Re: Port Proposal in HTML

From: Adam Krolnik (adamk@cyrix.com)
Date: Mon Jan 11 1999 - 06:13:55 PST


Good morning Mac:

A few simple comments:

1. I don't understand the parameter_port list functionality.
  A. Why is it # ( parameter blah...)? Doesn't this seem redundant
     to require two syntactic devices (the #() and 'parameter'.)
     I would consider folding the parameter declarations into
     the regular port list.
     
  B. You say, 'where the parameters are used to size the width of
     input, output and inout ports.' Does this mean, I have to
     record parameters for other purposes somewhere else? Or
     is this the place to declare parameters that can be redefined
     by the instantiation parameter override?
     
2. I don't see the usefulness to modify/extend the syntax for tasks/functions.
   It doesn't seem to buy anything except some consistency with module
   definitions. I presume this is exactly the reason it was introduced.
   Is there any other functionality extension that goes with it?
   
3. Okay, now I'm confused (you probably answered my questions in 1b already.)
   So the example of point 7 shows that not only parameters that can be
   overridden at instantiation time need to be declared above, but any
   locally computed parameters also need to be listed there (as shown by
   the example.) So does this mean that we still need the 'localparam'
   proposal to limit parameters that are overridable to a subset of
   the parameters defined in the parameter_port_list?! You probably
   don't want the name 'parameter_port' if you have to declare parameters
   that also are needed to compute declarations of the ports and are not
   allowed to be overridden at instantiation.

4. What about the initialization of registers (aka B14?)
   Should this be a valid port definition?
   
   output reg [7:0] out_byte = 'b0;
   
   Also, if this is allowed, it should be allowed for output port
   definitions of tasks.

<p>I want this functionality as part of the standard - I hate writing thrice the
ports!

<p> Adam Krolnik
    Verification Engineer
    Cyrix - NSC.
    Richardson TX. 75085



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