From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Subject: Re: GNAT 4.8 atomic access to 64-bit objects
Date: Fri, 15 Nov 2013 09:44:41 +0100
Date: 2013-11-15T09:44:41+01:00 [thread overview]
Message-ID: <17hrkmg61tzsa.10xsgmupjcz79$.dlg@40tude.net> (raw)
In-Reply-To: 87k3gahgdp.fsf@ludovic-brenta.org
On Thu, 14 Nov 2013 21:34:26 +0100, Ludovic Brenta wrote:
> "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> writes:
>> The following does not compile anymore for 32-bit Linux targets, e.g. under
>> Debian:
>>
>> procedure Test is
>> type T is mod 2**64;
>> X : T;
>> pragma Atomic (X); -- Error
>> begin
>> null;
>> end Test;
>>
>> The above seems no more legal, because the compiler does not support
>> atomic access to X.
>>
>> Is there a way to change this without machine code insertions?
>
> Even with machine code insertions, I fail to see how a 32-bit processor
> can accept 64-bit integers as atomic.
movq ?
(the target is not an i386)
> I'd suggest you use 64-bit floating-point registers instead; i386
> processors have them, I think. That has been a useful trick for a
> decade or so :)
Using unchecked union or unchecked conversion?
--
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de
next prev parent reply other threads:[~2013-11-15 8:44 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-14 15:57 GNAT 4.8 atomic access to 64-bit objects Dmitry A. Kazakov
2013-11-14 20:34 ` Ludovic Brenta
2013-11-15 8:44 ` Dmitry A. Kazakov [this message]
2013-11-15 19:25 ` Georg Bauhaus
2013-11-15 21:33 ` Dmitry A. Kazakov
2013-11-16 10:08 ` Georg Bauhaus
2013-11-16 12:02 ` Dmitry A. Kazakov
2013-11-15 19:08 ` Stefan.Lucks
2013-11-15 21:19 ` Dmitry A. Kazakov
2013-11-22 0:30 ` Randy Brukardt
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