ -7,7 +8,8 @@ namespace Core.Video
     {
         // The VDP's private memory! The CPU cannot touch these arrays directly.
         public byte[] VRAM { get; private set; } = new byte[0x4000]; // 16KB Video RAM
-        public byte[] CRAM { get; private set; } = new byte[0x20];   // 32 Bytes Color Palette
+        public byte[] smsCRAM { get; private set; } = new byte[0x20];   // Master System - 32 Bytes colour Palette
+        public byte[] ggCRAM { get; private set; } = new byte[0x40]; // GameGear - 64 Bytes colour palette
         public byte[] Registers { get; private set; } = new byte[16]; // 11 Hardware Control Registers
         public int[] FrameBuffer { get; private set; } = new int[256 * 192];
         private bool[] _priorityBuffer = new bool[256 * 192]; // Tracks priority pixels!
@@ -25,11 +27,14 @@ namespace Core.Video
         private int _currentScanline = 0;
         private int _lineCounter = 0;
         private byte _statusRegister = 0x00;
+        public bool IsGameGear { get; set; } = false;
 
         public bool InterruptPending =>
             ((_statusRegister & 0x80) != 0 && (Registers[1] & 0x20) != 0) || // VBlank
             ((_statusRegister & 0x40) != 0 && (Registers[0] & 0x10) != 0);   // Line Interrupt
 
+        
+
         public byte ReadDataPort() // Port 0xBE
         {
             _isSecondControlByte = false; // Reading data resets the control latch
@@ -44,8 +49,8 @@ namespace Core.Video
             _isSecondControlByte = false;
             byte currentStatus = _statusRegister;
 
-            // CRITICAL HARDWARE QUIRK: Reading the status port physically 
+            // Reading the status port physically 
-            // clears the flags inside the chip! If we don't clear this, 
+            // clears the flags inside the chip If we don't clear this, 
             // the interrupt line gets stuck on forever.
             _statusRegister = 0x00;
 
@@ -55,20 +60,29 @@ namespace Core.Video
         public void WriteDataPort(byte value) // Port 0xBE
         {
             _isSecondControlByte = false;
-            _readBuffer = value; 
+            _readBuffer = value;
 
             int address = _controlWord & 0x3FFF;
             int command = (_controlWord >> 14) & 0x03;
 
-            if (command == 3) // Code 3: Write to Color Palette (CRAM)
+            if (command == 3) // Code 3: Write to Colour Palette (CRAM)
             {
-                CRAM[address & 0x1F] = value;
+                if (IsGameGear)
+                {
+                    ggCRAM[address & 0x3F] = value; // GG has 64 bytes of CRAM
+                }
+                else
+                {
+                    smsCRAM[address & 0x1F] = value; // SMS has 32 bytes of CRAM
+                }
             }
-            else // Code 0, 1, 2: Write to VRAM
+            else // THE FIX: Code 0, 1, 2: Write graphics to VRAM!
             {
                 VRAM[address] = value;
             }
-            _controlWord++; // Auto-increment so the Z80 can blast data fast
+
+            // THE FIX: The pointer MUST auto-increment so the CPU can blast data fast!
+            _controlWord++;
         }
 
         public void WriteControlPort(byte value) // Port 0xBF
@@ -104,10 +118,28 @@ namespace Core.Video
 
         public byte ReadVCounter()
         {
-            // Note: On real NTSC hardware, the V-Counter jumps slightly around 
+             // NTSC Math: 262 lines. Counts 0 to 218, jumps to 213 (0xD5), counts to 255.
-            // the VBlank period to keep the math 8-bit, but simply returning 
+                if (_currentScanline <= 218) return (byte)_currentScanline;
-            // the raw current scanline is perfectly fine to get us booting!
+                else return (byte)(_currentScanline - 6);
-            return (byte)_currentScanline;
+            
+        }
+        public byte ReadHCounter()
+        {
+            // The Master System H-Counter counts from 0x00 to 0x93, then jumps forward to 0xE9, ending at 0xFF.
+
+            // 1 T-State = 1.5 pixels. The H-Counter increments every 2 pixels.
+            // So H = T * 0.75
+            int h = (int)(_tStateCounter * 0.75);
+
+            if (h <= 0x93)
+            {
+                return (byte)h;
+            }
+            else
+            {
+                // Emulate the hardware jump!
+                return (byte)(h - 0x94 + 0xE9);
+            }
         }
 
         public void Update(int tStates)
@@ -145,7 +177,9 @@ namespace Core.Video
                 // 3. MOVE TO THE NEXT LINE
                 _currentScanline++;
 
-                if (_currentScanline > 261)
+                int maxLines = 262;
+
+                if (_currentScanline > maxLines -1)
                 {
                     _currentScanline = 0;
                 }
@@ -167,7 +201,6 @@ namespace Core.Video
                 for (int x = 0; x < 256; x++) FrameBuffer[(screenY * 256) + x] = unchecked((int)0xFF000000);
                 return;
             }
-
             // --- 1. RENDER BACKGROUND LINE ---
             ushort nameTableBase = (ushort)((Registers[2] & 0x0E) << 10);
             int scrollX = Registers[8]; 
@@ -183,16 +216,10 @@ namespace Core.Video
                 // --- LEFT COLUMN MASKING (OVERSCAN CURTAIN) ---
                 if (maskLeftCol && screenX < 8)
                 {
-                    // Draw the physical backdrop color (from Sprite Palette + Reg 7 index)
+                    // REPLACE THE R/G/B MATH WITH THIS SINGLE LINE:
-                    byte bgSmsColor = CRAM[16 + (Registers[7] & 0x0F)];
-                    int bgR = (bgSmsColor & 0x03) * 85;
-                    int bgG = ((bgSmsColor >> 2) & 0x03) * 85;
-                    int bgB = ((bgSmsColor >> 4) & 0x03) * 85;
-
                     int bgAddress = (screenY * 256) + screenX;
-                    FrameBuffer[bgAddress] = (255 << 24) | (bgR << 16) | (bgG << 8) | bgB;
+                    FrameBuffer[bgAddress] = GetRgbColour(16, Registers[7] & 0x0F);
 
