diff --git a/op000.py b/op000.py
index 80b3cdc..5a5bf0e 100644
--- a/op000.py
+++ b/op000.py
@@ -116,6 +116,10 @@ def op000_dispatcher(cpu, inst):
                 op_rtt(cpu, inst)
             elif inst == 1:
                 op_wait(cpu, inst)
+            elif inst == 3:
+                raise PDPTraps.BPT
+            elif inst == 4:
+                raise PDPTraps.IOT
             elif inst == 5:
                 op_reset(cpu, inst)