Oops, your absolutely right. The DUE has an ARM M3 and not M4 core. Still, its very strange to me why the Arduino 1.5 IDE comes with ARM M4 c and s files.
Anyways, any thoughts about a FFT library which will take advantage of the ARM M3's float operation capabilities (for example...) would be much appreciated.
I did find one which does compile:http://www.librow.com/articles/article-10
It uses "double" for all of its data types. Does the ARM M3 process doubles as efficiently as floats? Or is it emulated and therefore take a much longer time to process?