Initial commit

7 files changed, 757 insertions, 0 deletions

diff --git a/Chip/Bus.cs b/Chip/Bus.cs
new file mode 100644
index 0000000..e8cf5ad
--- /dev/null
+++ b/Chip/Bus.cs
@@ -0,0 +1,55 @@
+namespace Q1Emu.Chip;
+
+using System.Collections.Generic;
+using System.Linq;
+
+public class Bus : BusDevice
+{
+    public List<BusDevice> Devices;
+
+    public Bus(u16 addressableStart, u16 addressableEnd) : base(addressableStart, addressableEnd)
+    {
+        this.Devices = [];
+    }
+    private BusDevice? GetDevice(u16 address)
+    {
+        BusDevice? device = this.Devices.FirstOrDefault(x => address >= x.AddressableStart && address < x.AddressableEnd);
+        return device;
+    }
+
+    public override u8 Read(u16 address)
+    {
+        BusDevice? device = GetDevice(address);
+        if (device == null)
+            return 0;
+
+        return device.Read(address);
+    }
+
+    public override void Write(u16 address, u8 value)
+    {
+        BusDevice? device = GetDevice(address);
+        if (device == null)
+            return;
+
+        device.Write(address, value);
+    }
+
+    public override ref8 ReadSeq(u16 address, u16 length)
+    {
+        BusDevice? device = this.GetDevice(address);
+        if (device == null)
+            return [];
+
+        return device.ReadSeq(address, length);
+    }
+
+    public override void WriteSeq(u16 address, u16 length, ref8 value)
+    {
+        BusDevice? device = this.GetDevice(address);
+        if (device == null)
+            return;
+
+        device.WriteSeq(address, length, value);
+    }
+}
\ No newline at end of file
diff --git a/Chip/BusDevice.cs b/Chip/BusDevice.cs
new file mode 100644
index 0000000..e1f559c
--- /dev/null
+++ b/Chip/BusDevice.cs
@@ -0,0 +1,50 @@
+namespace Q1Emu.Chip;
+
+using System.Runtime.CompilerServices;
+
+public abstract class BusDevice
+{
+    public BusDevice(u16 addressableStart, u16 addressableEnd)
+    {
+        this.AddressableStart = addressableStart;
+        this.AddressableEnd   = addressableEnd;
+    }
+    
+    public Bus Bus { get; set; }
+    public abstract u8 Read(u16 address);
+    public abstract void Write(u16 address, u8 value);
+    
+    public abstract ref8 ReadSeq(u16 address, u16 length);
+    public abstract void WriteSeq(u16 address, u16 length, ref8 value);
+    
+    public u16 ReadWord(u16 address)
+    {
+        ref8 data = this.ReadSeq(address, 2);
+        u16 value = Make.u16(data);
+        return value;
+    }
+    
+    public void WriteWord(u16 address, u16 value)
+    {
+        ref8 data = Make.ref8(value);
+        this.WriteSeq(address, 2, data);
+    }
+
+    public virtual void Clock() { }
+    public virtual void Reset() { }
+    
+    public void AttachToBus(Bus bus)
+    {
+        this.Bus = bus;
+        bus.Devices.Add(this);
+    }
+    
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected u16 GetRelativeAddress(u16 address)
+    {
+        return (u16) (address - this.AddressableStart);
+    }
+
+    public u16 AddressableStart { get; }
+    public u16 AddressableEnd   { get; }
+}
\ No newline at end of file
diff --git a/Chip/DisplayDevice.cs b/Chip/DisplayDevice.cs
new file mode 100644
index 0000000..ea34cfb
--- /dev/null
+++ b/Chip/DisplayDevice.cs
@@ -0,0 +1,76 @@
+namespace Q1Emu.Chip;
+
+using System;
+using System.Collections.Generic;
+using Microsoft.Xna.Framework;
