Re: new AMS LRM 2.2 draft c - parameter descriptions

Kevin,

BSIM4 has nearly 400 parameters. How is creating 3 line functions for each
of these 400 parameters less typing than "---"descr" at the end of each
line? If every module had the same parameters then maybe this is true if
say a CAD group provides a set of predefined parameters but my experience
with hundreds of Verilog-A modules implies that this would not buy users
much. Cannot imagine telling my users that to put a description on a
parameter that they have to do this class programming stuff for each
parameter and thus the description declaration would be separate from
use. Likewise, the description is lost in the module for those debugging
it since it is stored separately in the class and tools would need to read
both the class and the module for the descriptions to be displayed, this
may impact some tools in the flow.

At some point the boys in IEEE and SV need to be a bit more flexible and
consider the needs of their analog brothers. If not then we will never
sync the two standards together, we cannot force every analog requirement
into a digital programming language. I think the only two options are
putting more flexibility in attributes as Geoffrey proposed or something
like Geoffrey and the team has proposed with the ---"string".

Jon

At 04:32 PM 5/26/2004, Kevin Cameron wrote:

>I really don't think the syntax for units and descriptions will fly with
>the SV & IEEE. SV has classes which makes it unnecessary to do it that
>way: all you need is a base class which has the two strings or string
>functions and you can create the types you need as subclasses e.g.:-
>class unit_desc; // this could be a built-in
> real value;
> virtual function string unit(); endfunction;
> virtual function string desc(); endfunction;
>endclass
>
>// these would be in a header file
>class Ohms extends unit_desc;
> function string unit(); return "Ohms"; endfunction;
>endclass
>
>class Resistance extends Ohms;
> function string desc(); return "Resistance"; endfunction;
>endclass
>
>....
>// Your code -
>
>parameter Resistance from [0:inf);
>
>- lots less typing if you have a lot of thing you want to be of type
>Resistance.
>
>You can also do paramaterized classes which would let you do something like:
>parameter unit_desc#("Ohms","Resistance") from [0:inf);
>
>- but an approach that requires you to enter the strings for every
>individual parameter is tedious and eror-prone, so you would probably do:-
>typedef unit_desc#("Ohms","Resistance") Resistance;
>....
>
>parameter Resistance from [0:inf);
>
>I would just scrub section 3.2.3.
>
>Kev.
>
>Geoffrey.Coram wrote:
>>
>>Hi -
>>I've uploaded a new draft of the LRM to the eda.org web site.
>>
>
>
>--
>Kevin Cameron, CPU Technology, CA 94588, Tel.: (925) 225 4862

***********************************************************
Jonathan L. Sanders
Product Engineering Director
Custom IC Solutions
Cadence Design Systems, Inc.
555 River Oaks Pkwy
San Jose, CA. 95134
  INTERNET:jons@cadence.com Tel: (408) 428-5654 Fax : (408) 944-7027
***********************************************************
Received on Wed May 26 17:16:06 2004