-                    // Flag it as priority so sprites also hide behind the curtain!
                     _priorityBuffer[bgAddress] = true;
                     continue;
                 }
@@ -231,21 +258,17 @@ namespace Core.Video
                 byte bp3 = VRAM[tileAddress + (readY * 4) + 3];
 
                 int readX = flipH ? tileX : (7 - tileX);
-                int colorIndex = ((bp0 >> readX) & 1) | (((bp1 >> readX) & 1) << 1) |
+                int colourIndex = ((bp0 >> readX) & 1) | (((bp1 >> readX) & 1) << 1) |
                                  (((bp2 >> readX) & 1) << 2) | (((bp3 >> readX) & 1) << 3);
 
                 int paletteOffset = useSpritePalette ? 16 : 0;
-                byte smsColor = CRAM[paletteOffset + colorIndex];
+                int finalColour = GetRgbColour(paletteOffset, colourIndex);
-
-                int r = (smsColor & 0x03) * 85;
-                int g = ((smsColor >> 2) & 0x03) * 85;
-                int b = ((smsColor >> 4) & 0x03) * 85;
 
                 int screenAddress = (screenY * 256) + screenX;
 
                 // Draw background and reset priority mask for this exact pixel
-                FrameBuffer[screenAddress] = (255 << 24) | (r << 16) | (g << 8) | b;
+                FrameBuffer[screenAddress] = finalColour;
-                _priorityBuffer[screenAddress] = (priority && colorIndex != 0);
+                _priorityBuffer[screenAddress] = (priority && colourIndex != 0);
             }
 
             // --- 2. RENDER SPRITE LINE ---
@@ -299,24 +322,53 @@ namespace Core.Video
                     if (_priorityBuffer[(screenY * 256) + screenX]) continue;
 
                     int shift = 7 - px;
-                    int colorIndex = ((bp0 >> shift) & 1) | (((bp1 >> shift) & 1) << 1) |
+                    int colourIndex = ((bp0 >> shift) & 1) | (((bp1 >> shift) & 1) << 1) |
                                      (((bp2 >> shift) & 1) << 2) | (((bp3 >> shift) & 1) << 3);
 
-                    if (colorIndex == 0) continue;
+                    if (colourIndex == 0) continue;
 
-                    byte smsColor = CRAM[16 + colorIndex];
+                    // REPLACE THE R/G/B MATH WITH THIS SINGLE LINE:
-                    int r = (smsColor & 0x03) * 85;
+                    FrameBuffer[(screenY * 256) + screenX] = GetRgbColour(16, colourIndex);
-                    int g = ((smsColor >> 2) & 0x03) * 85;
-                    int b = ((smsColor >> 4) & 0x03) * 85;
-
-                    FrameBuffer[(screenY * 256) + screenX] = (255 << 24) | (r << 16) | (g << 8) | b;
                 }
             }
         }
+
+        public int GetRgbColour(int paletteOffset, int colourIndex)
+        {
+            //Debug.WriteLine(_isGameGear);
+            int r, g, b;
+
+            if (IsGameGear)
+            {
+                // Game Gear: 2 bytes per colour. Format: ----BBBBGGGGRRRR
+                int cramIndex = (paletteOffset + colourIndex) * 2;
+                ushort ggcolour = (ushort)(ggCRAM[cramIndex] | (ggCRAM[cramIndex + 1] << 8));
+
+                // Extract 4-bit values (0-15) and map them to standard 8-bit values (0-255). 
+                // We multiply by 17 because 255 / 15 = 17!
+                r = (ggcolour & 0x0F) * 17;
+                g = ((ggcolour >> 4) & 0x0F) * 17;
+                b = ((ggcolour >> 8) & 0x0F) * 17;
+            }
+            else
+            {
+                // Master System: 1 byte per colour. Format: --BBGGRR
+                byte smscolour = smsCRAM[paletteOffset + colourIndex];
+
+                // Extract 2-bit values (0-3) and map them to standard 8-bit values (0-255).
+                // We multiply by 85 because 255 / 3 = 85!
+                r = (smscolour & 0x03) * 85;
+                g = ((smscolour >> 2) & 0x03) * 85;
+                b = ((smscolour >> 4) & 0x03) * 85;
+            }
+
+            return (255 << 24) | (r << 16) | (g << 8) | b;
+        }
         public void SaveState(BinaryWriter bw)
         {
             bw.Write(VRAM);
-            bw.Write(CRAM);
+            bw.Write(smsCRAM);
+            bw.Write(ggCRAM);
             bw.Write(Registers);
             bw.Write(_isSecondControlByte);
             bw.Write(_controlWord);
@@ -329,12 +381,14 @@ namespace Core.Video
             // ADD THESE:
             bw.Write(_latchedHScroll);
             bw.Write(_latchedVScroll);
+            bw.Write(IsGameGear);
         }
 
         public void LoadState(BinaryReader br)
         {
             Array.Copy(br.ReadBytes(VRAM.Length), VRAM, VRAM.Length);
-            Array.Copy(br.ReadBytes(CRAM.Length), CRAM, CRAM.Length);
+            Array.Copy(br.ReadBytes(smsCRAM.Length), smsCRAM, smsCRAM.Length);
+            Array.Copy(br.ReadBytes(ggCRAM.Length), ggCRAM, ggCRAM.Length);
             Array.Copy(br.ReadBytes(Registers.Length), Registers, Registers.Length);
             _isSecondControlByte = br.ReadBoolean();
             _controlWord = br.ReadUInt16();
@@ -347,6 +401,7 @@ namespace Core.Video
             // ADD THESE:
             _latchedHScroll = br.ReadInt32();
             _latchedVScroll = br.ReadInt32();
+            IsGameGear = br.ReadBoolean();
         }
     }
 }

