Subject: Re: Xilinx Virtex4 FX PPC

From: Clemens Koller <[email-masked]>
Date: Wed, 22 Aug 2007 00:14:22 +0200

Hi, Robert, Josh

>>> Question 1:
>>> Do I need a special glibc for the Xilinx PPC 405????  
>>> Does a normal PPC glibc have more "advanced" instructions compiled in
>>> that will not work on a Xilinx PPC 405??

Have a look at the eglibc project (embedded glibc) at http://www.eglibc.org
I think they support all kind of soft-fp configurations.
(i.e. The stuff seems to work fine on my MPC8540 e500 core with soft-fp)

>> Make sure you're building glibc with soft-fp, or make sure you have
>> CONFIG_MATH_EMULATION enabled in your kernel.  The PPC 405 doesn't have
>> an FPU.
>>
>> josh
> 
> CONFIG_MATH_EMULATION fixed it!!
> 
> What are the opinions out there? 
> Kernel fp or glibc soft-fp??

AFAICT: soft-fp in (e)glibc. They should be faster / hopefully more
optimized to your specific cpu.

Regards,
-- 
Clemens Koller
_______________________________
R&D Imaging Devices
Anagramm GmbH
Rupert-Mayer-Str. 45/1
81379 Muenchen
Germany

http://www.anagramm-technology.com
Phone: +49-89-741518-50
Fax: +49-89-741518-19