Re: [myhdl-list] debugging Cosimulation with Icarus Verilog

[Günter D. <dan...@we...>]

Jan Decaluwe wrote:
...

> 
> Based on previous experience, I'm quite reluctant to make big
> changes. Given that cver works with the method as implemented,
> I'm inclined to think that in principle Icarus should behave the
> same it Icarus vpi is done properly.

I have filed a bug report (#2048463) for the cbValueChange issue on the 
Icarus bug tracker.

http://sourceforge.net/tracker/index.php?func=detail&aid=2048463&group_id=149850&atid=775997

One of the developers already confirmed some issues and also named the 
vpiSuppressTime, which is the reason for the necessary change below:

> 
> I do see a difference that may be significant between the two
> files:
> 
>    // icarus stops on the following line but shouldn't
>    // cb_data_s.value = &value_s;
>    cb_data_s.value = NULL;
> 

In the bug report I also mentioned the time 0 issue, which is, that I 
see a call back happening at time 0, when no signal assignment happens. 
I got a reply that the Icarus developers discussed that before and if I 
think that this is a wrong behavior I should file another bug report.

I compared the Cver behavior with Riviera and both behave the same way. 
If no signal assignment happens at time 0, there is no callback. I will 
investigate that some more and then also file it as bug report.

Guenter