Desktop/Desktop.csproj

@@ -15,6 +15,14 @@
 		<RuntimeIdentifier>win-x64</RuntimeIdentifier>
 		<StartupObject>Desktop.Program</StartupObject>
 		<AssemblyName>Parsons Master System</AssemblyName>
+		<ApplicationIcon>favicon.ico</ApplicationIcon>
+		<Title>Sega Master System EMulator 2026</Title>
+		<Version>0.9</Version>
+		<Authors>Marc Parsons</Authors>
+		<Company>Parsons Limited</Company>
+		<Description>Parsons Master System 2026</Description>
+		<Copyright>Copyright 2026 Marc Parsons</Copyright>
+		<PackageIcon>logo1.bmp</PackageIcon>
 	</PropertyGroup>
 
 	<ItemGroup>
@@ -42,9 +50,10 @@
 		<None Remove="ROMS\Gangster Town %28UE%29 [!].sms" />
 		<None Remove="ROMS\Gauntlet %28UE%29 [!].sms" />
 		<None Remove="ROMS\Ghost House %28UE%29 [!].sms" />
-		<None Remove="ROMS\Ghouls %27n Ghosts %28UE%29 [!].sms" />
+		<None Remove="ROMS\Ghouls %27n Ghosts %28USA%29.sms" />
 		<None Remove="ROMS\Global Defense %28UE%29 [!].sms" />
 		<None Remove="ROMS\Golden Axe %28UE%29 [!].sms" />
+		<None Remove="ROMS\Golden Axe Warrior.sav" />
 		<None Remove="ROMS\Golden Axe Warrior.sms" />
 		<None Remove="ROMS\Great Baseball %28UE%29 [!].sms" />
 		<None Remove="ROMS\Great Basketball %28UE%29 [!].sms" />
@@ -65,7 +74,8 @@
 		<None Remove="ROMS\Mortal Kombat %28UE%29 [!].sms" />
 		<None Remove="ROMS\Mortal Kombat 2 %28UE%29 [!].sms" />
 		<None Remove="ROMS\Mortal Kombat 3 %28UE%29 [!].sms" />
-		<None Remove="ROMS\OutRun %28UE%29 [!].sms" />
+		<None Remove="ROMS\Olympic Gold - Barcelona %2792 %28Europe%29.sms" />
+		<None Remove="ROMS\OutRun %28USA%29.sms" />
 		<None Remove="ROMS\Paperboy %28UE%29 [!].sms" />
 		<None Remove="ROMS\Parlour Games %28UE%29 [!].sms" />
 		<None Remove="ROMS\Phantasy Star %28UE%29 [!].sms" />
@@ -77,10 +87,11 @@
 		<None Remove="ROMS\Shadow of the Beast %28UE%29 [!].sms" />
 		<None Remove="ROMS\Smash TV %28UE%29 [!].sms" />
 		<None Remove="ROMS\SMSTestSuite.sms" />
+		<None Remove="ROMS\Sonic 1 GG.gg" />
 		<None Remove="ROMS\Sonic 2.sms" />
 		<None Remove="ROMS\Sonic Chaos %28UE%29 [!].sms" />
 		<None Remove="ROMS\Sonic.sms" />
-		<None Remove="ROMS\Space Harrier %28UE%29 [!].sms" />
+		<None Remove="ROMS\Space Harrier %28USA%29.sms" />
 		<None Remove="ROMS\Speedball %28UE%29 %28Virgin%29 [!].sms" />
 		<None Remove="ROMS\Star Wars %28UE%29 [!].sms" />
 		<None Remove="ROMS\Street Fighter 2 %28Brazil%29 [!].sms" />
@@ -103,6 +114,10 @@
 		<None Remove="ROMS\zexdoc.sms" />
 	</ItemGroup>
 
