Refactor instruction handlers to use single instruction per handler pattern

X86Disassembler/X86/Handlers/XorRegMemHandler.cs

@@ -0,0 +1,82 @@
+namespace X86Disassembler.X86.Handlers;
+
+/// <summary>
+/// Handler for XOR r32, r/m32 instruction (0x33)
+/// </summary>
+public class XorRegMemHandler : InstructionHandler
+{
+    // ModR/M decoder
+    private readonly ModRMDecoder _modRMDecoder;
+    
+    /// <summary>
+    /// Initializes a new instance of the XorRegMemHandler 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 XorRegMemHandler(byte[] codeBuffer, InstructionDecoder decoder, int length) 
+        : base(codeBuffer, decoder, length)
+    {
+        _modRMDecoder = new ModRMDecoder(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 == 0x33;
+    }
+    
+    /// <summary>
+    /// Decodes an XOR r32, r/m32 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)
+    {
+        // Set the mnemonic
+        instruction.Mnemonic = "xor";
+        
+        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);
+        
+        // Decode the source operand
+        string srcOperand = _modRMDecoder.DecodeModRM(mod, rm, false);
+        
+        // Get the destination register
+        string destReg = GetRegister32(reg);
+        
+        // Set the operands
+        instruction.Operands = $"{destReg}, {srcOperand}";
+        
+        return true;
+    }
+    
+    /// <summary>
+    /// Gets the 32-bit register name for the given register index
+    /// </summary>
+    /// <param name="reg">The register index</param>
+    /// <returns>The register name</returns>
+    private static string GetRegister32(byte reg)
+    {
+        string[] registerNames = { "eax", "ecx", "edx", "ebx", "esp", "ebp", "esi", "edi" };
+        return registerNames[reg & 0x07];
+    }
+}