+using Microsoft.Xna.Framework.Graphics;
+
+public class DisplayDevice : RamDevice
+{
+    public           Texture2D? OutputTexture;
+    private readonly u16        _paletteSize;
+    private readonly u16        _displayWidth;
+    private readonly u16        _displayHeight;
+
+    public DisplayDevice(u16 paletteSize, u16 displayWidth, u16 displayHeight, u16 addressableStart)
+        : base(addressableStart, DisplayDevice.DetermineSize(paletteSize, displayWidth, displayHeight))
+    {
+        this._paletteSize   = paletteSize;
+        this._displayWidth  = displayWidth;
+        this._displayHeight = displayHeight;
+    }
+
+    private static u16 DetermineSize(u16 paletteSize, u16 displayWidth, u16 displayHeight)
+    {
+        return (u16) ((paletteSize * 3) + (displayWidth * displayHeight));
+    }
+
+    public override void Clock()
+    {
+        Color[] palette = this.ReadPalette();
+        ref8 pixelData = this.ReadSeq((u16) (this.AddressableStart + this._paletteSize * 3), (u16) (this._displayWidth * this._displayHeight));
+
+        Color[] textureData = new Color[this._displayWidth * this._displayHeight];
+        for (u16 i = 0; i < textureData.Length; i++)
+        {
+            u8 pixelValue = pixelData[i];
+            textureData[i] = palette[pixelValue];
+        }
+
+        if (this.OutputTexture != null)
+            this.OutputTexture.SetData(textureData);
+    }
+
+    private Color[] ReadPalette()
+    {
+        ref8 paletteData = this.ReadSeq(this.AddressableStart, (u16) (this._paletteSize * 3));
+        Color[] colors = new Color[this._paletteSize + 1];
+        colors[0] = Color.Transparent;
+
+        for (u16 i = 0; i < this._paletteSize; i++)
+        {
+            u16 offset = (u16) (i * 3);
+            byte r = paletteData[offset];
+            byte g = paletteData[offset + 1];
+            byte b = paletteData[offset + 2];
+            colors[(u16) (i             + 1)] = new Color(r, g, b);
+        }
+
+        return colors;
+    }
+
+    public void SetPalette(Color[] palette)
+    {
+        if (palette.Length != this._paletteSize)
+            throw new ArgumentException($"Palette must have {this._paletteSize} colors.");
+
+        ref8 paletteData = this.ReadSeq(this.AddressableStart, (u16) (this._paletteSize * 3));
+        for (u16 i = 0; i < this._paletteSize; i++)
+        {
+            u16 offset = (u16) (i * 3);
+            paletteData[offset]     = palette[i].R;
+            paletteData[offset + 1] = palette[i].G;
+            paletteData[offset + 2] = palette[i].B;
+        }
+    }
+}
\ No newline at end of file
diff --git a/Chip/Q1Cpu.cs b/Chip/Q1Cpu.cs
new file mode 100644
index 0000000..1124578
--- /dev/null
+++ b/Chip/Q1Cpu.cs
@@ -0,0 +1,152 @@
+using System;
+
+namespace Q1Emu.Chip;
+
+using System.Collections.Generic;
+
+public partial class Q1Cpu
+{
+    public const u16 StackStart  = 0x30;
+    public const u16 StackLength = 16 * 2; // 16 16-bit values
+
+    public Random Random;
+
+    public u16 AX = 0; // Accumulator register
+    public u16 DX = 0; // Data register
+    public u16 LX = 0; // Logical register
+
+    public u16 SP { get; set; } // Stack pointer
+    public u16 PC { get; set; } // Program counter
+
+    public u16[] V      { get; set; } // Variable registers (64 total)
+    public u16   I      { get; set; } // Index register
+    public u16   Cycles { get; set; } // Number of cycles