+	<ItemGroup>
+	  <Content Include="favicon.ico" />
+	</ItemGroup>
+
 	<ItemGroup>
 		<EmbeddedResource Include="ROMS\After Burner (UE) [!].sms">
 			<CopyToOutputDirectory>Never</CopyToOutputDirectory>
@@ -176,15 +191,14 @@
 		<EmbeddedResource Include="ROMS\Ghost House (UE) [!].sms">
 			<CopyToOutputDirectory>Never</CopyToOutputDirectory>
 		</EmbeddedResource>
-		<EmbeddedResource Include="ROMS\Ghouls 'n Ghosts (UE) [!].sms">
+		<EmbeddedResource Include="ROMS\Ghouls 'n Ghosts (USA).sms" />
-			<CopyToOutputDirectory>Never</CopyToOutputDirectory>
-		</EmbeddedResource>
 		<EmbeddedResource Include="ROMS\Global Defense (UE) [!].sms">
 			<CopyToOutputDirectory>Never</CopyToOutputDirectory>
 		</EmbeddedResource>
 		<EmbeddedResource Include="ROMS\Golden Axe (UE) [!].sms">
 			<CopyToOutputDirectory>Never</CopyToOutputDirectory>
 		</EmbeddedResource>
+		<EmbeddedResource Include="ROMS\Golden Axe Warrior.sav" />
 		<EmbeddedResource Include="ROMS\Golden Axe Warrior.sms">
 			<CopyToOutputDirectory>Never</CopyToOutputDirectory>
 		</EmbeddedResource>
@@ -245,9 +259,8 @@
 		<EmbeddedResource Include="ROMS\Mortal Kombat 3 (UE) [!].sms">
 			<CopyToOutputDirectory>Never</CopyToOutputDirectory>
 		</EmbeddedResource>
-		<EmbeddedResource Include="ROMS\OutRun (UE) [!].sms">
+		<EmbeddedResource Include="ROMS\Olympic Gold - Barcelona '92 (Europe).sms" />
-			<CopyToOutputDirectory>Never</CopyToOutputDirectory>
+		<EmbeddedResource Include="ROMS\OutRun (USA).sms" />
-		</EmbeddedResource>
 		<EmbeddedResource Include="ROMS\Paperboy (UE) [!].sms">
 			<CopyToOutputDirectory>Never</CopyToOutputDirectory>
 		</EmbeddedResource>
@@ -281,6 +294,7 @@
 		<EmbeddedResource Include="ROMS\SMSTestSuite.sms">
 			<CopyToOutputDirectory>Never</CopyToOutputDirectory>
 		</EmbeddedResource>
+		<EmbeddedResource Include="ROMS\Sonic 1 GG.gg" />
 		<EmbeddedResource Include="ROMS\Sonic 2.sms">
 			<CopyToOutputDirectory>Never</CopyToOutputDirectory>
 		</EmbeddedResource>
@@ -290,9 +304,7 @@
 		<EmbeddedResource Include="ROMS\Sonic.sms">
 			<CopyToOutputDirectory>Never</CopyToOutputDirectory>
 		</EmbeddedResource>
-		<EmbeddedResource Include="ROMS\Space Harrier (UE) [!].sms">
+		<EmbeddedResource Include="ROMS\Space Harrier (USA).sms" />
-			<CopyToOutputDirectory>Never</CopyToOutputDirectory>
-		</EmbeddedResource>
 		<EmbeddedResource Include="ROMS\Speedball (UE) (Virgin) [!].sms">
 			<CopyToOutputDirectory>Never</CopyToOutputDirectory>
 		</EmbeddedResource>
@@ -353,6 +365,13 @@
 		</EmbeddedResource>
 	</ItemGroup>
 
+	<ItemGroup>
+	  <None Include="..\logo1.bmp">
+	    <Pack>True</Pack>
+	    <PackagePath>\</PackagePath>
+	  </None>
+	</ItemGroup>
+
 	<ItemGroup>
 		<PackageReference Include="NAudio" Version="2.3.0" />
 		<PackageReference Include="Vortice.XInput" Version="3.8.3" />

