Re: [Qemu-ppc] [Qemu-devel] [PATCH 00/34] tcg, target/ppc vector improvements

[Mark Cave-Ayland]

On 18/12/2018 15:17, Richard Henderson wrote:

> On 12/18/18 7:05 AM, Mark Cave-Ayland wrote:
>> On 18/12/2018 09:49, Mark Cave-Ayland wrote:
>>
>>> Following on from this, the next patch "target/ppc: convert vsplt[bhw] to 
>>> use vector
>>> operations" causes corruption of the OS X splash screen
>>> (https://www.ilande.co.uk/tmp/qemu/badapple2.png) in a way that suggests 
>>> there may be
>>> an endian issue.
>>
>> Changing "#ifndef HOST_WORDS_BIGENDIAN" to "#ifdef HOST_WORDS_BIGENDIAN" in 
>> this
>> patch helps a lot, but something still isn't quite right:
>> https://www.ilande.co.uk/tmp/qemu/badapple3.png.
> 
> I can't figure out what the host+guest endian rules for ppc_avr_t are at all.
> 
> Certainly there appear to be bugs wrt vscr and which end of the register we
> pull the value.  On the tcg side we take host endianness into account, and on
> the gdb side we always use u32[3].

That seems wrong to me. Given that the ppc_avr_t is a union then I'd expect it 
to be
in host order? Certainly in the VMX helper macros I've looked at, the members 
are set
directly with no byte swapping.


ATB,

Mark.