From: Steven Sharp (sharp@cadence.com)
Date: Tue Jul 02 2002 - 13:32:49 PDT
Precedence: bulk
>Actually, this doesn't seem sufficient when the base expression
>is actually constant, i.e.
>
> reg [31:0] vector;
>
> vector[31-:8] // both base and width are constant, thus vpiConstantSelect
== true,
> // but this is not a regular part-select
I think it is time to let Charles answer this, instead of me trying
to recall what he said. Either vpiConstantSelect was supposed to be
false in this case (making it a poor choice of names for the property),
or VPI was supposed to convert the constant case into an equivalent
non-indexed part select and return the range values for that, or
something else that I didn't understand at the time.
>Given the counterexample above, it would seem a new property (properties??)
>of part selects is needed at the very least to determine whether a part select
>is an index part select, and which type of indexed part-select.
>
>Or, alternatively, entirely new VPI objects to represent +: and -: could be
>defined.
This may have been another situation where the extension was changed after
the PLI task force had dealt with it, and they didn't compensate for the
change. The original proposal didn't have two variations (though it had
other more serious problems).
Steven Sharp
sharp@cadence.com
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