diff --git a/BizHawk.Emulation.Common/Interfaces/CoreComms.cs b/BizHawk.Emulation.Common/Interfaces/CoreComms.cs
index 70c5de1b00..3c29a1ee57 100644
--- a/BizHawk.Emulation.Common/Interfaces/CoreComms.cs
+++ b/BizHawk.Emulation.Common/Interfaces/CoreComms.cs
@@ -199,6 +199,17 @@ namespace BizHawk.Emulation.Common
 			}
 		}
 
+		public void CallExecute(uint addr)
+		{
+			for (int i = 0; i < _writes.Count; i++)
+			{
+				if (_writeAddrs[i] == addr)
+				{
+					_writes[i]();
+				}
+			}
+		}
+
 		public bool HasReads { get { return _reads.Any(); } }
 		public bool HasWrites { get { return _writes.Any(); } }
 
diff --git a/BizHawk.Emulation/CPUs/MOS 6502X/Execute.cs b/BizHawk.Emulation/CPUs/MOS 6502X/Execute.cs
index eecfa4360f..0bd0893c8d 100644
--- a/BizHawk.Emulation/CPUs/MOS 6502X/Execute.cs	
+++ b/BizHawk.Emulation/CPUs/MOS 6502X/Execute.cs	
@@ -590,6 +590,7 @@ namespace BizHawk.Emulation.CPUs.M6502
             {
                 if (debug) Console.WriteLine(State());
                 branch_irq_hack = false;
+								if (OnExecFetch != null) OnExecFetch(PC);
                 opcode = ReadMemory(PC++);
                 mi = -1;
             }
diff --git a/BizHawk.Emulation/CPUs/MOS 6502X/MOS6502X.cs b/BizHawk.Emulation/CPUs/MOS 6502X/MOS6502X.cs
index bfba3f75c3..f04539aeda 100644
--- a/BizHawk.Emulation/CPUs/MOS 6502X/MOS6502X.cs	
+++ b/BizHawk.Emulation/CPUs/MOS 6502X/MOS6502X.cs	
@@ -180,6 +180,9 @@ namespace BizHawk.Emulation.CPUs.M6502
 		public Func<ushort, byte> PeekMemory;
 		public Action<ushort, byte> WriteMemory;
 
+		//this only calls when the first byte of an instruction is fetched.
+		public Action<ushort> OnExecFetch;
+
 		public void SetCallbacks
 		(
 			Func<ushort, byte> ReadMemory,
diff --git a/BizHawk.Emulation/Consoles/Nintendo/NES/Core.cs b/BizHawk.Emulation/Consoles/Nintendo/NES/Core.cs
index c2e7590143..8330d82bed 100644
--- a/BizHawk.Emulation/Consoles/Nintendo/NES/Core.cs
+++ b/BizHawk.Emulation/Consoles/Nintendo/NES/Core.cs
@@ -160,6 +160,7 @@ namespace BizHawk.Emulation.Consoles.Nintendo
 					}
 				};
 			cpu.BCD_Enabled = false;
+			cpu.OnExecFetch = ExecFetch;
 			ppu = new PPU(this);
 			ram = new byte[0x800];
 			CIRAM = new byte[0x800];
@@ -512,6 +513,11 @@ namespace BizHawk.Emulation.Consoles.Nintendo
 		//old data bus values from previous reads
 		public byte DB;
 
+		public void ExecFetch(ushort addr)
+		{
+			CoreComm.MemoryCallbackSystem.CallExecute(addr);
+		}
+
 		public byte ReadMemory(ushort addr)
 		{
 			byte ret;