Added AY38912 support

Core/Io/IO_Bus.cs

@@ -1,6 +1,7 @@
-using System.Diagnostics;
+using Core.Audio;
 using Core.Interfaces;
 using Core.Memory;
+using System.Diagnostics;
 using static System.Runtime.InteropServices.JavaScript.JSType;
 
 namespace Core.Io
@@ -8,6 +9,7 @@ namespace Core.Io
     public class IO_Bus
     {
         public byte BorderColourIndex { get;  set; } = 7;
+        public Ay38912 AyChip { get; private set; } = new Ay38912();
         public byte KempstonState { get; set; } = 0x00;
         public bool BeeperState { get; private set; } = false;
         public byte[] KeyboardRows = new byte[8] { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
@@ -49,9 +51,13 @@ namespace Core.Io
             {
                 return KempstonState; 
             }
+            // AY-3-8912 Data Read (Port 0xFFFD)
+            if ((portAddress & 0xC002) == 0xC000)
+            {
+                return AyChip.ReadRegister();
+            }
 
-            //Return 0xFF for unhandled ports
-            return 0x00;
+            return 0xFF; // Default floating bus
         }
 
         public void WritePort(ushort portAddress, byte portValue)
@@ -79,6 +85,16 @@ namespace Core.Io
             {
                 _memory.HandlePaging(0x1FFD, portValue);
             }
+            // AY-3-8912 Register Select (Port 0xFFFD)
+            if ((portAddress & 0xC002) == 0xC000)
+            {
+                AyChip.SelectRegister(portValue);
+            }
+            // AY-3-8912 Data Write (Port 0xBFFD)
+            else if ((portAddress & 0xC002) == 0x8000)
+            {
+                AyChip.WriteRegister(portValue);
+            }
         }
     }
 }