Unified ADC accumulator handlers into a single handler

X86Disassembler/X86/Handlers/Adc/AdcImmToRm16SignExtendedHandler.cs

@@ -0,0 +1,84 @@
+namespace X86Disassembler.X86.Handlers.Adc;
+
+using Operands;
+
+/// <summary>
+/// Handler for ADC r/m16, imm8 (sign-extended) instruction (0x83 /2 with 0x66 prefix)
+/// </summary>
+public class AdcImmToRm16SignExtendedHandler : InstructionHandler
+{
+    /// <summary>
+    /// Initializes a new instance of the AdcImmToRm16SignExtendedHandler class
+    /// </summary>
+    /// <param name="decoder">The instruction decoder that owns this handler</param>
+    public AdcImmToRm16SignExtendedHandler(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)
+    {
+        // ADC r/m16, imm8 (sign-extended) is encoded as 0x83 /2 with 0x66 prefix
+        if (opcode != 0x83)
+        {
+            return false;
+        }
+
+        // Check if we have enough bytes to read the ModR/M byte
+        if (!Decoder.CanReadByte())
+        {
+            return false;
+        }
+
+        // Check if the reg field of the ModR/M byte is 2 (ADC)
+        var reg = ModRMDecoder.PeakModRMReg();
+
+        // Only handle when the operand size prefix is present
+        return reg == 2 && Decoder.HasOperandSizePrefix();
+    }
+
+    /// <summary>
+    /// Decodes a ADC r/m16, imm8 (sign-extended) 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.Adc;
+
+        // For ADC r/m16, imm8 (sign-extended) (0x83 /2 with 0x66 prefix):
+        // - The r/m field with mod specifies the destination operand (register or memory)
+        // - The immediate value is the source operand (sign-extended from 8 to 16 bits)
+        var (_, _, _, destinationOperand) = ModRMDecoder.ReadModRM16();
+
+        // Note: The operand size is already set to 16-bit by the ReadModRM16 method
+
+        // Check if we have enough bytes for the immediate value
+        if (!Decoder.CanReadByte())
+        {
+            return false;
+        }
+
+        // Read the immediate value (sign-extended from 8 to 16 bits)
+        short imm16 = (sbyte)Decoder.ReadByte();
+
+        // Create the immediate operand
+        var sourceOperand = OperandFactory.CreateImmediateOperand((ushort)imm16, 16);
+
+        // Set the structured operands
+        instruction.StructuredOperands = 
+        [
+            destinationOperand,
+            sourceOperand
+        ];
+
+        return true;
+    }
+}