flac dev - Jan 2005 - A couple of points about flac 1.1.1 on ppc/linux/altivec

Luca Barbato <lu_zero@gentoo.org> writes:
> Josh Coalson wrote:
>>>Probably a version check could help.
>> how about this logic:
>> if cpu is ppc
>>   if as exists
>>     if as is apple version
>>       use as
>>     else if as is gnu version
>>       use as to assemble but src/libFLAC/ppc/gas directory
>>     else
>>       no asm
>>   else if gas exists
>>     use gas
>>   else
>>     no asm
>>
> Seems working to me
That looks fine to me as well. However, the best solution is something which
Luca suggested a few months ago, which is to use the functions defined in
altivec.h. These are C functions which map directly to Altivec machine
instructions. I am willing to help out, but I don't find the current
lpc_asm.s
very easy to follow, and my time is quite limited (my last patch to a free
software project took almost three months to get into decent shape!).

It would help to hear from Chris, I think.
>> could you also send me version strings for your versions of
>> as/gas for whatever combination of PPC,OS that you have?
Mine is the same as Luca's.

cheers,

John

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On Thu, 27 Jan 2005, John Steele Scott wrote:
> That looks fine to me as well. However, the best solution is something
which
> Luca suggested a few months ago, which is to use the functions defined in
> altivec.h. These are C functions which map directly to Altivec machine
> instructions. I am willing to help out, but I don't find the current
lpc_asm.s
> very easy to follow, and my time is quite limited (my last patch to a free
> software project took almost three months to get into decent shape!).
Is this still my code? IIRC I commented it extensively, but the structure is
certainly non-intuitive.

I'll take a look at it. At the time, I thought I wanted control logic that
was
impossible in C, but that may not be the case. It didn't occur to me that
Linux
and Apple would use different assemblers; elsewhere Apple uses the GNU tools.
I'm also a bit surprised that people are using flac on an Altivecful
Linux/PPC
system (but I did attempt for such a system to fall back to the non-altivec C
code). End digression.

Can you point me to a good reference on altivec.h?

--
Brady Patterson (brady@spaceship.com)
RLRR LRLL RLLR LRRL RRLR LLRL

Josh Coalson wrote:
> --- Luca Barbato <lu_zero@gentoo.org> wrote:
> 
>>Josh Coalson wrote:
>>
>>>since I don't know how to resolve this, in current CVS I have
>>>checked in a system where there are src/libFLAC/ppc/as and
>>>src/libFLAC/ppc/gas selected by configure.  I have also checked
>>>in as many patches as I could make sense of (the cpu.c detection
>>>stuff and the configure.in stuff).  can you guys take a look at
>>>current CVS and help me get something that will build both ways?
>>>after that it will be much easier for me to start looking at
>>>correctness.
>>
>>There is a problem: the AC_CHECK_PROGS() just tests existence and
I'm
>>
>>afraid both osx and linux/ppc have both as and gas executables.
>>running the configure as is will always turn on the "as" path.
>>--with-gas doesn't work to force it.
>>Probably a version check could help.
> 
> 
> how about this logic:
> 
> if cpu is ppc
>   if as exists
>     if as is apple version
>       use as
>     else if as is gnu version
>       use as to assemble but src/libFLAC/ppc/gas directory
>     else
>       no asm
>   else if gas exists
>     use gas
>   else
>     no asm
> 
Seems working to me
> ?
> 
> could you also send me version strings for your versions of
> as/gas for whatever combination of PPC,OS that you have?
as (gnu as) is provided by binutils.

as --version
GNU assembler 2.15.90.0.3 20040415
Copyright 2002 Free Software Foundation, Inc.
This program is free software; you may redistribute it under the terms of
the GNU General Public License.  This program has absolutely no warranty.
This assembler was configured for a target of `powerpc-unknown-linux-gnu'.

I hope it helps

lu

-- 

Luca Barbato

Gentoo/linux Developer		Gentoo/PPC Operational Manager
http://dev.gentoo.org/~lu_zero

I spent a bit of time trying to make the configure behave.

that's the result, I didn't check if the asm output runs correctly 
(looks forcefully disabled) but at least builds as should.

lu

-- 

Luca Barbato

Gentoo/linux Developer		Gentoo/PPC Operational Manager
http://dev.gentoo.org/~lu_zero

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