diff --git a/tools/fix_regs.py b/tools/fix_regs.py
index 3a24a3f4..954a2873 100755
--- a/tools/fix_regs.py
+++ b/tools/fix_regs.py
@@ -1,4 +1,5 @@
 import re
+import sys
 
 def parse_defs(fname):
 	f = open(fname, "r")