+
+    public Bus Bus { get; set; }
+
+    public Q1Cpu()
+    {
+        this.LoadInstructionLookup();
+
+        this.Reset();
+    }
+
+    public void Reset()
+    {
+        this.V = new u16[16];
+
+        this.SP = StackStart;
+
+        this.I = 0;
+    }
+
+    public void Clock()
+    {
+        u16 instruction = this.FetchInstruction(out u8 op, out u8 m1, out u8 m2, out _);
+
+        bool ex = m2 > 0;
+        switch (m1, ex)
+        {
+            case (0x00, false):
+                this.InstructionLookup[op].Item1(); // Implicit
+                break;
+            case (> 0x00, false):
+                this.InstructionLookup[op].Item2(m1); // Simple addressing mode
+                break;
+            case (0x00, true):
+                this.InstructionLookup[op].Item3(); // Extended implicit
+                break;
+            case (> 0x00, true):
+                this.InstructionLookup[op].Item4(m1, m2); // Extended addressing mode
+                break;
+        }
+
+        this.Cycles++;
+    }
+    public u16 FetchInstruction(out u8 op, out u8 m1, out u8 m2, out u8 length)
+    {
+        u16 instruction = this.Bus.ReadWord(this.PC);
+        this.PC += 2;
+
+        op = (u8) ((instruction >> 8) & 0xFF); // 256 opcodes
+        m1 = (u8) ((instruction >> 4) & 0x0F); // 16 modes
+        m2 = (u8) (instruction        & 0x0F); // 16 modes
+
+        length = (u8) (this.AddressingModeLength(m1) + this.AddressingModeLength(m2));
+        return instruction;
+    }
+
+    private void PushStack(u16 value)
+    {
+        if (this.SP + 2 >= StackStart + StackLength)
+            throw new InvalidOperationException("Stack overflow");
+
+        this.Bus.WriteSeq(this.SP, 2, Make.ref8(value));
+        this.SP += 2;
+    }
+
+    private u16 PopStack()
+    {
+        if (this.SP - 2 < StackStart)
+            throw new InvalidOperationException("Stack underflow");
+
+        this.SP -= 2;
+        return Make.u16(this.Bus.ReadSeq(this.SP, 2));
+    }
+
+    private u16 FetchRegister(u8 regIndex)
+    {
+        return regIndex switch
+        {
+            <= 0x3F => this.V[regIndex],
+
+            0x40 => this.AX,
+            0x41 => (u16) (this.AX >> 8),   // High byte of AX
+            0x42 => (u16) (this.AX & 0xFF), // Low byte of AX
+
+            0x43 => this.DX,
+            0x44 => (u16) (this.DX >> 8),   // High byte of DX
+            0x45 => (u16) (this.DX & 0xFF), // Low byte of DX
+
+            0x46 => this.LX,
+            0x50 => this.PC,
+            0x51 => this.SP,
+
+            _ => throw new InvalidOperationException($"Unknown register index: {regIndex:X2}"),
+        };
+    }
+
+    private void StoreRegister(u8 regIndex, u16 value)
+    {
+        switch (regIndex)
+        {
+            case <= 0x3F:
+                this.V[regIndex] = value;
+                break;
+
+            case 0x40:
+                this.AX = value; break;
+            case 0x41:
+                this.AX = (u16) ((this.AX & 0x00FF) | (value << 8)); break; // Set high byte
+            case 0x42:
+                this.AX = (u16) ((this.AX & 0xFF00) | (value & 0x00FF)); break; // Set low byte
+
+            case 0x43:
+                this.DX = value; break;
+            case 0x44:
+                this.DX = (u16) ((this.DX & 0x00FF) | (value << 8)); break; // Set high byte
