RE: 4 State Logic Proposals

Hi Russ,
>
>> I also don't think (but with less fervency) that sending X's or Z's 
>> should cause a run time error.
>
>I'd like to understand why you do not want this to be an error.

I can see a situation where there'd be a simulation model -- used mostly
for simulation -- which needs to be ported (hopefully we can deprecate
that work "port") to emulation/hw acceleration.

Say this model is sending and receiving 4-state values ('X's and 'Z's) in
many places.

To port to emulation, since SCEMI 2.0 allows the DPI 4-state data types to
be used,
is an exercise in going through the application code and either commenting
out, changing, or ifdef-ing around the offending code that sends 'X's and
'Z's.
(Let's confine this case to the C->HDL half of the problem for now).

So, the poor sap responsible for effecting the changes runs the code through
the
IFLC, then emulates, and gets 200 warnings before the sim crashes due to
coerced
values causing aberrant behavior.

Upon looking at the warnings, it is noticed that 190 of them are for 4-state
writes to sections of the DUT that are "turned off" for this particular
simulation.
Thus, only a few sections of code needed to be changed: the rest can send
coerced
values all day long to the quiescent part of the DUT and it will not affect
the whole
simulation and the expected result.

So you see where a fatal error generated from every 4-state write to the HDL
side would
get in the way of getting this case up and running?


russ


---------------------------------------
---    Russ Vreeland (949)926-6143  ---
---    vreeland@broadcom.com        ---
---    Senior Principal Engineer    ---
---    Broadcom Corporation         ---
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