qemu-devel
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Qemu-devel] [PATCH] ppc32 guests: fix computation of XER.{CA, OV} i


From: J. Mayer
Subject: Re: [Qemu-devel] [PATCH] ppc32 guests: fix computation of XER.{CA, OV} in addme, subfme, mullwo
Date: Thu, 19 Jun 2008 00:09:10 +0200

On Wed, 2008-06-18 at 23:39 +0200, Julian Seward wrote:
> On Wednesday 18 June 2008 23:32, J. Mayer wrote:
> > Looking at the (relativelly) recent changes in this code, I can see that
> > I did an optimization that seems correct at first sight but... 
> > [ .. big patch deleted .. ]
> > Do you feel like this patch is buggy ?
> 
> Why don't you just commit the patch I sent?  It's shorter, it
> fixes the problem I reported and it does not cause any regressions.

it's ugly, obfuscated code, adding useless temporary variables and tests
that used not to be needed to achieve the same computation (where we
want the code to be fast and would like to remove all tests in flags
computations...).
Furthermore, it's inconsistent as more operations use similar code then
would need to be patched too if those one are false.
Then, I got numerous test results which gives the correct result with
the same arguments you use, running qemu on different hosts (x86, x86_64
and PPC32/64), then I must find time to redo all those tests to get
convinced it's now broken, find what did broke it, then rollback the
changes that broke this code.

-- 
J. Mayer <address@hidden>
Never organized





reply via email to

[Prev in Thread] Current Thread [Next in Thread]