quartus仿真的时候为什么会出现Error: Run Generate Functional Simulation Netlist (quartus_map option --generate_functional_sim_netlist) to generate functional simulation netlist for top level entity "option" before running the Simulator (quartus_sim)请问这是怎么回事啊？可以进行时序仿真但是不能进行功能仿真！谢谢！