APU FPU in Virtex ppc405

5 messages, 3 authors, 2008-02-18 · open the first message on its own page

APU FPU in Virtex ppc405

From: A. Nolson <hidden>
Date: 2008-02-08 18:51:46

Hi,

 I have just heard that Xilinx has freed the FPU module for the PPC 
architecture in EDK9.2i. WIll I be able to make it work with my 
Secretlab Linux 2.6.24rc3? Will the eldk toolchain for PPC_4xxfp work? 
Will it be just a matter of integrating it with the XPS BSP?I make an 
extensive use of floating point in my applications and this will be 
really useful.

 Thanks for your help.

Re: APU FPU in Virtex ppc405

From: Grant Likely <hidden>
Date: 2008-02-08 19:32:15

On Feb 8, 2008 11:51 AM, A. Nolson [off-list ref] wrote:
Hi,

 I have just heard that Xilinx has freed the FPU module for the PPC
architecture in EDK9.2i. WIll I be able to make it work with my
Secretlab Linux 2.6.24rc3? Will the eldk toolchain for PPC_4xxfp work?
Will it be just a matter of integrating it with the XPS BSP?I make an
extensive use of floating point in my applications and this will be
really useful.
It's been 2 years since I last played with the FPU core.  At the time
it wasn't a complete FPU so the eldk 4xxfp toolchain would not work.
I had to build my own.  I don't know if the new core is a complete
implementation.

Cheers,
g.


-- 
Grant Likely, B.Sc., P.Eng.
Secret Lab Technologies Ltd.

Re: APU FPU in Virtex ppc405

From: A. Nolson <hidden>
Date: 2008-02-11 11:08:38

I have been checking and it seems that the APU FPU patches will give 
some headaches now, so I will probably wait until they merge them with 
the official GCC release. In any case, it seems that the FPU restricts 
the PowerPC and bus frequencies to a max of 200/100.

Anyway, thanks for the info. I will try to keep track of this in case of 
an update.

Grant Likely wrote:
On Feb 8, 2008 11:51 AM, A. Nolson [off-list ref] wrote:
  
quoted
Hi,

 I have just heard that Xilinx has freed the FPU module for the PPC
architecture in EDK9.2i. WIll I be able to make it work with my
Secretlab Linux 2.6.24rc3? Will the eldk toolchain for PPC_4xxfp work?
Will it be just a matter of integrating it with the XPS BSP?I make an
extensive use of floating point in my applications and this will be
really useful.
    
It's been 2 years since I last played with the FPU core.  At the time
it wasn't a complete FPU so the eldk 4xxfp toolchain would not work.
I had to build my own.  I don't know if the new core is a complete
implementation.

Cheers,
g.


  

Re: APU FPU in Virtex ppc405

From: Thomas Werne <hidden>
Date: 2008-02-17 08:05:09

A. Nolson <alohanono <at> gmail.com> writes:
I have been checking and it seems that the APU FPU patches will give 
some headaches now, so I will probably wait until they merge them with 
the official GCC release. In any case, it seems that the FPU restricts 
the PowerPC and bus frequencies to a max of 200/100.

Anyway, thanks for the info. I will try to keep track of this in case of 
an update.
Hi -

You can get the FPU to work with the 2.6.24rc3 Linux (I got it to work just
yesterday).  There are a couple of small changes you have to make to kernel
config files and to one of the .h files, plus you need to compile with the
-fshort-double flag to convert all doubles into floats.  Let me know if you're
still interested and I can post details and/or patches.

Thomas

--
Thomas Werne
NASA Jet Propulsion Laboratory

All personal and professional opinions presented herein are my
own and do not, in any way, represent the opinion or policy of JPL.

Re: APU FPU in Virtex ppc405

From: A. Nolson <hidden>
Date: 2008-02-18 15:09:37

Hi Thomas,

 I am still very interested in this. It would be really good if you can 
post what you have so far. Did you also have to patch gcc also? Is there 
any penalty in performance when compiling with -fshort-double?

 /Albert

Thomas Werne wrote:
A. Nolson <alohanono <at> gmail.com> writes:

  
quoted
I have been checking and it seems that the APU FPU patches will give 
some headaches now, so I will probably wait until they merge them with 
the official GCC release. In any case, it seems that the FPU restricts 
the PowerPC and bus frequencies to a max of 200/100.

Anyway, thanks for the info. I will try to keep track of this in case of 
an update.

    
Hi -

You can get the FPU to work with the 2.6.24rc3 Linux (I got it to work just
yesterday).  There are a couple of small changes you have to make to kernel
config files and to one of the .h files, plus you need to compile with the
-fshort-double flag to convert all doubles into floats.  Let me know if you're
still interested and I can post details and/or patches.

Thomas

--
Thomas Werne
NASA Jet Propulsion Laboratory

All personal and professional opinions presented herein are my
own and do not, in any way, represent the opinion or policy of JPL.


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