Re: errata/282: signing

From: Shalom.Bresticker@freescale.com
Date: Tue May 04 2004 - 20:30:00 PDT

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    The following reply was made to PR errata/282; it has been noted by GNATS.

    From: Shalom.Bresticker@freescale.com
    To: Bruce LaVigne <bruce@hp.com>
    Cc: etf-bugs@boyd.com
    Subject: Re: errata/282: signing
    Date: Wed, 5 May 2004 06:45:32 +0300 (IDT)

     Bruce,
     
     Unfortunately, the LRM is not clear enough, which is what we are trying to
     fix in the discussions on the sign-related errata.
     
     However, you would definitely not sign-extend in this case, because neither
     a nor b is signed, they are both unsigned. Unsigned entities are zero-extended,
     not sign-extended.
     
     Shalom
     
     
     On Tue, 4 May 2004, Bruce LaVigne wrote:
     
    > I appologize for not following this width/sign-extension discussion fully,
    > but from a user point of view, I hope that the LRM clearly spells out which of
    > these behaviours will occur, as this would be the first place I'd look to make
    > sure I got a desired result from simulators & synthesis tools - neither is the
    > "obvious" answer to me, and in fact, another possibility would be that in
    > widening b, you sign-extend to get 8'b11111100, which gives a final result
    > identical to what Shalom points out is the wrong answer!
     

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