diff --git a/lib/m2/x86/x86_defs.M1 b/lib/m2/x86/x86_defs.M1
index c87d4c4d..824e8964 100644
--- a/lib/m2/x86/x86_defs.M1
+++ b/lib/m2/x86/x86_defs.M1
@@ -1,4 +1,5 @@
 ## Copyright (C) 2017 Jeremiah Orians
+## Copyright (C) 2021 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
 ## This file is part of M2-Planet.
 ##
 ## M2-Planet is free software: you can redistribute it and/or modify
@@ -68,6 +69,7 @@ DEFINE MULTIPLY_eax_by_ebx_into_eax F7EB
 DEFINE MULTIPLYS_eax_by_ebx_into_eax F7E3
 DEFINE NULL 00000000
 DEFINE NOT_eax F7D0
+DEFINE NOP 00000000
 DEFINE OR_eax_ebx 09D8
 DEFINE POP_eax 58
 DEFINE POP_ebx 5B