[U-Boot] Where is the GPR30 register in PowerPC arch as GOT pointer of C code documented?

[Gao Ya'nan]

Thanks for your tip and sorry for my ambiguit question.

When I read the relocate_code function in cpu/mpc8xx/start.S, I found
the code below:

=============================================================================
512         sub     r15, r10, r4
513
514         /* First our own GOT */
515         add     r14, r14, r15
516         /* then the one used by the C code */
517         add     r30, r30, r15
=============================================================================

And I checked the dis-assemble code, and R30 was used as a pointer,
but which specification documentes this usage or it is just GCC's
flavor?

2009/8/12 Kumar Gala <galak at kernel.crashing.org>:
>
> On Aug 12, 2009, at 8:46 AM, Gao Ya'nan wrote:
>
>> I find nothing about this in (E)ABI specification(perhaps some old),
>> so, where is it?
>
> You want the ABI that is available here:
>
> http://refspecs.freestandards.org/elf/elfspec_ppc.pdf
>
> The EABI is just extensions on top of it.
>
> - k
>