From: Niklas Holsti <niklas.holsti@tidorum.invalid>
Subject: Re: GNAT 4.4.5 Record Bit_Order Endian issues
Date: Fri, 18 Jan 2013 17:28:09 +0200
Date: 2013-01-18T17:28:09+02:00 [thread overview]
Message-ID: <alt809FcfavU1@mid.individual.net> (raw)
In-Reply-To: <kdap96$ic2$1@dont-email.me>
On 13-01-18 08:15 , J-P. Rosen wrote:
> Regarding the use of "at": you can always use 0 and number the bits
> starting from the beginning of the record (and bit numbers are not
> limited to 31).
Except that if you use the non-default bit order, then the bit numbers
are limited by the number of bits in the "largest machine scalar", per
RM 13.5.1(10.2/2), except in a special case (10.3/2).
Which means, for a portable program where you don't know what the
default bit order will be on some platform, nor know what size scalars
that platform has, you had best limit the bit numbers to a very
conservative range.
I have stopped using record representation clauses in portable Ada
programs and prefer to access bit-fields by shifting and masking. Sorry
to say.
--
Niklas Holsti
Tidorum Ltd
niklas holsti tidorum fi
. @ .
next prev parent reply other threads:[~2013-01-18 15:28 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-14 17:43 GNAT 4.4.5 Record Bit_Order Endian issues awdorrin
2013-01-15 0:38 ` Randy Brukardt
2013-01-15 1:57 ` Adam Beneschan
2013-01-15 16:57 ` AdaMagica
2013-01-15 22:24 ` Stephen Leake
2013-01-16 10:44 ` Simon Wright
2013-01-16 19:00 ` AdaMagica
2013-01-16 21:34 ` Simon Wright
2013-01-16 23:14 ` Randy Brukardt
2013-01-17 3:49 ` Stephen Leake
2013-01-17 15:32 ` awdorrin
2013-01-18 9:49 ` Stephen Leake
2013-01-18 13:04 ` Robert A Duff
2013-01-19 1:43 ` Stephen Leake
2013-01-19 12:48 ` AdaMagica
2013-01-22 0:14 ` Randy Brukardt
2013-01-17 17:28 ` Simon Wright
2013-01-18 9:56 ` Stephen Leake
2013-01-17 18:04 ` awdorrin
2013-01-17 19:50 ` awdorrin
2013-01-18 9:58 ` Stephen Leake
2013-01-17 20:58 ` Simon Wright
2013-01-17 21:29 ` awdorrin
2013-01-17 22:16 ` awdorrin
2013-01-18 6:15 ` J-P. Rosen
2013-01-18 15:28 ` Niklas Holsti [this message]
2013-01-18 9:37 ` Stephen Leake
2013-01-18 12:24 ` awdorrin
2013-01-18 15:11 ` awdorrin
2013-01-19 1:48 ` Stephen Leake
2013-01-18 17:19 ` Simon Wright
2013-01-22 9:49 ` quinot
2013-01-28 13:39 ` quinot
-- strict thread matches above, loose matches on Subject: below --
2013-01-22 3:21 Stephen Leake
2013-01-22 5:14 ` Jeffrey Carter
2013-01-23 1:29 ` Stephen Leake
2013-01-22 22:40 ` Randy Brukardt
2013-01-23 1:38 ` Stephen Leake
2013-01-23 10:58 ` Simon Wright
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