[Tremor] Tremor ARM performance issues

[Nicholas Vinen]

Nicolas Pitre wrote:
>> Nicolas Pitre wrote:
>>     
>>> The section of code where the assembly optimization is doesn't need to 
>>> call any other library functions, does it?  So you may have only the 
>>> mdct code in ARM mode for example.
>>>   
>>>       
>> That's what I would have thought, but it uses a few library routines
>> such as:
>>
>> /usr/libexec/gcc/arm-elf/ld: /usr/lib/gcc/arm-elf/4.1.2/thumb/libgcc.a(_divsi3.o)(__divsi3): warning: interworking not enabled.
>>     
>
> Gah.  That's the division support code.  Well you should really have a 
> toolchain with thumb interworking enabled anyway.  Otherwise the code 
> won't execute at all.
>
>
> Nicolas
>   

Well, as far as I know I do. The problem is that my thumb libraries
don't have "interworking support". That is, they can't be called from
non-thumb code.

This should be fine as long as I am careful to only compile functions in
ARM mode that don't call any library functions. As this only needs to be
functions using the assembly code, it should be possible.

I'd like to recompile my libraries with interworking support too, but I
haven't yet found the option to do so. I've enabled multilib support in
my arm-gcc and will recompile newlib but I'm not sure if that will do
the trick. Hopefully I can make do without it but it would be nice to
have anyway.


Nicholas

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