Desktop/Form1.Designer.cs

@@ -39,10 +39,13 @@
             vRAMViewerToolStripMenuItem = new ToolStripMenuItem();
             machineToolStripMenuItem = new ToolStripMenuItem();
             resetToolStripMenuItem = new ToolStripMenuItem();
-            helpToolStripMenuItem = new ToolStripMenuItem();
-            aboutToolStripMenuItem = new ToolStripMenuItem();
             saveStateToolStripMenuItem = new ToolStripMenuItem();
             loadStateToolStripMenuItem = new ToolStripMenuItem();
+            turboModeToolStripMenuItem = new ToolStripMenuItem();
+            helpToolStripMenuItem = new ToolStripMenuItem();
+            aboutToolStripMenuItem = new ToolStripMenuItem();
+            masterSystemToolStripMenuItem = new ToolStripMenuItem();
+            gameGearToolStripMenuItem = new ToolStripMenuItem();
             menuStrip1.SuspendLayout();
             SuspendLayout();
             // 
@@ -52,7 +55,8 @@
             menuStrip1.Items.AddRange(new ToolStripItem[] { fileToolStripMenuItem, viewToolStripMenuItem, machineToolStripMenuItem, helpToolStripMenuItem });
             menuStrip1.Location = new Point(0, 0);
             menuStrip1.Name = "menuStrip1";
-            menuStrip1.Size = new Size(791, 33);
+            menuStrip1.Padding = new Padding(5, 2, 0, 2);
+            menuStrip1.Size = new Size(633, 28);
             menuStrip1.TabIndex = 2;
             menuStrip1.Text = "menuStrip1";
             // 
@@ -60,34 +64,34 @@
             // 
             fileToolStripMenuItem.DropDownItems.AddRange(new ToolStripItem[] { openToolStripMenuItem, exitToolStripMenuItem });
             fileToolStripMenuItem.Name = "fileToolStripMenuItem";
-            fileToolStripMenuItem.Size = new Size(54, 29);
+            fileToolStripMenuItem.Size = new Size(46, 24);
             fileToolStripMenuItem.Text = "File";
             // 
             // openToolStripMenuItem
             // 
             openToolStripMenuItem.DropDownItems.AddRange(new ToolStripItem[] { includedToolStripMenuItem, selectROMToolStripMenuItem1 });
             openToolStripMenuItem.Name = "openToolStripMenuItem";
-            openToolStripMenuItem.Size = new Size(158, 34);
+            openToolStripMenuItem.Size = new Size(224, 26);
             openToolStripMenuItem.Text = "Open";
             // 
             // includedToolStripMenuItem
             // 
+            includedToolStripMenuItem.DropDownItems.AddRange(new ToolStripItem[] { masterSystemToolStripMenuItem, gameGearToolStripMenuItem });
             includedToolStripMenuItem.Name = "includedToolStripMenuItem";
-            includedToolStripMenuItem.Size = new Size(218, 34);
+            includedToolStripMenuItem.Size = new Size(224, 26);
             includedToolStripMenuItem.Text = "Included";
-            includedToolStripMenuItem.Click += includedToolStripMenuItem_Click;
             // 
             // selectROMToolStripMenuItem1
             // 
             selectROMToolStripMenuItem1.Name = "selectROMToolStripMenuItem1";
-            selectROMToolStripMenuItem1.Size = new Size(218, 34);
+            selectROMToolStripMenuItem1.Size = new Size(224, 26);
             selectROMToolStripMenuItem1.Text = "Select ROM...";
             selectROMToolStripMenuItem1.Click += selectROMToolStripMenuItem_Click;
             // 
             // exitToolStripMenuItem
             // 
             exitToolStripMenuItem.Name = "exitToolStripMenuItem";
-            exitToolStripMenuItem.Size = new Size(158, 34);
+            exitToolStripMenuItem.Size = new Size(224, 26);
             exitToolStripMenuItem.Text = "Exit";
             exitToolStripMenuItem.Click += exitToolStripMenuItem_Click;
             // 
@@ -95,72 +99,90 @@
             // 
             viewToolStripMenuItem.DropDownItems.AddRange(new ToolStripItem[] { debuggerToolStripMenuItem, vRAMViewerToolStripMenuItem });
             viewToolStripMenuItem.Name = "viewToolStripMenuItem";
-            viewToolStripMenuItem.Size = new Size(65, 29);
+            viewToolStripMenuItem.Size = new Size(55, 24);
             viewToolStripMenuItem.Text = "View";
             // 
             // debuggerToolStripMenuItem
             // 
             debuggerToolStripMenuItem.Name = "debuggerToolStripMenuItem";
-            debuggerToolStripMenuItem.Size = new Size(221, 34);
+            debuggerToolStripMenuItem.Size = new Size(182, 26);
             debuggerToolStripMenuItem.Text = "Debugger";
             debuggerToolStripMenuItem.Click += debuggerToolStripMenuItem_Click;
             // 
             // vRAMViewerToolStripMenuItem
             // 
             vRAMViewerToolStripMenuItem.Name = "vRAMViewerToolStripMenuItem";
-            vRAMViewerToolStripMenuItem.Size = new Size(221, 34);
+            vRAMViewerToolStripMenuItem.Size = new Size(182, 26);
             vRAMViewerToolStripMenuItem.Text = "VRAM Viewer";
             vRAMViewerToolStripMenuItem.Click += vramViewerToolStripMenuItem_Click;
             // 
             // machineToolStripMenuItem
             // 
-            machineToolStripMenuItem.DropDownItems.AddRange(new ToolStripItem[] { resetToolStripMenuItem, saveStateToolStripMenuItem, loadStateToolStripMenuItem });
+            machineToolStripMenuItem.DropDownItems.AddRange(new ToolStripItem[] { resetToolStripMenuItem, saveStateToolStripMenuItem, loadStateToolStripMenuItem, turboModeToolStripMenuItem });
             machineToolStripMenuItem.Name = "machineToolStripMenuItem";
-            machineToolStripMenuItem.Size = new Size(94, 29);
+            machineToolStripMenuItem.Size = new Size(79, 24);
             machineToolStripMenuItem.Text = "Machine";
             // 
             // resetToolStripMenuItem
             // 
             resetToolStripMenuItem.Name = "resetToolStripMenuItem";
-            resetToolStripMenuItem.Size = new Size(270, 34);
+            resetToolStripMenuItem.Size = new Size(224, 26);
             resetToolStripMenuItem.Text = "Reset";
             resetToolStripMenuItem.Click += resetToolStripMenuItem_Click;
             // 
-            // helpToolStripMenuItem
-            // 
-            helpToolStripMenuItem.DropDownItems.AddRange(new ToolStripItem[] { aboutToolStripMenuItem });
-            helpToolStripMenuItem.Name = "helpToolStripMenuItem";
-            helpToolStripMenuItem.Size = new Size(65, 29);
-            helpToolStripMenuItem.Text = "Help";
-            // 
-            // aboutToolStripMenuItem
-            // 
-            aboutToolStripMenuItem.Name = "aboutToolStripMenuItem";
-            aboutToolStripMenuItem.Size = new Size(164, 34);
-            aboutToolStripMenuItem.Text = "About";
-            // 
             // saveStateToolStripMenuItem
             // 
             saveStateToolStripMenuItem.Name = "saveStateToolStripMenuItem";
-            saveStateToolStripMenuItem.Size = new Size(270, 34);
+            saveStateToolStripMenuItem.Size = new Size(224, 26);
             saveStateToolStripMenuItem.Text = "Save State";
             saveStateToolStripMenuItem.Click += saveStateToolStripMenuItem_Click;
             // 
             // loadStateToolStripMenuItem
             // 
             loadStateToolStripMenuItem.Name = "loadStateToolStripMenuItem";
-            loadStateToolStripMenuItem.Size = new Size(270, 34);
+            loadStateToolStripMenuItem.Size = new Size(224, 26);
             loadStateToolStripMenuItem.Text = "Load State";
             loadStateToolStripMenuItem.Click += loadStateToolStripMenuItem_Click;
             // 
+            // turboModeToolStripMenuItem
+            // 
+            turboModeToolStripMenuItem.Name = "turboModeToolStripMenuItem";
+            turboModeToolStripMenuItem.Size = new Size(224, 26);
+            turboModeToolStripMenuItem.Text = "Turbo Mode";
+            turboModeToolStripMenuItem.Click += turboModeToolStripMenuItem_Click;
+            // 
+            // helpToolStripMenuItem
+            // 
+            helpToolStripMenuItem.DropDownItems.AddRange(new ToolStripItem[] { aboutToolStripMenuItem });
+            helpToolStripMenuItem.Name = "helpToolStripMenuItem";
+            helpToolStripMenuItem.Size = new Size(55, 24);
+            helpToolStripMenuItem.Text = "Help";
+            // 
+            // aboutToolStripMenuItem
+            // 
+            aboutToolStripMenuItem.Name = "aboutToolStripMenuItem";
+            aboutToolStripMenuItem.Size = new Size(133, 26);
+            aboutToolStripMenuItem.Text = "About";
+            // 
+            // masterSystemToolStripMenuItem
+            // 
+            masterSystemToolStripMenuItem.Name = "masterSystemToolStripMenuItem";
+            masterSystemToolStripMenuItem.Size = new Size(224, 26);
+            masterSystemToolStripMenuItem.Text = "Master System";
+            // 
+            // gameGearToolStripMenuItem
+            // 
+            gameGearToolStripMenuItem.Name = "gameGearToolStripMenuItem";
+            gameGearToolStripMenuItem.Size = new Size(224, 26);
+            gameGearToolStripMenuItem.Text = "Game Gear";
+            // 
             // ParsonsForm1
             // 
-            AutoScaleDimensions = new SizeF(10F, 25F);
+            AutoScaleDimensions = new SizeF(8F, 20F);
             AutoScaleMode = AutoScaleMode.Font;
-            ClientSize = new Size(791, 622);
+            ClientSize = new Size(633, 498);
             Controls.Add(menuStrip1);
             MainMenuStrip = menuStrip1;
-            Margin = new Padding(4);
             Name = "ParsonsForm1";
             Text = "Form1";
             FormClosing += ParsonsForm1_FormClosing;
@@ -186,5 +208,8 @@
         private ToolStripMenuItem vRAMViewerToolStripMenuItem;
         private ToolStripMenuItem saveStateToolStripMenuItem;
         private ToolStripMenuItem loadStateToolStripMenuItem;
+        private ToolStripMenuItem turboModeToolStripMenuItem;
+        private ToolStripMenuItem masterSystemToolStripMenuItem;
+        private ToolStripMenuItem gameGearToolStripMenuItem;
     }
 }