+            case 0x45:
+                this.DX = (u16) ((this.DX & 0xFF00) | (value & 0x00FF)); break; // Set low byte
+
+            case 0x46:
+                this.LX = value; break;
+            case 0x50:
+                this.PC = value; break;
+            case 0x51:
+                this.SP = value; break;
+
+            default:
+                throw new InvalidOperationException($"Unknown register index: {regIndex:X2}");
+        }
+    }
+}
\ No newline at end of file
diff --git a/Chip/Q1CpuAddressingModes.cs b/Chip/Q1CpuAddressingModes.cs
new file mode 100644
index 0000000..0d664f7
--- /dev/null
+++ b/Chip/Q1CpuAddressingModes.cs
@@ -0,0 +1,150 @@
+namespace Q1Emu.Chip;
+
+using System;
+using System.Collections.Generic;
+
+public partial class Q1Cpu
+{
+    public u16 FetchData(u8 mode)
+    {
+        return mode switch
+        {
+            0x0 => this.AddressingMode_Implicit(),
+            0x1 => this.AddressingMode_Immediate(),
+            0x2 => this.AddressingMode_Direct(),
+            0x3 => this.AddressingMode_Indirect(),
+            0x4 => this.AddressingMode_Relative(),
+            0x5 => this.AddressingMode_Register(),
+            0x6 => this.AddressingMode_RegisterIndirect(),
+            0x7 => this.AddressingMode_RegisterIndirectOffset(),
+            _   => throw new InvalidOperationException($"Unknown addressing mode: {mode:X2}"),
+        };
+    }
+    
+    public void StoreData(u8 mode, u16 value)
+    {
+        Console.WriteLine($"StoreData: mode={mode:X8}, value={value:X16}");
+        if (mode != 0x05)
+        {
+            u16 address = this.FetchData(mode);
+            Console.WriteLine($"StoreData: address={address:X16}");
+            this.Bus.WriteWord(address, value);
+        }
+        else
+        {
+            u8 regIndex = this.Bus.Read(this.PC);
+            this.PC += 1;
+
+            this.StoreRegister(regIndex, value);
+        }
+    }
+    
+    public void TransformData(u8 mode, Func<u16, u16> transform)
+    {
+        if (mode != 0x05)
+        {
+            u16 address = this.FetchData(mode);
+            u16 value = this.Bus.ReadWord(address);
+            u16 transformedValue = transform(value);
+            this.Bus.WriteWord(address, transformedValue);
+        }
+        else
+        {
+            u8 regIndex = this.Bus.Read(this.PC);
+            this.PC += 1;
+
+            u16 value = this.FetchRegister(regIndex);
+            u16 transformedValue = transform(value);
+            this.StoreRegister(regIndex, transformedValue);
+        }
+    }
+
+    public u8 AddressingModeLength(u8 mode)
+    {
+        return mode switch
+        {
+            0x0 => 0, // Implicit
+            0x1 => 2, // Immediate
+            0x2 => 2, // Direct
+            0x3 => 2, // Indirect
+            0x4 => 2, // Relative
+            0x5 => 1, // Register
+            0x6 => 1, // Register indirect
+            0x7 => 3, // Register indirect with offset
+            _   => throw new InvalidOperationException($"Unknown addressing mode: {mode:X2}"),
+        };
+    }
+    
+    public u16 AddressingMode_Implicit()
+    {
+        return 0;
+    }
+
+
+    public u16 AddressingMode_Immediate()
+    {
+        u16 value = this.Bus.ReadWord(this.PC);
+        this.PC += 2;
+
+        return value;
+    }
+
+    public u16 AddressingMode_Direct()
+    {
+        u16 address = this.Bus.ReadWord(this.PC);
