split float handlers

X86Disassembler/X86/Handlers/FloatingPoint/FnstswHandler.cs

@@ -0,0 +1,63 @@
+namespace X86Disassembler.X86.Handlers.FloatingPoint;
+
+/// <summary>
+/// Handler for FNSTSW instruction (0xDFE0)
+/// </summary>
+public class FnstswHandler : InstructionHandler
+{
+    /// <summary>
+    /// Initializes a new instance of the FnstswHandler 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 FnstswHandler(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)
+    {
+        // FNSTSW is a two-byte opcode (0xDF 0xE0)
+        if (opcode == 0xDF)
+        {
+            int position = Decoder.GetPosition();
+            if (position < Length && CodeBuffer[position] == 0xE0)
+            {
+                return true;
+            }
+        }
+        
+        return false;
+    }
+    
+    /// <summary>
+    /// Decodes an FNSTSW 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 || CodeBuffer[position] != 0xE0)
+        {
+            return false;
+        }
+        
+        // Skip the second byte of the opcode
+        Decoder.SetPosition(position + 1);
+        
+        // Set the mnemonic and operands
+        instruction.Mnemonic = "fnstsw";
+        instruction.Operands = "ax";
+        
+        return true;
+    }
+}