myhdl-list

[myhdl-list] Suspending/Resuming/Stopping a simulation

[Frank P. <pal...@co...>]

Hello,

I'm interested in suspending a simulation after a certain event, and =
then
resuming again, or possibly stopping.  The Simulation.run() call works =
for a
fixed number of cycles.  Is there a way that I can use exceptions to do
this?  I noticed that myhdl uses SuspendSimulation and StopSimulation
internally to do this.

This might be a nice feature in general.  One could write a testbed =
which
changes based on the simulation results. :) =20

Thanks,
Frank

Re: [myhdl-list] Suspending/Resuming/Stopping a simulation

[bedros <be...@ya...>]

I use StopSimulation exception frequently if there's
an invalid condition in my simulation such as reading
from an empty FIFO.

eg: if ready_sig and FIFO.empty:
           raise StopSimulation,  "ERROR: reading from
empty fifo"

I couldn't find anything about SuspendSimulation, not
even in MyHDL 0.4 documents. Where did you find it?

-Bedros

--- Frank Palazzolo <pal...@co...> wrote:
> 
> Hello,
> 
> I'm interested in suspending a simulation after a
> certain event, and then
> resuming again, or possibly stopping.  The
> Simulation.run() call works for a
> fixed number of cycles.  Is there a way that I can
> use exceptions to do
> this?  I noticed that myhdl uses SuspendSimulation
> and StopSimulation
> internally to do this.
> 
> This might be a nice feature in general.  One could
> write a testbed which
> changes based on the simulation results. :)  
> 
> Thanks,
> Frank
> 
> 
> 
> 
>
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RE: [myhdl-list] Suspending/Resuming/Stopping a simulation

[Frank P. <pal...@co...>]

>I couldn't find anything about SuspendSimulation, not
>even in MyHDL 0.4 documents. Where did you find it?

I just looked in the code...the beauty of open source :)

-Frank

RE: [myhdl-list] Suspending/Resuming/Stopping a simulation

[bedros <be...@ya...>]

you could raise a SuspendSimulation exception and use
"try" in the top level to catch it, fix it, and then
resume the simulation by executing "run" method again.



--- Frank Palazzolo <pal...@co...> wrote:
> 
> >I couldn't find anything about SuspendSimulation,
> not
> >even in MyHDL 0.4 documents. Where did you find it?
> 
> I just looked in the code...the beauty of open
> source :)
> 
> -Frank
> 
> 
> 
> 
>
-------------------------------------------------------
> This SF.Net email sponsored by Black Hat Briefings &
> Training.
> Attend Black Hat Briefings & Training, Las Vegas
> July 24-29 - 
> digital self defense, top technical experts, no
> vendor pitches, 
> unmatched networking opportunities. Visit
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> _______________________________________________
> myhdl-list mailing list
> myh...@li...
>
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> 

[myhdl-list] Re: Suspending/Resuming/Stopping a simulation

[Jan D. <ja...@ja...>]

bedros wrote:
> you could raise a SuspendSimulation exception and use
> "try" in the top level to catch it, fix it, and then
> resume the simulation by executing "run" method again.

(Sorry for the delayed response.)

It's more complicated. First, the run method catches
this exception itself. Moreover, it's not intended for
users to raise it. The simulation has both "real" time
steps and delta time steps. When you suspend, and then
continue, no events should be missed. Simply allowing
suspends at any moment makes this complicated. For that
reason the actual suspend occurs at a well defined
moment: at the end of a timestep, after delta cycle
convergence, right before real time is increased.

Probably the exception should be renamed _SuspendSimulation
to make this clear. This also explains why this exception
is not documented - you shouldn't use it.

The desired functionality could be implemented by introducing
a function, e.g. called suspend(), that a user could call.
This would set some global variable, and at the right time
the run method could then raise an exception that a user
could catch. In fact, we would need an exception that a
user would not be able to raise, only catch ... and this
would have to enforced by code to avoid mistakes. No
idea whether this is possible. Doesn't seem obvious, but
this is Python :-)

Regards, Jan

> 
> 
> 
> --- Frank Palazzolo <pal...@co...> wrote:
> 
>>>I couldn't find anything about SuspendSimulation,
>>
>>not
>>
>>>even in MyHDL 0.4 documents. Where did you find it?
>>
>>I just looked in the code...the beauty of open
>>source :)
>>
>>-Frank
>>
>>
>>
>>
>>
> 
> -------------------------------------------------------
> 
>>This SF.Net email sponsored by Black Hat Briefings &
>>Training.
>>Attend Black Hat Briefings & Training, Las Vegas
>>July 24-29 - 
>>digital self defense, top technical experts, no
>>vendor pitches, 
>>unmatched networking opportunities. Visit
>>www.blackhat.com
>>_______________________________________________
>>myhdl-list mailing list
>>myh...@li...
>>
> 
> https://lists.sourceforge.net/lists/listinfo/myhdl-list
> 
> 
> 
> 
> -------------------------------------------------------
> This SF.Net email sponsored by Black Hat Briefings & Training.
> Attend Black Hat Briefings & Training, Las Vegas July 24-29 - 
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