+        this.PC += 2;
+
+        u16 value = this.Bus.ReadWord(address);
+        return value;
+    }
+
+    public u16 AddressingMode_Indirect()
+    {
+        u16 address = this.Bus.ReadWord(this.PC);
+        this.PC += 2;
+
+        u16 indirectAddress = this.Bus.ReadWord(address);
+        u16 value = this.Bus.ReadWord(indirectAddress);
+        return value;
+    }
+
+    public u16 AddressingMode_Relative()
+    {
+        u16 offset = this.Bus.ReadWord(this.PC);
+        this.PC += 2;
+
+        u16 address = (u16) (this.PC + offset);
+        return address;
+    }
+
+    public u16 AddressingMode_Register()
+    {
+        u8 regIndex = this.Bus.Read(this.PC);
+        this.PC += 1;
+
+        return this.FetchRegister(regIndex);
+    }
+
+    public u16 AddressingMode_RegisterIndirect()
+    {
+        u8 regIndex = this.Bus.Read(this.PC);
+        this.PC += 1;
+
+        u16 address = this.FetchRegister(regIndex);
+        u16 value = this.Bus.ReadWord(address);
+        return value;
+    }
+
+    public u16 AddressingMode_RegisterIndirectOffset()
+    {
+        u8 regIndex = this.Bus.Read(this.PC);
+        this.PC += 1;
+
+        u16 offset = this.Bus.ReadWord(this.PC);
+        this.PC += 2;
+
+        u16 address = (u16) (this.FetchRegister(regIndex) + offset);
+        u16 value = this.Bus.ReadWord(address);
+        return value;
+    }
+}
\ No newline at end of file
diff --git a/Chip/Q1CpuInstructions.cs b/Chip/Q1CpuInstructions.cs
new file mode 100644
index 0000000..8b79a1d
--- /dev/null
+++ b/Chip/Q1CpuInstructions.cs
@@ -0,0 +1,225 @@
+namespace Q1Emu.Chip;
+
+using System;
+using System.Collections.Generic;
+
+public partial class Q1Cpu
+{
+    public Dictionary<u8, (Action, Action<u8>, Action, Action<u8, u8>)> InstructionLookup;
+    private void LoadInstructionLookup()
+    {
+        this.InstructionLookup = new Dictionary<u8, (Action, Action<u8>, Action, Action<u8, u8>)>
+        {
+            { 0x00, (this.Instruction_NOP, this.Instruction_JMP, this.Instruction_HALT, this.Instruction_MOV) },
+            { 0x01, (this.Instruction_RET, this.Instruction_CALL, this.Instruction_SUS, this.Instruction_CMP) },
+            { 0x02, (this.Instruction_BR, this.Instruction_BZ, this.Instruction_BZ_LX, this.Instruction_LT) },
+            { 0x03, (this.Instruction_NOP, this.Instruction_NOP, this.Instruction_NOP, this.Instruction_GT) },
+
+            { 0x04, (this.Instruction_NOT_LX, this.Instruction_NOT, this.Instruction_NOP, this.Instruction_AND) },
+            { 0x05, (this.Instruction_INV_DX, this.Instruction_INV, this.Instruction_NOP, this.Instruction_OR) },
+            { 0x06, (this.Instruction_SHL_DX, this.Instruction_SHL, this.Instruction_NOP, this.Instruction_XOR) },
+            { 0x07, (this.Instruction_SHR_DX, this.Instruction_SHR, this.Instruction_NOP, this.Instruction_NOP) },
+
+            { 0x08, (this.Instruction_INC_AX, this.Instruction_INC, this.Instruction_NOP, this.Instruction_ADD) },
+            { 0x09, (this.Instruction_DEC_AX, this.Instruction_DEC, this.Instruction_NOP, this.Instruction_SUB) },
+            { 0x0A, (this.Instruction_NOP, this.Instruction_NOP, this.Instruction_NOP, this.Instruction_DIV) },
+            { 0x0B, (this.Instruction_NOP, this.Instruction_NOP, this.Instruction_NOP, this.Instruction_MUL) },
