RE: [sv-bc] A question about type casting

Dave,

I agree that it is important for implicit and explicit cast
functionality to match. We will get a lot of SV users shaking
their heads in dismay if this isn't done.

Question: Do you intend to file another change request regarding
task/function argument passing to resolve issue SV-BC-177?

Regards
Doug

> -----Original Message-----
> From: owner-sv-bc@server.eda.org
> [mailto:owner-sv-bc@server.eda.org] On Behalf Of Dave Rich
> Sent: Friday, March 19, 2004 1:01 PM
> To: pgraham@cadence.com
> Cc: jacob.katz@intel.com; sv-bc@server.eda.org
> Subject: Re: [sv-bc] A question about type casting
>
>
> I will file an erratum to change the assignment compatibility
> rules for
> unpacked arrays back to the way they were in SV3.1. The reason it was
> changed in the first place was because the was a conflict with the
> definition of task/function argument passing. See SV-BC-177.
> We should
> have changed the definition of task/function argument passing
> to match
> the existing assignment compatibility rules.
>
> I think it is important that an implicit cast match the
> functionality of
> its explicit cast.
>
> Dave
>
>
> Paul Graham wrote:
>
> >> According to the current definition of casting in 3.16, the
> >>assignment in the mail below is *not* legal. This is
> because the total
> >>number of bits in tx and ty is different, while explicit casting
> >>currently requires it to be equal.
> >>
> >>
> >
> >Bit-stream casting is quite different from the kind of word-level
> >assignments I was describing. Word-level assignments require the
> >number of words (unpacked elements) be the same in the source and
> >target, but the number of bits per word can change, and the total
> >number of bits in source and target can be different. Bit-stream
> >casting loses information about the number of words in the
> source, but
> >preserves the number of bits. I can see a use for both kinds of
> >data conversions.
> >
> >So yes, it looks you can have unpacked array types which are
> assignment
> >compatible but not cast compatible!
> >
> >Paul
> >
> >
> >
> >
>
> --
> --
> David.Rich@Synopsys.com
> Technical Marketing Consultant and/or
> Principal Product Engineer
> http://www.SystemVerilog.org
> tele: 650-584-4026
> cell: 510-589-2625
>
>
>
Received on Fri Mar 19 13:18:53 2004