SystemVerilog TestBench模拟（VCS）的不活动杀死开关

Question

嗨，谢谢你看到这个。

我对SystemVerilog仿真的不活动杀戮杀戮的想法思考。

是否有一种方法在运行“SIMV”时，延长（可编程）的不活动持续时间可以触发内部事件来调用'$完成'？或者可以使用VCS命令？

让头脑风暴。并告诉我是否尚不清楚。

rrs

Answer 1

In VHDL I use a resolved signal.

Each process that generates or analyses data writes 0 to that signal while it is working. Once it is in a state for the simulation to finish, it writes 1.

Only when all processes are happy does the signal change state to a 1 (it's either X or 0 the rest of the time).

The clock generation processes monitor this signal and when it becomes 1 they stop producing clock pulses; no further transitions are scheduled, and the simulator knows to stop.

Presumably Verilog can do something similar.

Answer 2

Inside the chip design companies that I've worked for, this is called a "quiescent check", but I'm not sure if that's an industry standard name. You implement "instrumentation code" that checks that the system has acheived quiescence. V̶e̶r̶i̶s̶i̶t̶y̶'̶s̶ Cadence's Specman-e tool does this quite elegantly with its objection to end of test mechanism (raise_objection(MAIN_TEST_DONE)/drop_objection(MAIN_TEST_DONE)). Essentially, monitors throughout throughout the system "raise" an objection at the beginning of simulation ( i.e. increment the counter), then when the simulation runs, they determine that their piece of the DUT is quiescent and they "lower" the objection (i.e. decrement this global counter). When there are no more objections to ending the test, (i.e. the global counter is 0), then $finish is called. The monitors can raise and lower objections throughout the test, but if and when the counter ever reaches 0, the test is $finish'd.

Universal Verification Methodology (UVM) took up this methodology from Specman and it is described here in their UVM Reference Manual. UVM is implemented with Verilog first and foremost, so you could definitely use their freely available library to implement "quiescent checking". Cadence's Specman UVM reference manual also describes this mechanism at http://support.cadence.com . Unfortunately, Cadence requires that you be a customer before they'll show you their documents and thus you must use a non-Google search engine to find what you want. It's a bit of a pain.