[sv-bc] Re: configs and params

From: Don Mills <mills_at_.....>
Date: Thu Sep 13 2007 - 17:23:44 PDT

Mark Hartoog wrote:

There are a lot of questions this leaves open.

In what scope are identifiers resolved in the parameter override 
expressions? 
  

Mark, I probably need help specifying this.  I would assume that the scope would be either the hierarchical level if the parameter is being overridden for the whole instance, whereas the scope would be just for an instantiation if that is what is being specified to be overridden.

Are there any restrictions on the hierarchical names of parameters 
that may be used in an override. If there are no restrictions,
then it is possible to produce parameter evaluation loops.
It is already possible to do this with defparams.
  

I have thought about this some.  In some ways this can be a direct replacement of defparams if there are no restrictions to hierarchical names of parameters to be overridden.  Perhaps the restrictions should be to only allow parameter overrides at the top module level or on specific instantiations.

You are adding localparams to configuration. Does this make
a configuration a scope? Do we need to allow things like
package import statements in configurations too?
  

The reason I put in a localparams was to have a way to have constants in the configuration which could be used to set a common value for overriding a number of parameters.  Is there a better way - without using macros?  I do not intend to make configuration a scope - but maybe it becomes such as a result of localparams.  I do not think that package imports make any since at all inside a configuration.  Comments?

Have you thought about type parameters and passing of user 
defined types to type parameters? 
 
  

Adam asked the same - I have cut and pasted my response to him below:
My  preference for now is to keep this simple.  If possible, I would prefer to only allow overrides of  values and not types, but I see no reason why my proposed syntax couldn't also be applied to types. 

What can be proposed and yet kept simple enough to have any possibility of making it into the LRM this go around?

-----Original Message-----
From: Don Mills [mailto:mills@lcdm-eng.com] 
Sent: Thursday, September 13, 2007 10:47 AM
To: Gordon Vreugdenhil; Bresticker, Shalom; 
adam.krolnik@verisilicon.com; Mark Hartoog
Subject: configs and params

Attached is my first pass at actual text to be submitted as a 
mantis item.  I wanted to run this by you guys first to make 
sure that I did not have any glaring problems.  I assume that 
the text will need some work, we can either clean things up 
within the confines of this small group or I could go ahead 
and open the mantis item and we could have our discussion on 
the reflector.  What is the preference?

dm

--
==========================================================
Don Mills
mills@lcdm-eng.com
www.lcdm-eng.com
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-- 
==========================================================
Don Mills
mills@lcdm-eng.com
www.lcdm-eng.com
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