Fixed FnstswHandler test by registering the handler in InstructionHandlerFactory

X86Disassembler/X86/Handlers/Pop/PopRegHandler.cs

@@ -0,0 +1,49 @@
+namespace X86Disassembler.X86.Handlers.Pop;
+
+/// <summary>
+/// Handler for POP r32 instruction (0x58-0x5F)
+/// </summary>
+public class PopRegHandler : InstructionHandler
+{
+    /// <summary>
+    /// Initializes a new instance of the PopRegHandler 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 PopRegHandler(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 >= 0x58 && opcode <= 0x5F;
+    }
+    
+    /// <summary>
+    /// Decodes a POP 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 = "pop";
+        
+        // Register is encoded in the low 3 bits of the opcode
+        int reg = opcode & 0x07;
+        string regName = ModRMDecoder.GetRegisterName(reg, 32);
+        
+        // Set the operands
+        instruction.Operands = regName;
+        
+        return true;
+    }
+}