diff --git a/src/emu/i8088.rs b/src/emu/i8088.rs
index a05db3b..d5d2646 100644
--- a/src/emu/i8088.rs
+++ b/src/emu/i8088.rs
@@ -138,7 +138,7 @@ macro_rules! step {
       let opcode = $cpu.next_ip($bus);
       match(opcode) {
         $( $code => step!(@code (), $cpu, $bus, $name, $cycles, ($($args $(= $argrhs)?)*)) ),*,
-        _ => unimplemented!("opcode: {:02X}", opcode)
+        _ => unimplemented!("opcode: {:02X}\ncpu: {:#X?}", opcode, $cpu)
       }
     }
   }