Re: errata/608: mintypmax_expression usage

From: Eric Mahurin (eric_mahurin@yahoo.com)
Date: Sat Jul 31 2004 - 14:00:00 PDT

  • Next message: Shalom.Bresticker@freescale.com: "errata/554: PROPOSAL - A.2.6: function_declaration BNF bug for return type declarations"

    The following reply was made to PR errata/608; it has been noted by GNATS.

    From: Eric Mahurin <eric_mahurin@yahoo.com>
    To: Shalom.Bresticker@freescale.com, etf-bugs@boyd.com
    Cc:
    Subject: Re: errata/608: mintypmax_expression usage
    Date: Sat, 31 Jul 2004 14:00:18 -0700 (PDT)

     One problem I see is if you wanted to make a simulator
     that didn't default to min, typ, or max for delays,
     but instead effectively simulated a range of delays.
     For example:
     
     a = 1'b0;
     #1:2:3;
     a = 1'b1;
     
     You might want to treat this equivalent to:
     
     a = 1'b0;
     #1;
     a = 1'bX;
     #2; // time=3
     a = 1'b1;
     
     This way you would be simulating the entire delay
     range at once. I don't think min:typ:max would make
     any sense anywhere except delays if you wanted to do
     such a thing.
     
     Eric
     
     --- Shalom.Bresticker@freescale.com wrote:
     
    > Synthesis tools may not implement such a switch,
    > but there is nothing
    > inherent in the mintypmax feature which makes it
    > unusable in synthesis.
    >
    > The name "mintypmax" indicates its typical use,
    > the reason the feature was created in Verilog,
    > but once existing, it can be used for other
    > purposes as well.
    >
    > > There's usually a simulator switch to control
    > whether to pick up
    > > min, typ or max, with typ as the default. A
    > common use is explore
    > > the potential impact of the library cell delay
    > factors. (Mintypmax
    > > expressions have no meaning in synthesis.)
    >
    > Shalom
     
     
     
                     
     __________________________________
     Do you Yahoo!?
     Take Yahoo! Mail with you! Get it on your mobile phone.
     http://mobile.yahoo.com/maildemo
     

    This archive was generated by hypermail 2.1.4 : Sat Jul 31 2004 - 14:00:06 PDT and
    sponsored by Boyd Technology, Inc.