RE: errata/562: Need to have a vpiTimeConst in the vpi_user.h file

From: Jim Vellenga (vellenga@cadence.com)
Date: Thu Jul 01 2004 - 06:20:00 PDT

  • Next message: Shalom.Bresticker@freescale.com: "RE: errata/562: Need to have a vpiTimeConst in the vpi_user.h file"

    The following reply was made to PR errata/562; it has been noted by GNATS.

    From: "Jim Vellenga" <vellenga@cadence.com>
    To: <Shalom.Bresticker@freescale.com>, <ptf-bugs@boyd.com>
    Cc:
    Subject: RE: errata/562: Need to have a vpiTimeConst in the vpi_user.h file
    Date: Thu, 1 Jul 2004 09:17:16 -0400

     I can't comment on the _need_ to distinguish the types
     of untyped parameters. But I do observe that
     vpiConstType was applied to parameters already
     in the 1364-1995 standard, before the new types were
     available. So if you accept the antecedent of
     maintaining backward compatibility when possible,
     then it looks to me that the only choice
     available back then was reporting the style of lexical
     representation of the constant on the right-hand
     side, and we ought to continue to do the same.
     
     As to what the vpiConstType is for Q, my tests with
     our own tool suggested that the type of an untyped
     parameter with an expr on the right-hand side that
     is not a constant is either vpiDecConst or
     vpiRealConst. So by that logic, the vpiConstType
     of Q would be a vpiDecConst.
     
     The alternative, of course, is to do yet another
     exception when the right-hand side is just a typed
     parameter. In that case, we could specifically say
     that Q should have the same vpiConstType as P.
     
     I would tend to go with the former because
     
     a) it probably doesn't matter to our users (see
     Shalom's first point), and
     
     b) it (at least conceptually) requires one less
     branch in the VPI code.
     
     Regards,
     Jim V.
     
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     Engineering Director (FAX) 978-262-6636
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