+            { 0x0C, (this.Instruction_NOP, this.Instruction_NOP, this.Instruction_NOP, this.Instruction_MOD) },
+        };
+    }
+    private void Instruction_ADD(u8 m1, u8 m2)
+    {
+        u16 v1 = this.FetchData(m1);
+        u16 v2 = this.FetchData(m2);
+        
+        u16 result = (u16) (v1 + v2);
+        this.AX = result;
+    }
+    private void Instruction_SUB(u8 m1, u8 m2)
+    {
+        u16 v1 = this.FetchData(m1);
+        u16 v2 = this.FetchData(m2);
+        
+        u16 result = (u16)(v1 - v2);
+        this.AX = result;
+    }
+    private void Instruction_MUL(u8 m1, u8 m2)
+    {
+        u16 v1 = this.FetchData(m1);
+        u16 v2 = this.FetchData(m2);
+        
+        u16 result = (u16) (v1 * v2);
+        this.AX = result;
+    }
+    private void Instruction_DIV(u8 m1, u8 m2)
+    {
+        u16 v1 = this.FetchData(m1);
+        u16 v2 = this.FetchData(m2);
+        
+        if (v2 == 0)
+            throw new DivideByZeroException("Cannot perform division by zero.");
+        u16 result = (u16)(v1 / v2);
+        this.AX = result;
+    }
+    private void Instruction_MOD(u8 m1, u8 m2)
+    {
+        u16 v1 = this.FetchData(m1);
+        u16 v2 = this.FetchData(m2);
+        
+        if (v2 == 0)
+            throw new DivideByZeroException("Cannot perform modulo operation with divisor zero.");
+        u16 result = (u16)(v1 % v2);
+        this.AX = result;
+    }
+    private void Instruction_INC(u8 obj)
+    {
+        this.TransformData(obj, value => (u16)(value + 1));
+    }
+    private void Instruction_DEC(u8 obj)
+    {
+        this.TransformData(obj, value => (u16)(value - 1));
+    }
+    private void Instruction_INC_AX()
+    {
+        this.AX = (u16)(this.AX + 1);
+    }
+    private void Instruction_DEC_AX()
+    {
+        this.AX = (u16)(this.AX - 1);
+    }
+    private void Instruction_SHL(u8 obj)
+    {
+        this.TransformData(obj, value => (u16)(value << 1));
+    }
+    private void Instruction_SHR(u8 obj)
+    {
+        this.TransformData(obj, value => (u16)(value >> 1));
+    }
+    private void Instruction_SHL_DX()
+    {
+        this.DX = (u16)(this.DX << 1);
+    }
+    private void Instruction_SHR_DX()
+    {
+        this.DX = (u16)(this.DX >> 1);
+    }
+    private void Instruction_XOR(u8 m1, u8 m2)
+    {
+        u16 v1 = this.FetchData(m1);
+        u16 v2 = this.FetchData(m2);
+        
+        u16 result = (u16)(v1 ^ v2);
+        this.DX = result;
+    }
+    private void Instruction_OR(u8 m1, u8 m2)
+    {
+        u16 v1 = this.FetchData(m1);
+        u16 v2 = this.FetchData(m2);
+        
+        u16 result = (u16)(v1 | v2);
+        this.DX = result;
+    }
+    private void Instruction_INV(u8 obj)
+    {
+        u16 value = this.FetchData(obj);
+        u16 result = (u16)~value;
+        this.DX = result;
+    }
+    private void Instruction_INV_DX()
+    {
+        this.DX = (u16)~this.DX;
+    }
+    private void Instruction_AND(u8 m1, u8 m2)
+    {
+        u16 v1 = this.FetchData(m1);
+        u16 v2 = this.FetchData(m2);
+        
+        u16 result = (u16)(v1 & v2);
+        this.DX = result;
+    }
+    private void Instruction_NOT(u8 obj)
+    {
+        u16 value = this.FetchData(obj);
+        u16 result = value == 0 ? (u16)1 : (u16)0;
+        this.LX = result;
+    }
+    private void Instruction_NOT_LX()
+    {
+        this.LX = this.LX == 0 ? (u16)1 : (u16)0;
+    }
