为什么我的功能仿真会出现错误 时序仿真可以用。。。。求指教

错误:生成网表功能模拟运行(quartus_map mux21a——generate_functional_sim_netlist)为顶层实体生成网表功能模拟运行模拟器之前“mux21a”(quartus_sim)



Error: Run Generate Functional Simulation Netlist (quartus_map mux21a --generate_functional_sim_netlist) to generate functional simulation netlist for top level entity "mux21a" before running the Simulator (quartus_sim)