From: David Howells <dhowells@redhat.com>
To: Michael Cree <mcree@orcon.net.nz>
Cc: dhowells@redhat.com, linux-alpha@vger.kernel.org,
linux-kernel@vger.kernel.org, rth@twiddle.net,
ink@jurassic.park.msu.ru
Subject: Re: Alpha: suspicious compiler warning in entry.S
Date: Fri, 30 Oct 2009 13:16:59 +0000 [thread overview]
Message-ID: <5962.1256908619@redhat.com> (raw)
In-Reply-To: <4AE7ECC2.8050202@orcon.net.nz>
Michael Cree <mcree@orcon.net.nz> wrote:
> On the assumption that it is important to include the TIF_NOTIFY_RESUME bit
> one might be tempted to modify the code to:
>
> lda $2, _TIF_WORK_MASK
> and $5, $2, $2
>
> but this is time critical code. I am wondering whether it might be better
> to rearrange the bits in the thread information flags so that _TIF_WORK_MASK
> has a value less than 255 and the single instruction to perform an and
> operation can be maintained.
Unless the LDA can be interleaved around some memory accesses, then yes,
compressing _TIF_WORK_MASK would be good.
David
prev parent reply other threads:[~2009-10-30 13:16 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-28 7:03 Alpha: suspicious compiler warning in entry.S Michael Cree
2009-10-28 23:13 ` Richard Henderson
2009-10-31 2:33 ` [PATCH] Alpha: Rearrange thread info flags fixing two regressions Michael Cree
2009-12-01 4:06 ` Matt Turner
2009-12-01 12:31 ` Christoph Hellwig
2009-12-01 15:58 ` Matt Turner
2009-10-30 13:16 ` David Howells [this message]
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