As digital systems becomes more complex,it becomes increasingly important to verify the functionality of a design before implementing it in a system,a Test Bench source includes mainly some aspects:
0,set up time scale and operating precision.

1,instantiation


2,Reg and Wire Declarations


3,initial and always(clock,reset)


waring:

4,Printing during simulusation



5,TASK


原文:http://www.cnblogs.com/rrttp/p/5894694.html