1 files changed, 18 insertions, 0 deletions
diff --git a/src/Noddybox.Emulation.EightBit/ICpu.cs b/src/Noddybox.Emulation.EightBit/ICpu.cs
index 9d1909c..1ee7781 100644
--- a/src/Noddybox.Emulation.EightBit/ICpu.cs
+++ b/src/Noddybox.Emulation.EightBit/ICpu.cs
@@ -20,6 +20,15 @@ using System;
 namespace Noddybox.Emulation.EightBit
 {
     /// <summary>
+    /// Defines a delegate that will be called after an instruction.
+    /// </summary>
+    /// <param name="sender">The CPU being used.  All state will be upto date prior to invoking
+    /// the callback.</param>
+    /// <returns>True if the CPU should continue executing, or false if not.  Users should simply
+    /// return Clock.VBL if they need no other than clock control.</returns>
+    public delegate bool CpuCallback(object sender);
+
+    /// <summary>
     /// Defines an 8-bit CPU.
     /// </summary>
     public interface ICpu
@@ -48,6 +57,15 @@ namespace Noddybox.Emulation.EightBit
         void Run();
 
         /// <summary>
+        /// Runs the CPU until the callback tells it to stop.
+        /// </summary>
+        /// <param name="callback">A delegate that is called after every completed instruction
+        /// cycle and tells the CPU when to stop running.  Note that at least one instruction
+        /// is always executed as the callback is made after the cycle has completed.
+        /// </param>
+        void Run(CpuCallback callback);
+
+        /// <summary>
         /// Generates a maskable interrupt to the CPU.
         /// </summary>
         /// <param name="value">Optional value from an interrupting device.  May be ignored depending on the CPU type.</param>