From: Simon Clubley <clubley@remove_me.eisner.decus.org-Earth.UFP>
Subject: Re: Modified proposals for Ada-Comment
Date: Thu, 17 Jul 2014 21:15:14 +0000 (UTC)
Date: 2014-07-17T21:15:14+00:00 [thread overview]
Message-ID: <lq9ed2$cbt$1@dont-email.me> (raw)
In-Reply-To: c2dotiF8chiU1@mid.individual.net
On 2014-07-12, Niklas Holsti <niklas.holsti@tidorum.invalid> wrote:
>
> Might you include in this question also whether increasing the size of
> an atomic object using a 'Size clause means that the atomic access
> should apply to all the bits included in 'Size, and not just to the bits
> included in the declared components of the object?
>
The response (from Tucker Taft) I got to your 'Size question was this:
My original question as submitted:
|| As a related question, when C.6(15) does apply, does it also apply to
|| all the bits included by 'Size when 'Size has been used to increase
|| the size of the atomic object (say from 5 bits to 32 bits) ?
||
The response:
|
|The definition of 'Size on an elementary object is that it refers to the
|number of bits normally read/written, as specified in 13.1(7/2):
|
| "The representation of an object consists of a certain number of bits
| (the size of the object). For an object of an elementary type, these are
| the bits that are normally read or updated by the machine code when
| loading, storing, or operating-on the value of the object...."
|
|For a non-atomic composite object, extra bits might not be loaded/stored,
|again quoting from that same paragraph:
|
| "... For a composite object, padding bits might not be read or updated in
| any given composite operation, depending on the implementation."
|
|For an atomic composite object, although it is not stated explicitly, the
|implication is that the 'Size of an atomic object determines the number of
|bits read/written indivisibly (e.g. see C.6(11/4)).
On a related matter, the responses to the C.6(15) question about if
Atomic on a record applies to it's components, are in the general
direction of no it doesn't.
Simon.
--
Simon Clubley, clubley@remove_me.eisner.decus.org-Earth.UFP
Microsoft: Bringing you 1980s technology to a 21st century world
prev parent reply other threads:[~2014-07-17 21:15 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-12 18:45 Modified proposals for Ada-Comment Simon Clubley
2014-07-12 21:00 ` Simon Wright
2014-07-12 21:24 ` Simon Clubley
2014-07-12 21:50 ` Niklas Holsti
2014-07-12 22:19 ` Simon Clubley
2014-07-13 0:06 ` Simon Clubley
2014-07-17 21:15 ` Simon Clubley [this message]
replies disabled
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox