1 files changed, 50 insertions, 0 deletions
diff --git a/Chip/BusDevice.cs b/Chip/BusDevice.cs
new file mode 100644
index 0000000..e1f559c
--- /dev/null
+++ b/Chip/BusDevice.cs
@@ -0,0 +1,50 @@
+namespace Q1Emu.Chip;
+
+using System.Runtime.CompilerServices;
+
+public abstract class BusDevice
+{
+    public BusDevice(u16 addressableStart, u16 addressableEnd)
+    {
+        this.AddressableStart = addressableStart;
+        this.AddressableEnd   = addressableEnd;
+    }
+    
+    public Bus Bus { get; set; }
+    public abstract u8 Read(u16 address);
+    public abstract void Write(u16 address, u8 value);
+    
+    public abstract ref8 ReadSeq(u16 address, u16 length);
+    public abstract void WriteSeq(u16 address, u16 length, ref8 value);
+    
+    public u16 ReadWord(u16 address)
+    {
+        ref8 data = this.ReadSeq(address, 2);
+        u16 value = Make.u16(data);
+        return value;
+    }
+    
+    public void WriteWord(u16 address, u16 value)
+    {
+        ref8 data = Make.ref8(value);
+        this.WriteSeq(address, 2, data);
+    }
+
+    public virtual void Clock() { }
+    public virtual void Reset() { }
+    
+    public void AttachToBus(Bus bus)
+    {
+        this.Bus = bus;
+        bus.Devices.Add(this);
+    }
+    
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    protected u16 GetRelativeAddress(u16 address)
+    {
+        return (u16) (address - this.AddressableStart);
+    }
+
+    public u16 AddressableStart { get; }
+    public u16 AddressableEnd   { get; }
+}
+\ No newline at end of file