+    private void Instruction_GT(u8 m1, u8 m2)
+    {
+        u16 v1 = this.FetchData(m1);
+        u16 v2 = this.FetchData(m2);
+        
+        this.LX = (u16)(v1 > v2 ? 1 : 0);
+    }
+    private void Instruction_LT(u8 m1, u8 m2)
+    {
+        u16 v1 = this.FetchData(m1);
+        u16 v2 = this.FetchData(m2);
+        
+        this.LX = (u16)(v1 < v2 ? 1 : 0);
+    }
+    
+    private void Instruction_BR()
+    {
+        this.FetchInstruction(out _, out _, out _, out u8 length);
+        this.PC += length;
+    }
+    private void Instruction_BZ_LX()
+    {
+        if (this.LX == 0)
+            this.Instruction_BR();
+    }
+    private void Instruction_BZ(u8 obj)
+    {
+        u16 value = this.FetchData(obj);
+        if (value == 0)
+            this.Instruction_BR();
+    }
+    private void Instruction_CMP(u8 m1, u8 m2)
+    {
+        u16 v1 = this.FetchData(m1);
+        u16 v2 = this.FetchData(m2);
+        
+        // Set LX based on comparison
+        this.LX = (u16)(v1 == v2 ? 1 : 0);
+    }
+    private void Instruction_MOV(u8 m1, u8 m2)
+    {
+        u16 value = this.FetchData(m1);
+        this.StoreData(m2, value);
+    }
+
+    public void Instruction_NOP() { }
+    public void Instruction_NOP(u8 m1) { }
+    public void Instruction_NOP(u8 m1, u8 m2) { }
+
+    public void Instruction_JMP(u8 m1)
+    {
+        this.PC = this.FetchData(m1);
+    }
+
+    public void Instruction_RET()
+    {
+        this.PC = this.PopStack();
+    }
+
+    public void Instruction_CALL(u8 m1)
+    {
+        u16 address = this.FetchData(m1);
+        this.PushStack(this.PC);
+        this.PC = address;
+    }
+
+    public void Instruction_HALT()
+    {
+        throw new NotImplementedException("Halt instruction not implemented yet.");
+    }
+
+    public void Instruction_SUS()
+    {
+        this.PC -= 2;
+    }
+}
\ No newline at end of file
diff --git a/Chip/RamDevice.cs b/Chip/RamDevice.cs
new file mode 100644
index 0000000..6811d22
--- /dev/null
+++ b/Chip/RamDevice.cs
@@ -0,0 +1,49 @@
+namespace Q1Emu.Chip;
+
+using System;
+using System.Runtime.CompilerServices;
+
+public class RamDevice : BusDevice
+{
+    public u8[] Memory;
+
+    public RamDevice(u16 start, u16 size) : base(start, (u16) (start + size))
+    {
+        this.Memory           = new u8[size];
+    }
+    
+    public override void Reset()
+    {
+        this.Memory = new u8[this.AddressableEnd - this.AddressableStart];
+    }
+    
+    public override void Clock()
+    {
+        // No clocking needed for RAM
+    }
+
+    public override u8 Read(u16 address)
+    {
+        u16 relativeAddress = this.GetRelativeAddress(address);
+        return this.Memory[relativeAddress];
+    }
+
+    public override void Write(u16 address, u8 value)
+    {
+        u16 relativeAddress = this.GetRelativeAddress(address);
+        this.Memory[relativeAddress] = value;
+    }
+
+    public override ref8 ReadSeq(u16 address, u16 length)
+    {
+        u16 relativeAddress = this.GetRelativeAddress(address);
+        // Console.WriteLine($"{address:X4} {relativeAddress:X4} {length:X4}");
+        return new ref8(this.Memory, relativeAddress, length);
+    }
+    
+    public override void WriteSeq(u16 address, u16 length, ref8 value)
+    {
+        ref8 destination = this.ReadSeq(address, length);
+        value.CopyTo(destination);
+    }
+}
\ No newline at end of file