implement shift and rotate handlers. Fix tests

X86Disassembler/X86/Handlers/Shift/ShlRm32ByImmHandler.cs

@@ -0,0 +1,72 @@
+using X86Disassembler.X86.Operands;
+
+namespace X86Disassembler.X86.Handlers.Shift;
+
+/// <summary>
+/// Handler for SHL r/m32, imm8 instruction (0xC1 /4)
+/// </summary>
+public class ShlRm32ByImmHandler : InstructionHandler
+{
+    /// <summary>
+    /// Initializes a new instance of the ShlRm32ByImmHandler class
+    /// </summary>
+    /// <param name="decoder">The instruction decoder that owns this handler</param>
+    public ShlRm32ByImmHandler(InstructionDecoder decoder)
+        : base(decoder)
+    {
+    }
+
+    /// <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)
+    {
+        // SHL r/m32, imm8 is encoded as 0xC1 /4
+        if (opcode != 0xC1)
+            return false;
+
+        // Check if we can read the ModR/M byte
+        if (!Decoder.CanReadByte())
+            return false;
+
+        // Check if the reg field of the ModR/M byte is 4 (SHL)
+        var reg = ModRMDecoder.PeakModRMReg();
+        return reg == 4; // 4 = SHL
+    }
+
+    /// <summary>
+    /// Decodes a SHL r/m32, 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)
+    {
+        // Set the instruction type
+        instruction.Type = InstructionType.Shl;
+
+        // Read the ModR/M byte
+        var (_, _, _, operand) = ModRMDecoder.ReadModRM();
+
+        // Check if we can read the immediate byte
+        if (!Decoder.CanReadByte())
+            return false;
+
+        // Read the immediate byte (shift count)
+        byte imm8 = Decoder.ReadByte();
+
+        // Create an immediate operand for the shift count
+        var immOperand = OperandFactory.CreateImmediateOperand(imm8);
+
+        // Set the structured operands
+        instruction.StructuredOperands = 
+        [
+            operand,
+            immOperand
+        ];
+
+        return true;
+    }
+}