Re: [Qemu-devel] Call for testing QEMU aarch64-linux-user emulation

2014-03-06 Thread Alex Bennée

Janne Grunau  writes:

> On 2014-02-25 15:54:37 +, Alex Bennée wrote:
>>

>> Have you got the log file "unsupported" line? I seem to recall you did
>> ping me but maybe it was just on IRC? I just want to make sure I
>> do the right ones. I'm working on this now.
>
> We spoke on irc about it. a quick test commenting unsupported
> instructions out revealed that rshrn/2, sqrshrun and shrn/2 are
> the only NEON instructions used in libav still missing support
> in qemu master. Unsoppurted lines from qemu master 0459650d94d1
> below.
>
> target-arm/translate-a64.c:6884: unsupported instruction encoding 0x0f0a8e10 
> at pc=008632c8
> target-arm/translate-a64.c:6884: unsupported instruction encoding 0x2f0b8f9c 
> at pc=00865764
> target-arm/translate-a64.c:6884: unsupported instruction encoding 0x0f0a8610 
> at pc=00863afc

I've just pushed support for the various shrn opcodes to:

https://github.com/stsquad/qemu/tree/ajb-a64-working

I suspect if libav uses them heavily there could be some optimisation
to be made as the narrow operations make heavy use of helpers to do the
saturation stuff.

-- 
Alex Bennée


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Re: [Qemu-devel] Call for testing QEMU aarch64-linux-user emulation

2014-03-06 Thread Janne Grunau
On 2014-03-06 11:40:47 +, Alex Bennée wrote:
> 
> Janne Grunau  writes:
> 
> > On 2014-02-25 15:54:37 +, Alex Bennée wrote:
> >>
> 
> >> Have you got the log file "unsupported" line? I seem to recall you did
> >> ping me but maybe it was just on IRC? I just want to make sure I
> >> do the right ones. I'm working on this now.
> >
> > We spoke on irc about it. a quick test commenting unsupported
> > instructions out revealed that rshrn/2, sqrshrun and shrn/2 are
> > the only NEON instructions used in libav still missing support
> > in qemu master. Unsoppurted lines from qemu master 0459650d94d1
> > below.
> >
> > target-arm/translate-a64.c:6884: unsupported instruction encoding 
> > 0x0f0a8e10 at pc=008632c8
> > target-arm/translate-a64.c:6884: unsupported instruction encoding 
> > 0x2f0b8f9c at pc=00865764
> > target-arm/translate-a64.c:6884: unsupported instruction encoding 
> > 0x0f0a8610 at pc=00863afc
> 
> I've just pushed support for the various shrn opcodes to:
> 
> https://github.com/stsquad/qemu/tree/ajb-a64-working

Thanks, just testing it and it seems to work as expected.

> I suspect if libav uses them heavily there could be some optimisation
> to be made as the narrow operations make heavy use of helpers to do the
> saturation stuff.

The saturating shift is not that heavily used and I don't care much as
long as qemu is an order of magnitude faster than ARM's foundation model
and much easier to handle than Apple hardware.

Janne

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