[FFmpeg-devel] [PATCH] Altivec split-radix FFT

Måns Rullgård mans
Tue Sep 15 22:27:26 CEST 2009


Loren Merritt <lorenm at u.washington.edu> writes:

> On Tue, 15 Sep 2009, M?ns Rullg?rd wrote:
>
>> Loren Merritt <lorenm at u.washington.edu> writes:
>>
>>> Fixed register names (untested).
>>> The manually unrolled list is ugly, but I can't find a gas equivalent
>>> to yasm's ability to expand macros in macro names.
>>
>> Can you elaborate on that?
>
> gas:
> DEFINE_REG 0
> DEFINE_REG 1
> [...]
>
> yasm:
> %assign i 0
> %rep 32
> DEFINE_REG i
> %assign i i+1
> %endrep

I can't think of a way to do that with gas.

>>> Didn't change .rodata. Is there some version-dependent define for that?
>>> Or same/another configure check?
>>
>> What is the problem with .rodata again?
>
> Apple calls it .const_data instead.

That would be easily solved with an ifdef or two.

> Remaining problems that I don't know how to solve:
> The only macro syntax that gas supports is named args. The only macro
> syntax that Apple as supports is numbered args. So a polyglot can't
> use macros at all.

So it's the same mess as on ARM.

> And Guillame said that Apple as doesn't have a string concatenation
> operator.
>
> Can we just not support Apple? That would make it all simple.

I won't complain.  If there's anyone left running macos on ppc, they
can use David's script to convert the syntax.

-- 
M?ns Rullg?rd
mans at mansr.com



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