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From: Alex Williamson <alex.williamson@redhat.com>
To: Richard Henderson <rth@twiddle.net>
Cc: lersek@redhat.com, qemu-devel@nongnu.org, qemu-stable@nongnu.org
Subject: Re: [Qemu-devel] [PATCH v2] exec: Fix non-power-of-2 sized accesses
Date: Fri, 16 Aug 2013 09:37:33 -0600	[thread overview]
Message-ID: <1376667453.28796.0.camel@ul30vt.home> (raw)
In-Reply-To: <520E44CA.6050205@twiddle.net>

On Fri, 2013-08-16 at 08:27 -0700, Richard Henderson wrote:
> On 08/16/2013 05:50 AM, Alex Williamson wrote:
> > +    /* Size must be a power of 2 */
> > +    if (l & (l - 1)) {
> > +        while (l & (access_size_max - 1)) {
> > +            access_size_max >>= 1;
> > +        }
> > +    }
> > +
> 
> Why the loop at all?  x & -x extracts the lsb of x.

l = 5, we want 4, not 1.  Thanks,

Alex

  reply	other threads:[~2013-08-16 15:37 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-08-16 12:50 [Qemu-devel] [PATCH v2] exec: Fix non-power-of-2 sized accesses Alex Williamson
2013-08-16 13:37 ` Laszlo Ersek
2013-08-16 15:27 ` Richard Henderson
2013-08-16 15:37   ` Alex Williamson [this message]
2013-08-16 15:43     ` Alex Williamson
2013-08-16 15:46       ` Alex Williamson
2013-08-16 19:46     ` Richard Henderson
2013-08-16 20:04       ` Eric Blake

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