Re: [myhdl-list] yield before the end of a simulation

[Christopher F. <chr...@gm...>]

On Tuesday, December 20, 2011, Oscar Diaz <osc...@gm...> wrote:
> 2011/12/20 Christopher Felton <chr...@gm...>:
>> On 12/20/2011 5:35 AM, Oscar Diaz wrote:
>>> Hi
>>>
>>> I have a testbench that needs to do some asserts at the end of a
>>> simulation. However, I couldn't find an elegant way to do it. Right
>>> now I'm passing to the testbench generator the same duration as in
>>> "Simulation.run(duration)" , so I can do a "yield delay(duration-1)"
>>> and do the final asserts (by the way, in my case all my simulations
>>> have a defined duration). I tried to catch the StopSimulation
>>> exception, but it doesn't work inside a generator. Any ideas? Thanks!
>>>
>>> Best regards
>>>
>>
>> I believe you can catch exceptions in generators.  At least the
>> generator PEP says so and the following works.
>>
>> ~~~ [Code Snip] ~~~
>> from myhdl import *
>> def test():
>>     @instance
>>     def ex_in_g():
>>         try:
>>             for ii in xrange(10):
>>                 yield delay(7)
>>             raise StopSimulation
>>
>>         except Exception, e:
>>             print("Caught exception %s" % (str(e)))
>>             raise StopSimulation
>>
>>     return ex_in_g
>>
>> if __name__ == '__main__':
>>     Simulation(test()).run()
>> ~~~~~~~~~~~~~~~~~~~~~~~
>
> That's the case when the exception is raised inside the generator,
> which is not my case. I'm trying to something like this:
>
> ~~~ [Code Snip] ~~~
> from myhdl import *
> def test():
>    @instance
>    def ex_in_g():
>        try:
>            for ii in xrange(10):
>                yield delay(7)
>            # ideally it shouldn't got here
>            return
>
>        except Exception, e:
>        # or maybe better "except StopSimulation" ?
>            print("Caught exception %s" % (str(e)))
>            raise StopSimulation
>
>    return ex_in_g
>
> if __name__ == '__main__':
>    # fixed simulation time
>    Simulation(test()).run(50)
> ~~~~~~~~~~~~~~~~~~~~~~~
>
> It doesn't work because the exception is raised inside the run()
> method. Right now my project store the simulation duration to yield
> before raising StopSimulation, like this:
> ~~~ [Code Snip] ~~~
> from myhdl import *
> sim_duration = 100
> def test():
>    @instance
>    def main_block():
>        # do some stuff
>        return
>
>    @instance
>    def last_check():
>        yield delay(sim_duration - 1)
>        print "do some final asserts..."
>        return
>
>    return instances()
>
> if __name__ == '__main__':
>    Simulation(test()).run(sim_duration)
> ~~~~~~~~~~~~~~~~~~~~~~~
>
> Any ideas to improve this issue?
>
> Best regards
>
>>
>> Regards,
>> Chris
>>
>>

Another option you could try is to run the simulation from the test
function.  After the simulation completes the final state is preserved and
you can do the final checks.

I haven't tried it.  In the above example, the test function you could do
the following.

 Def test():
    ...
    Simulation((ex_in_g)).run()
     #checks
     # nothing to return

Regards,
Chris