[Pixman] Help with sending patch

Lennart Sorensen lsorense at csclub.uwaterloo.ca
Fri May 22 12:39:05 PDT 2015


On Fri, May 22, 2015 at 04:07:03PM -0300, Fernando Seiti Furusato wrote:
> Hi Lennart.
> 
> Your questions really got me thinking. But I made some researching.
> 
> On 05/22/2015 02:54 PM, Lennart Sorensen wrote:
> >Isn't altivec always big endian?  If so, that would make running altivec
> >code while in little endian mode interesting.
> I believe that depends mostly on the implementation.
> The implications of endianness differences for the instructions themselves can
> be checked out on Power ABI Specification[1].
> >
> >I was under the impression that ppc64le used vsx instead of altivec.
> Afaik, vsx is actually an extension to SIMD processing for POWER. It was
> introduced with POWER7 machines.
> 
> Thanks!
> 
> [1] https://www-03.ibm.com/technologyconnect/tgcm/TGCMFileServlet.wss/ABI64BitOpenPOWER_21July2014_pub%283%29.pdf?id=B81AEC1A37F5DAF185257C3E004E8845&linkid=1n0000&c_t=c9xw7v5dzsj7gt1ifgf4cjbcnskqptmr

That seems to require registration. :)

This presentation seemed to indicate that at least there are some biases
towards big endian in the vector instructions:

http://llvm.org/devmtg/2014-10/Slides/Schmidt-SupportingVectorProgramming.pdf

-- 
Len Sorensen


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