Desktop/Form1.cs

@@ -18,14 +18,14 @@ namespace Desktop
         private Bitmap _screenBitmap = new Bitmap(256, 192, PixelFormat.Format32bppArgb);
         private NAudioPlayer _audioPlayer;
         private Task _emulatorTask;
-        private double TargetFrameTime = 16.667f; //NTSC
-        //private double TargetFrameTime = 20; //PAL
         public int TotalFrameCount = 0;
         public double FrameTime { get; private set; } = 0;
         public double FramesPerSecond { get; private set; } = 0;
         private string _currentRomName = "No ROM";
         private string _currentRomPath = "";
-        private Stopwatch _stopwatch = new System.Diagnostics.Stopwatch();
+        private Stopwatch _stopwatch = new Stopwatch();
+        private string _romType = "";
+        private bool isTurboMode = false;
         public bool IsRunning { get; private set; } = false;
 
         public ushort? Breakpoint
@@ -37,23 +37,19 @@ namespace Desktop
         public ParsonsForm1()
         {
             InitializeComponent();
-
-            // These are perfectly safe for the Visual Studio Designer!
             this.KeyPreview = true;
             this.KeyDown += Form1_KeyDown;
             this.KeyUp += Form1_KeyUp;
             this.DoubleBuffered = true;
             this.ResizeRedraw = true;
         }
-
-        // The Designer ignores this completely, but the compiled game runs it instantly!
         protected override void OnLoad(EventArgs e)
         {
             base.OnLoad(e);
 
-            this.Text = $"Parsons Master System - {_currentRomName}";
+            this.Text = $"Parsons Master System 2026 - {_currentRomName}";
 
-            // Safe to initialize hardware and files here!
+            this.BackColor = Color.Black;
             _machine = new SmsMachine();
             _audioPlayer = new NAudioPlayer();
             _machine.AudioProcessor.AudioDevice = _audioPlayer;
@@ -70,43 +66,101 @@ namespace Desktop
             this.Invalidate();
             TotalFrameCount++;
         }
+
         protected override void OnPaint(PaintEventArgs e)
         {
-            // Always call the base method so Windows can draw your MenuStrip!
             base.OnPaint(e);
 
-            // THE FIX: We MUST ensure the designer has actually built the menu strip before asking for its height!
             if (_screenBitmap != null && menuStrip1 != null)
             {
-                // 1. Set the rendering mode for perfect, chunky retro pixels!
+                // 1. Maintain perfect, chunky retro pixels
                 e.Graphics.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.NearestNeighbor;
                 e.Graphics.PixelOffsetMode = System.Drawing.Drawing2D.PixelOffsetMode.Half;
 
-                // 2. Calculate the drawing area. 
-                // We start drawing BELOW the MenuStrip so it doesn't get covered up.
                 int topOffset = menuStrip1.Height;
-                Rectangle renderArea = new Rectangle(
+                int availableWidth = this.ClientSize.Width;
-                    0,
+                int availableHeight = this.ClientSize.Height - topOffset;
-                    topOffset,
-                    this.ClientSize.Width,
-                    this.ClientSize.Height - topOffset
-                );
 
