Re: [Qemu-devel] [HelenOS-devel] [sparc64] Miscomputed minimum of a group of numbers in sparc64 emulation

[Jakub Jermar]

On 1.7.2011 16:24, Laurent Desnogues wrote:
> On Fri, Jul 1, 2011 at 4:11 PM, Jakub Jermar <address@hidden> 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