Added support for MOV r/m8, imm8 (0xC6) and ADD r/m32, r32 (0x01) instructions with tests

X86Disassembler/X86/Handlers/Add/AddRm32R32Handler.cs

@@ -0,0 +1,73 @@
+namespace X86Disassembler.X86.Handlers.Add;
+
+/// <summary>
+/// Handler for ADD r/m32, r32 instruction (0x01)
+/// </summary>
+public class AddRm32R32Handler : InstructionHandler
+{
+    /// <summary>
+    /// Initializes a new instance of the AddRm32R32Handler class
+    /// </summary>
+    /// <param name="codeBuffer">The buffer containing the code to decode</param>
+    /// <param name="decoder">The instruction decoder that owns this handler</param>
+    /// <param name="length">The length of the buffer</param>
+    public AddRm32R32Handler(byte[] codeBuffer, InstructionDecoder decoder, int length)
+        : base(codeBuffer, decoder, length)
+    {
+    }
+
+    /// <summary>
+    /// Checks if this handler can decode the given opcode
+    /// </summary>
+    /// <param name="opcode">The opcode to check</param>
+    /// <returns>True if this handler can decode the opcode</returns>
+    public override bool CanHandle(byte opcode)
+    {
+        return opcode == 0x01;
+    }
+
+    /// <summary>
+    /// Decodes an ADD r/m32, r32 instruction
+    /// </summary>
+    /// <param name="opcode">The opcode of the instruction</param>
+    /// <param name="instruction">The instruction object to populate</param>
+    /// <returns>True if the instruction was successfully decoded</returns>
+    public override bool Decode(byte opcode, Instruction instruction)
+    {
+        int position = Decoder.GetPosition();
+
+        if (position >= Length)
+        {
+            return false;
+        }
+
+        // Read the ModR/M byte
+        byte modRM = CodeBuffer[position++];
+        Decoder.SetPosition(position);
+
+        // Extract the fields from the ModR/M byte
+        byte mod = (byte)((modRM & 0xC0) >> 6);
+        byte reg = (byte)((modRM & 0x38) >> 3);
+        byte rm = (byte)(modRM & 0x07);
+
+        // Set the mnemonic
+        instruction.Mnemonic = "add";
+
+        // Get the register name
+        string regName = GetRegister32(reg);
+
+        // For memory operands, set the operand
+        if (mod != 3) // Memory operand
+        {
+            string operand = ModRMDecoder.DecodeModRM(mod, rm, false);
+            instruction.Operands = $"{operand}, {regName}";
+        }
+        else // Register operand
+        {
+            string rmName = GetRegister32(rm);
+            instruction.Operands = $"{rmName}, {regName}";
+        }
+
+        return true;
+    }
+}

X86Disassembler/X86/Handlers/InstructionHandlerFactory.cs

@@ -266,6 +266,7 @@ public class InstructionHandlerFactory
     {
         // Add Add handlers
         _handlers.Add(new AddR32Rm32Handler(_codeBuffer, _decoder, _length));
+        _handlers.Add(new AddRm32R32Handler(_codeBuffer, _decoder, _length));
     }
     
     /// <summary>
@@ -290,6 +291,7 @@ public class InstructionHandlerFactory
         _handlers.Add(new MovEaxMoffsHandler(_codeBuffer, _decoder, _length));
         _handlers.Add(new MovMoffsEaxHandler(_codeBuffer, _decoder, _length));
         _handlers.Add(new MovRm32Imm32Handler(_codeBuffer, _decoder, _length));
+        _handlers.Add(new MovRm8Imm8Handler(_codeBuffer, _decoder, _length));
         
         // Add PUSH handlers
         _handlers.Add(new PushRegHandler(_codeBuffer, _decoder, _length));

