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From: Nathan Froyd <froydnj@codesourcery.com>
To: Peter W Schultz <kaedenn@gmail.com>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] Implementing atomic SWP in qemu-arm
Date: Wed, 18 Aug 2010 12:37:19 -0700	[thread overview]
Message-ID: <20100818193719.GW25394@codesourcery.com> (raw)
In-Reply-To: <AANLkTinyhZUyXpj1O6hqEZSMmsRzgvO1YfCGH6wRjYOK@mail.gmail.com>

On Wed, Aug 18, 2010 at 12:15:09PM -0700, Peter W Schultz wrote:
> How would I go about modifying the qemu source to implement SWP
> atomically? I have been studying the source for a few days now, and I
> am at a loss as to what all needs to be done.

You should look at how the load/store-exclusive instructions work and
see if you can use a similar mechanism.  It should be fairly
straightforward.

> I feel it would be most desirable to add a TCG_SWAP instruction that
> is guaranteed to be an atomic compare-and-swap, and implement that as
> needed.

I believe there was an thread several months ago discussing doing this
or something similar and it was decided that mechanism was not the way
to go.

-Nathan

      reply	other threads:[~2010-08-18 19:37 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-08-18 19:15 [Qemu-devel] Implementing atomic SWP in qemu-arm Peter W Schultz
2010-08-18 19:37 ` Nathan Froyd [this message]

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