Antwort: Re: regarding soft floating point support

deepa.vijayaraghavan at deepa.vijayaraghavan at
Wed Oct 6 14:26:45 CEST 2004

   Since I did not have the libgcc_sf.a in the ELDK kit(3.0) that I have, 
I downloaded it from Luckily the 
platform was the same(ppc_4xx).
And, I am able to do floating point now.
Incase, this had not been the case, how do I build libgcc_sf.a? Are the 
sources part of ELDK?

Thanks very much for all your help.



wg at
04.10.2004 22:06

        An:     deepa.vijayaraghavan at
        Thema:  Re: regarding soft floating point support

deepa.vijayaraghavan at schrieb am Fri, 01 Oct 2004 13:25:17 
> Hello Mr.Grandegger,
>          I use IBM PPC 440 based ebony board with RTAI patched 
> linux-ppc-devel OS as target. I also have the ELDK installed in the 
> server. My application needs floating point to work. Could you please 
> me how to enable this? 
>         In the example fp_ppc_8xx, I changed the $TARGET_LIB in the 
> makefile, to $MY_PATH/eldk/ppc_4xx/usr/lib. But only the check 
> gets built. I know that I am missing something(may be many things:))..

There is also a "ifdef CONFIG_8xx" in the Makefile. Just comment
this line and the correspondig one with "endif".

>        If you could give me a rough picture of how soft floating point 
> works, and how to get this enabled for (I think I need to make a build 
> again?), it would be great!

You need to statically link against the libm (for functions like sin, cos,
etc.) the provided soft floating point library emulating the generic
floating point functions, which are executed by a FPU, if avaiable.

> I would like to take this opportunity to also thank you for all the help 

> you've provided through the RTAI mailing list already!

Thanks, you are welcome. But I  prefer that you ask your questions
on the RTAI mailing list as RTAI is a community project.


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