X86Disassembler/X86/Handlers/Mov/MovRm8Imm8Handler.cs

@@ -0,0 +1,125 @@
+namespace X86Disassembler.X86.Handlers.Mov;
+
+/// <summary>
+/// Handler for MOV r/m8, imm8 instruction (0xC6)
+/// </summary>
+public class MovRm8Imm8Handler : InstructionHandler
+{
+    /// <summary>
+    /// Initializes a new instance of the MovRm8Imm8Handler class
+    /// </summary>
+    /// <param name="codeBuffer">The buffer containing the code to decode</param>
+    /// <param name="decoder">The instruction decoder that owns this handler</param>
+    /// <param name="length">The length of the buffer</param>
+    public MovRm8Imm8Handler(byte[] codeBuffer, InstructionDecoder decoder, int length)
+        : base(codeBuffer, decoder, length)
+    {
+    }
+
+    /// <summary>
+    /// Checks if this handler can decode the given opcode
+    /// </summary>
+    /// <param name="opcode">The opcode to check</param>
+    /// <returns>True if this handler can decode the opcode</returns>
+    public override bool CanHandle(byte opcode)
+    {
+        return opcode == 0xC6;
+    }
+
+    /// <summary>
+    /// Decodes a MOV r/m8, imm8 instruction
+    /// </summary>
+    /// <param name="opcode">The opcode of the instruction</param>
+    /// <param name="instruction">The instruction object to populate</param>
+    /// <returns>True if the instruction was successfully decoded</returns>
+    public override bool Decode(byte opcode, Instruction instruction)
+    {
+        int position = Decoder.GetPosition();
+
+        if (position >= Length)
+        {
+            return false;
+        }
+
+        // Read the ModR/M byte
+        byte modRM = CodeBuffer[position++];
+        
+        // Extract the fields from the ModR/M byte
+        byte mod = (byte)((modRM & 0xC0) >> 6);
+        byte reg = (byte)((modRM & 0x38) >> 3);
+        byte rm = (byte)(modRM & 0x07);
+        
+        // MOV r/m8, imm8 only uses reg=0
+        if (reg != 0)
+        {
+            return false;
+        }
+        
+        // Process SIB and displacement bytes if needed
+        if (mod != 3 && rm == 4) // SIB byte present
+        {
+            if (position >= Length)
+            {
+                return false;
+            }
+            position++; // Skip SIB byte
+        }
+        
+        // Handle displacement
+        if ((mod == 1 && position >= Length) || (mod == 2 && position + 3 >= Length))
+        {
+            return false;
+        }
+        
+        if (mod == 1) // 8-bit displacement
+        {
+            position++;
+        }
+        else if (mod == 2) // 32-bit displacement
+        {
+            position += 4;
+        }
+        
+        // Read the immediate byte
+        if (position >= Length)
+        {
+            return false;
+        }
+        
+        byte imm8 = CodeBuffer[position++];
+        Decoder.SetPosition(position);
+
+        // Set the mnemonic
+        instruction.Mnemonic = "mov";
+
+        // Get the operand string
+        string operand;
+        if (mod != 3) // Memory operand
+        {
+            string memOperand = ModRMDecoder.DecodeModRM(mod, rm, true);
+            
+            // Replace the size prefix with "byte ptr"
+            if (memOperand.StartsWith("qword ptr "))
+            {
+                operand = memOperand.Replace("qword ptr ", "byte ptr ");
+            }
+            else if (memOperand.StartsWith("dword ptr "))
+            {
+                operand = memOperand.Replace("dword ptr ", "byte ptr ");
+            }
+            else
+            {
+                operand = $"byte ptr {memOperand}";
+            }
+        }
+        else // Register operand
+        {
+            operand = GetRegister8(rm);
+        }
+
+        // Set the operands
+        instruction.Operands = $"{operand}, 0x{imm8:X2}";
+
+        return true;
+    }
+}

X86DisassemblerTests/AddRm32R32Tests.cs

@@ -0,0 +1,49 @@
+namespace X86DisassemblerTests;
+
+using System;
+using Xunit;
+using X86Disassembler.X86;
+
+/// <summary>
+/// Tests for ADD r/m32, r32 instruction (0x01)
+/// </summary>
+public class AddRm32R32Tests
+{
+    /// <summary>
+    /// Tests the ADD r32, r32 instruction (0x01) with register operand
+    /// </summary>
+    [Fact]
+    public void TestAddR32R32()
+    {
+        // Arrange
+        byte[] code = { 0x01, 0xC1 }; // ADD ECX, EAX
+        
+        // Act
+        Disassembler disassembler = new Disassembler(code, 0x1000);
+        var instructions = disassembler.Disassemble();
+        
+        // Assert
+        Assert.Single(instructions);
+        Assert.Equal("add", instructions[0].Mnemonic);
+        Assert.Equal("ecx, eax", instructions[0].Operands);
+    }
+    
+    /// <summary>
+    /// Tests the ADD m32, r32 instruction (0x01) with memory operand
+    /// </summary>
+    [Fact]
+    public void TestAddM32R32()
+    {
+        // Arrange
+        byte[] code = { 0x01, 0x01 }; // ADD DWORD PTR [ECX], EAX
+        
+        // Act
+        Disassembler disassembler = new Disassembler(code, 0x1000);
+        var instructions = disassembler.Disassemble();
+        
+        // Assert
+        Assert.Single(instructions);
+        Assert.Equal("add", instructions[0].Mnemonic);
+        Assert.Equal("dword ptr [ecx], eax", instructions[0].Operands);
+    }
+}

X86DisassemblerTests/MovRm8Imm8Tests.cs

@@ -0,0 +1,49 @@
+namespace X86DisassemblerTests;
+
+using System;
+using Xunit;
+using X86Disassembler.X86;
+
+/// <summary>
+/// Tests for MOV r/m8, imm8 instruction (0xC6)
+/// </summary>
+public class MovRm8Imm8Tests
+{
+    /// <summary>
+    /// Tests the MOV r8, imm8 instruction (0xC6) with register operand
+    /// </summary>
+    [Fact]
+    public void TestMovR8Imm8()
+    {
+        // Arrange
+        byte[] code = { 0xC6, 0xC0, 0x42 }; // MOV AL, 0x42
+        
+        // Act
+        Disassembler disassembler = new Disassembler(code, 0x1000);
+        var instructions = disassembler.Disassemble();
+        
+        // Assert
+        Assert.Single(instructions);
+        Assert.Equal("mov", instructions[0].Mnemonic);
+        Assert.Equal("al, 0x42", instructions[0].Operands);
+    }
+    
+    /// <summary>
+    /// Tests the MOV m8, imm8 instruction (0xC6) with memory operand
+    /// </summary>
+    [Fact]
+    public void TestMovM8Imm8()
+    {
+        // Arrange
+        byte[] code = { 0xC6, 0x01, 0x01 }; // MOV BYTE PTR [ECX], 0x01
+        
+        // Act
+        Disassembler disassembler = new Disassembler(code, 0x1000);
+        var instructions = disassembler.Disassemble();
+        
+        // Assert
+        Assert.Single(instructions);
+        Assert.Equal("mov", instructions[0].Mnemonic);
+        Assert.Equal("byte ptr [ecx], 0x01", instructions[0].Operands);
+    }
+}