From: dennison@telepath.com
Subject: Re: Boolean Representation
Date: 1998/09/25
Date: 1998-09-25T00:00:00+00:00 [thread overview]
Message-ID: <6ug5l7$tsb$1@nnrp1.dejanews.com> (raw)
In-Reply-To: yecogs5gidf.fsf@king.cts.com
In article <yecogs5gidf.fsf@king.cts.com>,
Keith Thompson <kst@king.cts.com> wrote:
> dennison@telepath.com writes:
>
> > In article <6udkcj$87j$1@nnrp1.dejanews.com>,
> [...]
> > I believe the only guarantee you get is that the value of True is larger
than
> > the value of False.
>
> I don't believe even that much is guaranteed. A compiler I worked on
> used, for some targets, the representation (False => 0, True => -1)
> (i.e., a literal True value was represented with all bits set to 1
> (2's-complement) rather than just the last bit set to 1). This made
> tests and logical operations more efficient, at the expense of some
> extra code for Boolean'Pos, Boolean'Val, "<", ">", etc.
I suspect their claim would be: (False => 0, True => 2**32 - 1).
--
T.E.D.
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next prev parent reply other threads:[~1998-09-25 0:00 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
1998-09-24 0:00 Boolean Representation matthew_snyder
1998-09-24 0:00 ` dennison
1998-09-24 0:00 ` Keith Thompson
1998-09-25 0:00 ` dennison [this message]
1998-09-25 0:00 ` Keith Thompson
1998-09-26 0:00 ` Tucker Taft
1998-09-26 0:00 ` Keith Thompson
1998-09-27 0:00 ` null pointer representation (was: Boolean Representation) Arthur Evans Jr
1998-09-27 0:00 ` Keith Thompson
1998-09-28 0:00 ` dewarr
1998-09-28 0:00 ` Lieven Marchand
1998-09-28 0:00 ` Keith Thompson
1998-09-28 0:00 ` dewarr
1998-09-30 0:00 ` Keith Thompson
1998-10-02 0:00 ` Robert I. Eachus
1998-09-27 0:00 ` Boolean Representation dewarr
1998-09-27 0:00 ` dewarr
1998-09-24 0:00 ` dewarr
1998-09-24 0:00 ` matthew_snyder
1998-09-24 0:00 ` Tom Moran
1998-09-25 0:00 ` dewarr
1998-09-25 0:00 ` Tom Moran
1998-09-24 0:00 ` dennison
1998-09-25 0:00 ` Robert I. Eachus
1998-09-25 0:00 ` dewarr
1998-09-24 0:00 ` Samuel T. Harris
1998-09-25 0:00 ` dewarr
1998-09-27 0:00 ` Samuel T. Harris
1998-09-28 0:00 ` dewar
-- strict thread matches above, loose matches on Subject: below --
1998-09-24 0:00 matthew_snyder
1998-09-25 0:00 ` Tucker Taft
1998-09-25 0:00 ` dewarr
1998-09-25 0:00 ` dewarr
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