split float handlers

X86Disassembler/X86/Handlers/FloatingPoint/LoadStoreFloat64Handler.cs

@@ -0,0 +1,120 @@
+namespace X86Disassembler.X86.Handlers.FloatingPoint;
+
+/// <summary>
+/// Handler for floating-point load/store float64 operations (DD opcode)
+/// </summary>
+public class LoadStoreFloat64Handler : FloatingPointBaseHandler
+{
+    // DD opcode - load/store float64
+    private static readonly string[] Mnemonics =
+    [
+        "fld",
+        "??",
+        "fst",
+        "fstp",
+        "frstor",
+        "fnsave",
+        "fnstsw"
+    ];
+
+    /// <summary>
+    /// Initializes a new instance of the LoadStoreFloat64Handler 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 LoadStoreFloat64Handler(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 == 0xDD;
+    }
+
+    /// <summary>
+    /// Decodes a floating-point instruction for load/store float64 operations
+    /// </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)
+        {
+            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);
+
+        // Set the mnemonic based on the opcode and reg field
+        instruction.Mnemonic = Mnemonics[reg];
+
+        // For memory operands, set the operand
+        if (mod != 3) // Memory operand
+        {
+            string operand = ModRMDecoder.DecodeModRM(mod, rm, false);
+
+            if (reg == 0 || reg == 2 || reg == 3) // fld, fst, fstp
+            {
+                instruction.Operands = $"qword ptr {operand}";
+            }
+            else // frstor, fnsave, fnstsw
+            {
+                instruction.Operands = operand;
+            }
+        }
+        else // Register operand (ST(i))
+        {
+            // Special handling for register-register operations
+            if (reg == 0) // FFREE
+            {
+                instruction.Mnemonic = "ffree";
+                instruction.Operands = $"st({rm})";
+            }
+            else if (reg == 2) // FST
+            {
+                instruction.Mnemonic = "fst";
+                instruction.Operands = $"st({rm})";
+            }
+            else if (reg == 3) // FSTP
+            {
+                instruction.Mnemonic = "fstp";
+                instruction.Operands = $"st({rm})";
+            }
+            else if (reg == 4) // FUCOM
+            {
+                instruction.Mnemonic = "fucom";
+                instruction.Operands = $"st({rm})";
+            }
+            else if (reg == 5) // FUCOMP
+            {
+                instruction.Mnemonic = "fucomp";
+                instruction.Operands = $"st({rm})";
+            }
+            else
+            {
+                // Unknown instruction
+                instruction.Mnemonic = "??";
+                instruction.Operands = "";
+            }
+        }
+
+        return true;
+    }
+}