Re: How can I link the kernel with libgcc ?

[Carlos Munoz <carlos@kenati.com>]

Carlos Munoz wrote:

> Lee Revell wrote:
>
>> On Thu, 2006-03-09 at 20:45 -0500, Valdis.Kletnieks@vt.edu 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