From: Jakub Jermar <jakub@jermar.eu>
To: Laurent Desnogues <laurent.desnogues@gmail.com>
Cc: HelenOS development mailing list <helenos-devel@lists.modry.cz>,
qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [HelenOS-devel] [sparc64] Miscomputed minimum of a group of numbers in sparc64 emulation
Date: Fri, 01 Jul 2011 16:28:32 +0200 [thread overview]
Message-ID: <4E0DD990.8070708@jermar.eu> (raw)
In-Reply-To: <BANLkTi=f1tbZSx=tp9OUAOML+mFCWXmW2A@mail.gmail.com>
On 1.7.2011 16:24, Laurent Desnogues wrote:
> On Fri, Jul 1, 2011 at 4:11 PM, Jakub Jermar <jakub@jermar.eu> wrote:
> [...]
>> Actually, the testcase can be further reduced into:
>>
>> .global _start
>>
>> .text
>>
>> .space 0x20
>>
>> _start:
>> set 110393, %i1
>> set 0x40, %i2
>>
>> cmp %i1, %i2
>> udivx %g0, 1, %g0
>> movgu %xcc, %i2, %i1
>> cmp %i1, 512
>> bgu %xcc, 0f
>> nop
>>
>> succ:
>> ta 0
>>
>> fail:
>> 0:
>> ta 1
>>
>> The presence of the `udivx` instruction seems to be essential. Even
>> though it has no effect on the computation, removing it will make the
>> testcase non-reproducible.
>
> Could you try to replace udivx with sdivx? It looks wrong too.
Yeah, `sdivx` behaves the same wrt. the testcase.
Jakub
next prev parent reply other threads:[~2011-07-01 14:28 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-30 21:12 [Qemu-devel] [sparc64] Miscomputed minimum of a group of numbers in sparc64 emulation Jakub Jermar
2011-07-01 9:15 ` [Qemu-devel] [HelenOS-devel] " Artyom Tarasenko
2011-07-01 9:36 ` Jakub Jermar
2011-07-01 10:41 ` Artyom Tarasenko
2011-07-01 12:57 ` Jakub Jermar
2011-07-01 14:11 ` Jakub Jermar
2011-07-01 14:24 ` Laurent Desnogues
2011-07-01 14:28 ` Jakub Jermar [this message]
2011-07-01 15:08 ` Artyom Tarasenko
2011-07-01 14:15 ` Laurent Desnogues
2011-07-01 14:21 ` Jakub Jermar
2011-07-01 15:03 ` Artyom Tarasenko
2011-07-01 15:20 ` Laurent Desnogues
2011-07-01 15:53 ` Artyom Tarasenko
2011-07-01 16:14 ` Artyom Tarasenko
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