Re: How can I link the kernel with libgcc ?

[Carlos Munoz]

Carlos Munoz wrote:

> Lee Revell wrote:
>
> > On Thu, 2006-03-09 at 20:45 -0500, Valdis.Kletnieks@xxxxxx wrote:
> >  
> >
> > > On Thu, 09 Mar 2006 17:44:16 PST, Carlos Munoz said:
> > >   
> > >
> > > > I'm writing an audio driver and the hardware requires floating 
> > > > point arithmetic.  When I build the kernel I get the following 
> > > > errors at link time:
> > > >     
> > >
> > > Tough break, that.  You sure you can't figure a way to either push the
> > > floating point out to userspace
> > >   
> >
> >
> > Audio drivers should never have to directly manipulate the samples -
> > they just manage the DMA buffers and interrupts and wake up the process
> > at the right time.  Mixing, routing, volume control, DSP go in
> > userspace.
> >
> > Lee
> >
> >  
> Hi Lee,
>
> Unfortunately, the driver needs to populate several coefficient tables 
> for the hardware to perform silence suppression and other advance 
> features. The values for these tables are calculated using log10 
> operations. I don't  see a clean way to push these operations to user 
> space without the need for custom applications that build the tables 
> and pass them to the driver.
>
> Thanks,
>
>
> Carlos Munoz
Anyway,

I figured out how to get the driver to use floating point operations. I 
included source code (from an open source math library) for the log10 
function in the driver. Then I added the following lines to the file 
arch/sh/kernel/sh_ksyms.c:

DECLARE_EXPORT(__subdf3);
DECLARE_EXPORT(__muldf3);
DECLARE_EXPORT(__divdf3);
DECLARE_EXPORT(__adddf3);
DECLARE_EXPORT(__floatsidf);
DECLARE_EXPORT(__eqdf2);
DECLARE_EXPORT(__fixdfsi);

Everything works now.

Thanks,


Carlos Munoz
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