-                // 3. Blast the bitmap directly onto the graphics card buffer!
+                // 2. THE LENS LENS: Determine what part of the VDP buffer we actually want to show!
-                e.Graphics.DrawImage(_screenBitmap, renderArea);
+                // (Safely check if the machine/video processor exists yet)
+                bool isGG = _machine?.VideoProcessor?.IsGameGear ?? false;
+
+                int sourceWidth = isGG ? 160 : 256;
+                int sourceHeight = isGG ? 144 : 192;
+                int sourceX = isGG ? 48 : 0; // Skip 48 pixels in!
+                int sourceY = isGG ? 24 : 0; // Skip 24 pixels down!
+
+                // Create a rectangle defining the specific pixels to extract from the raw frame buffer
+                Rectangle sourceRect = new Rectangle(sourceX, sourceY, sourceWidth, sourceHeight);
+
+                // 3. Calculate the maximum scale factor for the cropped image
+                float scaleX = (float)availableWidth / sourceWidth;
+                float scaleY = (float)availableHeight / sourceHeight;
+
+                // Pick the smaller scale so the image never bleeds off the edge
+                float scale = Math.Min(scaleX, scaleY);
+
+                // 4. Calculate the new physical pixel dimensions
+                int newWidth = (int)(sourceWidth * scale);
+                int newHeight = (int)(sourceHeight * scale);
+
+                // 5. Center the image (Letterboxing / Pillarboxing)
+                int offsetX = (availableWidth - newWidth) / 2;
+                int offsetY = topOffset + ((availableHeight - newHeight) / 2);
+
+                // Create a rectangle defining exactly where on the Windows form to draw the extracted pixels
+                Rectangle destRect = new Rectangle(offsetX, offsetY, newWidth, newHeight);
+
+                // 6. Blast the perfectly cropped and scaled bitmap onto the screen!
+                e.Graphics.DrawImage(_screenBitmap, destRect, sourceRect, GraphicsUnit.Pixel);
             }
         }
+        //protected override void OnPaint(PaintEventArgs e)
+        //{
+        //    base.OnPaint(e);
+
+        //    if (_screenBitmap != null && menuStrip1 != null)
+        //    {
+        //        // 1. Maintain perfect, chunky retro pixels
+        //        e.Graphics.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.NearestNeighbor;
+        //        e.Graphics.PixelOffsetMode = System.Drawing.Drawing2D.PixelOffsetMode.Half;
+
+        //        // 2. Calculate the actual usable window space
+        //        int topOffset = menuStrip1.Height;
+        //        int availableWidth = this.ClientSize.Width;
+        //        int availableHeight = this.ClientSize.Height - topOffset;
+
+        //        // 3. Calculate the maximum scale factor that fits perfectly
+        //        float scaleX = (float)availableWidth / 256f;
+        //        float scaleY = (float)availableHeight / 192f;
+
+        //        // Pick the smaller scale so the image never bleeds off the edge
+        //        float scale = Math.Min(scaleX, scaleY);
+
+        //        // 4. Calculate the new physical pixel dimensions
+        //        int newWidth = (int)(256 * scale);
+        //        int newHeight = (int)(192 * scale);
+
+        //        // 5. Center the image (Letterboxing / Pillarboxing)
+        //        int offsetX = (availableWidth - newWidth) / 2;
+        //        int offsetY = topOffset + ((availableHeight - newHeight) / 2);
+
+        //        Rectangle renderArea = new Rectangle(offsetX, offsetY, newWidth, newHeight);
+
+        //        // 6. Draw the scaled image
+        //        e.Graphics.DrawImage(_screenBitmap, renderArea);
+        //    }
+        //}
 
         public void StartEmulator()
         {
             if (IsRunning) return;
             IsRunning = true;
             TotalFrameCount = 0;
-
-            double TargetFrameTime = 1000.0 / 59.92274;
-
             _emulatorTask = Task.Run(() =>
             {
+                double targetFps = 59.94;
+                double TargetFrameTime = 1000.0 / targetFps;
                 _stopwatch.Restart();
 
                 double nextFrameTargetTime = _stopwatch.Elapsed.TotalMilliseconds + TargetFrameTime;
@@ -115,7 +169,13 @@ namespace Desktop
 
                 while (IsRunning)
                 {
-                    // Mark exactly when the emulator starts thinking
+                    //targetFps = isTurboMode ? 1000 : 59.94;
+                    //TargetFrameTime = 1000.0 / targetFps;
+                    BeginInvoke((System.Windows.Forms.MethodInvoker)delegate
+                    {
+                        targetFps = isTurboMode ? 1000 : 59.94;
+                        TargetFrameTime = 1000.0 / targetFps;
+                    });
                     double frameStartTime = _stopwatch.Elapsed.TotalMilliseconds;
 
                     // --- POLL PHYSICAL CONTROLLER ---
@@ -176,7 +236,7 @@ namespace Desktop
 
                         BeginInvoke((System.Windows.Forms.MethodInvoker)delegate
                         {
-                            this.Text = $"Parsons Master System 2026 - {_currentRomName} [FPS/FT: {FramesPerSecond:F0}/{FrameTime:F1}]";
+                            this.Text = $"{_romType} Parsons Master System 2026 - {_currentRomName} [FPS: {FramesPerSecond:F0}]";
                         });
                     }
 
@@ -201,6 +261,18 @@ namespace Desktop
             {
                 await _emulatorTask;
             }
+            _romType = Path.GetExtension(filePath);
+            if (_romType == ".sms")
+            {
+                _machine.VideoProcessor.IsGameGear = false;
+            }
+            else if (_romType == ".gg")
+            {
+                _machine.VideoProcessor.IsGameGear = true;
+            }
+            else
+                throw new Exception("Incorrect ROM Type!");
+            _romType = _machine.VideoProcessor.IsGameGear ? "GG" : "SMS";
 
