FFT C-File

Hello everybody,

im using the Math.h file to do a rfft with 1024 points und q15 datatype.

So far everything works fine, and I get good results. It needs a computation time of ~720us on my CortexM4 @100Mhz.

This is very Impressive, but to long for my application. I only need 80 Values of the Result so my idea was to optimize the function, so that it only calculates useful values.

But there is no source-code behind the math.h functions. Is it possible to get the code? in C? or is it not available.

Otherwise I need to do it from scratch, with means a lot of work for me.

Thanks everybody for reading

Joe