Added comprehensive test coverage for arithmetic and logical instructions. Implemented AND instruction handlers and added tests for ADC, SBB, and arithmetic unary operations.

X86Disassembler/X86/Handlers/And/AndMemRegHandler.cs

@@ -0,0 +1,66 @@
+namespace X86Disassembler.X86.Handlers.And;
+
+/// <summary>
+/// Handler for AND r/m32, r32 instruction (0x21)
+/// </summary>
+public class AndMemRegHandler : InstructionHandler
+{
+    /// <summary>
+    /// Initializes a new instance of the AndMemRegHandler 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 AndMemRegHandler(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 == 0x21;
+    }
+    
+    /// <summary>
+    /// Decodes an AND 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)
+    {
+        // Set the mnemonic
+        instruction.Mnemonic = "and";
+        
+        int position = Decoder.GetPosition();
+        
+        if (position >= Length)
+        {
+            return false;
+        }
+        
+        // Read the ModR/M byte
+        var (mod, reg, rm, memOperand) = ModRMDecoder.ReadModRM();
+        
+        // Get register name
+        string regName = ModRMDecoder.GetRegisterName(reg, 32);
+        
+        // For mod == 3, both operands are registers
+        if (mod == 3)
+        {
+            string rmRegName = ModRMDecoder.GetRegisterName(rm, 32);
+            instruction.Operands = $"{rmRegName}, {regName}";
+        }
+        else // Memory operand
+        {
+            instruction.Operands = $"{memOperand}, {regName}";
+        }
+        
+        return true;
+    }
+}