RFR (M): 8036767 PPC64: Support for little endian execution model

[Alexander Smundak]

I was concerned by the term 'variant', which might suggest that the applications
built for PPC64 and PPC64LE are binary compatible. They are not.

On Wed, Mar 12, 2014 at 3:55 PM, David Holmes <david.holmes at oracle.com> wrote:
> On 12/03/2014 9:19 AM, Alexander Smundak wrote:
>>
>> On Tue, Mar 11, 2014 at 3:51 PM, Vladimir Kozlov
>> <vladimir.kozlov at oracle.com> wrote:
>>>
>>> It would only help if you could do cross compilation to have both build
>>> variants at the same place. Currently you can only build le variant on
>>> ppc64le machine and vice versa. That is why, I think, David asked if we
>>> can
>>> control what variant to build.
>>
>> Just to clarify the situation a bit: ppc64le is not a variant of ppc64.
>> That is,
>> an application compiled for the little-endian PowerPC64 does not "just
>> run" on
>> the big-endian PowerPC64 (albeit OS can have such feature, similar to the
>> ability of the Linux running on x86_64 CPU to run 32-bit x86
>> applications).
>> So ppc64le is a different architecture from ppc64.
>
>
> I disagree with that classification for "architecture" and it seems at odds
> with the literature which describes the endian-ness selection as a "mode".
>
> David
> -----
>
>
>>> I would like to see the changes based on Volker suggestion. We can
>>> compare
>>> them and decide which way to go.
>>
>> Volker has the detailed suggestion here:
>>
>> http://mail.openjdk.java.net/pipermail/ppc-aix-port-dev/2014-March/001790.html
>> and it involves additional Make variable and if statements in the
>> platform makefile
>>   where they are not supposed to be present.
>>
>