diff --git a/tests/asu_tb.sv b/tests/asu_tb.sv
index e0285fb..63069d5 100644
--- a/tests/asu_tb.sv
+++ b/tests/asu_tb.sv
@@ -1,6 +1,6 @@
 `include "asu.sv"
 
-module asu_tb #(width=8)();
+module asu_tb #(width=4)();
     logic [0:0] op;
     logic [width-1:0] A;
     logic [width-1:0] B;