APU FPU in Virtex ppc405

Were the issues associated with getting the Xilinx Floating point APU
working with Linux completely resolved ?
Is there a git tree or patch collection with the appropriate patches
etc ?

Dave Lynch 					  	    DLA Systems
Software Development:  				         Embedded Linux
717.627.3770 	       [email protected] 	  http://www.dlasys.net
fax: 1.253.369.9244 			           Cell: 1.717.587.7774
Over 25 years' experience in platforms, languages, and technologies too numerous to list.

"Any intelligent fool can make things bigger and more complex... It takes a touch of genius - and a lot of courage to move in the opposite direction."
Albert Einstein

I had it working at one point ages ago, but that project ended up dropping the work and I haven't touched it since. I think I posted the patches but I don't have a link to them easily at hand.

Cheers,
g.

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

Yes, it's working under Linux. Just do as John, Steve, and Yoshio suggest. That should work then. My problem was that our own cross-tool was not working correctly. But we will fix it in next couple of weeks.

I did very primitive changes and didn't have a patch. In next few weeks we might want to go for powerpc tree then, so I will try to do it all over again.

Shan

My understanding is that with the fpu on the ppc405 (not ppc440), the processor clock rate had to be reduced for the fpu to work. This ended up negating much of the performance benefits of using the fpu.

I don't know the specifics offhand, but Xilinx answer records can be searched. Hopefully I'm wrong, and there can still be a benefit to using the ppc405 fpu.

- John

________________________________________________________________________

John Bonesio
Commercial Linux Solutions
[email protected]
(408) 879-5569

This email and any attachments are intended for the sole use of the named recipient(s) and contain(s) confidential information that may be proprietary, privileged or copyrighted under applicable law. If you are not the intended recipient, do not read, copy, or forward this email message or any attachments. Delete this email message and any attachments immediately.

Shan and I are going to sit down and rebuild our tool chain (a mix of crosstool, linux-from-scratch, and Xilinx patches) next week. Our aim is to quantify the gains/losses of frequency versus hardware acceleration since we have several large scientific apps we plan to run. Like he said, we're hoping to have a handle on the best approach over the next couple of weeks.

Ron