From: malc <av1474@comtv.ru>
To: Richard Henderson <rth@twiddle.net>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] TCG sar UB (fwd)
Date: Wed, 7 Sep 2011 20:04:41 +0400 (MSD) [thread overview]
Message-ID: <alpine.LNX.2.00.1109072002470.15533@linmac> (raw)
In-Reply-To: <alpine.LNX.2.00.1109040632250.1599@linmac>
On Sun, 4 Sep 2011, malc wrote:
> On Sun, 4 Sep 2011, Richard Henderson wrote:
>
> > On 09/03/2011 03:47 PM, malc wrote:
> > > Doesn't make much sense to me, guest clearly asked for 0 and not -1,
> > > besides -1 violates TCG's sar constraints and PPC obliges by emiting
> > > illegal instruction in this case.
> >
> > The shift that the guest asked for was completely folded away.
> >
> > The -1 comes from gen_shift_rm_T1 in the computation of the new
> > flags value. This could instead be moved inside the test for != 0,
> > which is the only place that value is actually used anyway.
> >
> > Try this. Lightly tested.
>
> Now i either get hosts illegal instruction or (with logging enabled) a
> guest kenrnel panic.
Actually i was habitually testing i386-softmmu/qemu.. And after trying
the "properly" named binary things do work.. Want to provide a comment
so i can push that?
[..snip..]
--
mailto:av1474@comtv.ru
next prev parent reply other threads:[~2011-09-07 16:05 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <alpine.LNX.2.00.1109031417430.1511@linmac>
2011-09-04 2:27 ` [Qemu-devel] TCG sar UB (fwd) Richard Henderson
2011-09-04 2:33 ` malc
2011-09-06 14:48 ` Richard Henderson
2011-09-06 15:20 ` malc
2011-09-07 5:19 ` Richard Henderson
2011-09-07 16:04 ` malc [this message]
2011-09-08 8:23 ` [Qemu-devel] [PATCH] target-i386: Compute all flag data inside %cl != 0 test Richard Henderson
2011-09-08 14:12 ` malc
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