             // 1. SAVE THE PREVIOUS GAME!
             SaveCurrentSram();
@@ -214,7 +286,7 @@ namespace Desktop
             // 4. Update the path tracking
             _currentRomPath = filePath;
             _currentRomName = Path.GetFileNameWithoutExtension(filePath);
-            this.Text = $"Parsons Master System - {_currentRomName}";
+            //this.Text = $"{_romType} Parsons Master System 2026 - {_currentRomName}";
 
             // 5. LOAD THE NEW SAVE DATA FROM THE EXE FOLDER!
             string savPath = GetSaveFilePath();
@@ -252,13 +324,11 @@ namespace Desktop
 
         private void PopulateIncludedRomsMenu()
         {
-            // The folder you used for Golden Axe Warrior
             string romsDirectory = @"C:\Parsons\Local Code Projects\ParsonsMasterSystem2026\Desktop\ROMS\";
 
             if (Directory.Exists(romsDirectory))
             {
                 string[] romFiles = Directory.GetFiles(romsDirectory, "*.sms");
-
                 foreach (string file in romFiles)
                 {
                     // Create a new dropdown item for each .sms file it finds
@@ -269,8 +339,20 @@ namespace Desktop
                     romMenuItem.Click += (sender, e) => LoadRomAndStart(file);
 
                     // Add it to the "Included" submenu (make sure the name matches your designer element!)
-                    includedToolStripMenuItem.DropDownItems.Add(romMenuItem);
+                    masterSystemToolStripMenuItem.DropDownItems.Add(romMenuItem);
                 }
+                romFiles = Directory.GetFiles(romsDirectory, "*.gg");
+                foreach (string file in romFiles)
+                {
+                    // Create a new dropdown item for each .gg file it finds
+                    string romName = Path.GetFileNameWithoutExtension(file);
+                    ToolStripMenuItem romMenuItem = new ToolStripMenuItem(romName);
+
+                    // When clicked, pass the file path to the helper method
+                    romMenuItem.Click += (sender, e) => LoadRomAndStart(file);
+                    gameGearToolStripMenuItem.DropDownItems.Add(romMenuItem);
+                }
+
             }
         }
 
@@ -279,7 +361,7 @@ namespace Desktop
             using (OpenFileDialog ofd = new OpenFileDialog())
             {
                 ofd.Title = "Select Master System ROM";
-                ofd.Filter = "SMS ROMs (*.sms)|*.sms|All Files (*.*)|*.*";
+                ofd.Filter = "SMS ROMs (*.sms)|*.sms|GG ROMs (*.gg)|*.gg|All Files (*.*)|*.*";
 
                 if (ofd.ShowDialog() == DialogResult.OK)
                 {
@@ -313,14 +395,10 @@ namespace Desktop
             _vramViewer.Show();
         }
 
-        private void includedToolStripMenuItem_Click(object sender, EventArgs e)
+        
-        {
-
-        }
-
         private void exitToolStripMenuItem_Click(object sender, EventArgs e)
         {
-           this.Close();
+            this.Close();
         }
 
         private void Form1_KeyDown(object sender, KeyEventArgs e)
@@ -400,5 +478,11 @@ namespace Desktop
             // 3. Resume
             StartEmulator();
         }
+
+        private void turboModeToolStripMenuItem_Click(object sender, EventArgs e)
+        {
+            turboModeToolStripMenuItem.Checked = !turboModeToolStripMenuItem.Checked;
+            isTurboMode = turboModeToolStripMenuItem.Checked ? true : false;
+        }
     }
 }

Desktop/VramViewerForm.cs

@@ -45,7 +45,6 @@ namespace Desktop
                 int tileX = (tile % 32) * 8;
                 int tileY = (tile / 32) * 8;
                 int tileAddress = tile * 32;
-
                 // Decode the 8x8 pixels
                 for (int y = 0; y < 8; y++)
                 {
@@ -57,19 +56,19 @@ namespace Desktop
                     for (int x = 0; x < 8; x++)
                     {
                         int shift = 7 - x;
-                        int colorIndex = ((bp0 >> shift) & 1) | (((bp1 >> shift) & 1) << 1) |
+                        int colourIndex = ((bp0 >> shift) & 1) | (((bp1 >> shift) & 1) << 1) |
                                          (((bp2 >> shift) & 1) << 2) | (((bp3 >> shift) & 1) << 3);
 
                         // Use the Sprite Palette (Offset 16) so characters and enemies are colored correctly
-                        byte smsColor = _vdp.CRAM[16 + colorIndex];
+                        int colour = _vdp.GetRgbColour(16, colourIndex);
-                        int r = (smsColor & 0x03) * 85;
+                        //int r = (smsColor & 0x03) * 85;
-                        int g = ((smsColor >> 2) & 0x03) * 85;
+                        //int g = ((smsColor >> 2) & 0x03) * 85;
-                        int b = ((smsColor >> 4) & 0x03) * 85;
+                        //int b = ((smsColor >> 4) & 0x03) * 85;
 
                         // Background color (Index 0) is technically transparent for sprites, so we render it as magenta
-                        if (colorIndex == 0) { r = 255; g = 0; b = 255; }
+                        //if (colourIndex == 0) { int r = 255; int g = 0; int b = 255; }
 
-                        _pixelData[((tileY + y) * 256) + (tileX + x)] = (255 << 24) | (r << 16) | (g << 8) | b;
+                        _pixelData[((tileY + y) * 256) + (tileX + x)] = colourIndex == 0 ? (255 << 24) | (255 << 16) | (0 << 8) | 255 : colour;
                     }
                 }
             }