1 files changed, 1 insertions, 1 deletions
diff --git a/survey.py b/survey.py
index 23fac27..442ef11 100644
--- a/survey.py
+++ b/survey.py
@@ -24,7 +24,7 @@ def observe(part, rel_addr, map):
 
         mode, size, shift = tag_re.match(tag).groups()
         size = int(size)
-        shift = int(shift)
+        shift = int(shift) if shift else 0
 
         if mode == 'imm':
             addr = bits.u(addr, size)