[sv-cc] Food for thought

Hi All,

Last week I asked everyone to consider the straw poll action item
which we have had open for a while. Here are some of my thoughts
to get the ball rolling.

I think it is not practical to replace the VPI data model with a new
one which solves a bunch of problems, but if we were to I would want
to fix the following (in no particular order):

   - Remove a whole bunch of redundant stuff that isn't used but was
     put in to match PLI 1.0 behavior. For example, on the nets
     diagram, we really don't need iterations on cont assign, prim term,
     path term, and tchk term. These are all covered by the load and
     driver iterations.
   - I would want to separate definition data and instance data. Create
     and instance object, and from it descend to a module, primitive, ...etc.
   - I would create a declarative object iteration from module, and
     get rid of all of the separate iterations on objects like nets, regs,
     ...etc.
   - I'd fix the typedef stuff so that it is separate from the type of
     a net/variable.
   - I'd fix the inconsistencies between nets and variables.
   - I'd introduce the concept of a reference to an object.

If we extend this to the interface itself, I would also do the following:

   - Reconsider the lifetime of a VPI handle.
   - Clean up the return values for the routines so that they consistently
     return FALSE on success and non-FALSE on failure, or NULL if they
     are returning a pointer/handle.
   - Try to come up with more extensible data structures for routines
     like vpi_register_cb() and vpi_put_value()/vpi_get_value().

Well, that is all I can think of off the top of my head. I don't know
if we'll have much time to talk about this today, so if you also have
ideas like these send them in an email.

   -Chas

-- 
Charles Dawson
Senior Engineering Manager
NC-Verilog Team
Cadence Design Systems, Inc.
270 Billerica Road
Chelmsford, MA  01824
(978) 262 - 6273
chas@cadence.com