diff --git a/hw/application_fpga/tb/application_fpga_sim.v b/hw/application_fpga/tb/application_fpga_sim.v
index 58c5600..00da22d 100644
--- a/hw/application_fpga/tb/application_fpga_sim.v
+++ b/hw/application_fpga/tb/application_fpga_sim.v
@@ -23,6 +23,10 @@
 `define verbose(debug_command)
 `endif
 
+`ifndef APP_SIZE
+`define APP_SIZE 0
+`endif
+
 module application_fpga_sim (
     input wire clk,