From: BrianG <me@null.email>
Subject: Re: Should representation clauses be complete for each bit?
Date: Sun, 31 Jul 2011 11:02:04 -0400
Date: 2011-07-31T11:02:04-04:00 [thread overview]
Message-ID: <j13qpc$e54$3@dont-email.me> (raw)
In-Reply-To: <wccd3h3brm3.fsf@shell01.TheWorld.com>
On 07/21/2011 11:06 AM, Robert A Duff wrote:
> Georg Bauhaus<rm.dash-bauhaus@futureapps.de> writes:
>
>> More specifically, if the original example of "not all bits used and some
>> gaps between them" is unusual, is it so
>>
>> - when mapping to a set of hardware pins, say?
>
> Whenever I see documentation for such things, they have rectangular pictures
> showing what every bit means. They don't have implicit gaps. If there
> are any gaps, they are shown explicitly, as "must be zero" or "reserved
> for future hardware extensions" or whatever.
>
> My claim is that the Ada code interfacing to such a thing should be
> similarly explicit about the gaps.
>
> Otherwise, you end up with nasty bugs: one compiler just happens to
> set the gaps to zero, and you write to a file, and binary comparisons
> of those files work. Then you port to a different compiler, and it
> puts arbitrary junk in the gaps.
It doesn't have to be a different compiler, or even a different version
- this can happen with host/target. For instance, Windows and VxWorks
always seem to be exact opposites on these kind of things. Makes coding
standards and such rather important.
BrianG
000
@gmail.com
[test email, trying to re-set-up account]
next prev parent reply other threads:[~2011-07-31 15:02 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-20 10:34 Should representation clauses be complete for each bit? okellogg
2011-07-20 14:51 ` Robert A Duff
2011-07-20 15:24 ` Georg Bauhaus
2011-07-20 17:28 ` Robert A Duff
2011-07-21 7:37 ` Martin
2011-07-21 8:22 ` Simon Wright
2011-07-21 14:58 ` Robert A Duff
2011-07-23 0:13 ` Randy Brukardt
2011-07-27 14:12 ` okellogg
2011-07-28 0:03 ` Randy Brukardt
2011-07-21 9:43 ` Georg Bauhaus
2011-07-21 15:06 ` Robert A Duff
2011-07-31 15:02 ` BrianG [this message]
2011-07-21 21:11 ` Brian Drummond
2011-07-21 7:59 ` Stephen Leake
2011-07-20 15:29 ` okellogg
2011-07-20 16:24 ` Dmitry A. Kazakov
2011-07-20 16:58 ` okellogg
2011-07-20 19:38 ` Dmitry A. Kazakov
2011-07-20 17:27 ` Robert A Duff
2011-07-20 19:14 ` okellogg
2011-07-20 20:13 ` J-P. Rosen
2011-07-20 21:23 ` Robert A Duff
2011-07-20 21:21 ` Robert A Duff
2011-07-21 8:02 ` Stephen Leake
2011-07-21 8:00 ` Stephen Leake
2011-07-21 7:36 ` Martin
2011-07-22 23:50 ` Randy Brukardt
2011-07-23 2:16 ` tmoran
2011-07-23 15:12 ` Robert A Duff
2011-07-26 21:10 ` Randy Brukardt
2011-07-23 0:01 ` Randy Brukardt
-- strict thread matches above, loose matches on Subject: below --
1998-04-17 0:00 Should Representation Clauses " Marin David Condic, 561.796.8997, M/S 731-96
[not found] <3533C3C5.3F25CB91@cacd.rockwell.com>
1998-04-16 0:00 ` Stephen Leake
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