[myhdl-list] Re: myhdl on windows platform?

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

Chun Lin Zhang wrote:
> Hi, all,
>  
> I tried to use myhdl to co-simulate with verilog on windows platform 
> today. I got the following error messages.
>  
> Traceback (most recent call last):
>   File 
> "C:\Python23\lib\site-packages\Pythonwin\pywin\framework\scriptutils.py", 
> line 310, in RunScript
>     exec codeObject in __main__.__dict__
>   File "D:\proj\myhdl-0.4\cosimulation\mti\test\test.py", line 17, in ?
>     def stimulus(a, b):
>   File "C:\Python23\Lib\site-packages\myhdl\_Cosimulation.py", line 71, 
> in __init__
>     child_pid = self._child_pid = os.fork()
> AttributeError: 'module' object has no attribute 'fork'
>  
> I queried the library reference of python, it DO mentioned that os.fork 
> is only available in UNIX.
>  
> So I guess MyHDL doesn't have the ability to co-sim with Verilog on 
> windows currently. However, do you have any plan to support this on 
> windows recently?

Hi:

In general, I would like MyHDL run on any Python platform.
I try to take advantage of Python's portability.
However, I only use Linux as a development platform myself,
and I don't have the possibility to test/maintain multiple
platforms. This is one area where I have to rely on outside
help.

The closer one gets to the operating system, the more likely
it is that problems will appear. The way co-simulation is
currently set up, using fork to create new processes, is
one example. Note that "native" MyHDL shouldn't pose any
problem, and if it does, it should be possible to solve
it easily.

For this concrete problem: I wasn't fully aware of the
fork issue, but I have done some investigations. It seems
indeed that this is not available on Windows, and cannot
even be emulated easily. From what I read it may be
availabe on NT, but even then it's not certain that Python
will support it.

Your best bet, I think, is to compile Python under Cygwin
on Windows, instead of using the native Python. This should
give you fork as I understand it.

This may be a reasonable solution, because I wonder what
Verilog simulator you are using? If it is Icarus, I believe
that the way it works on Windows is by using Cygwin anyway.

Note: I never used Cygwin myself, but it seems to get good
press.

Another solution, perhaps, would be one for me: using another
approach for co-simulation. It might be possible to use
threads instead of processes, and this should work on all
platforms (using Python's threading module).
I will need to investigate this further, and I have no idea
what problems I will encounter, so don't count on this
one anytime soon.

Hope this helps,

Jan

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Jan Decaluwe - Resources bvba - http://jandecaluwe.com
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