MPC74xx AN2115: Altivec Improvement for FFT

[TonyC]

I am intested in getting an estimated improvement ratio for implementing an FFT in Altivec vs not doing so.  I looked in AN2115 and saw for a size N FFT Altivec is 6.99 times faster than its scalar equivalent.  Is this true?  That seems a bit much.  Does anyone know how long it would take to perform a complex 2D FFT in Altivec for a 64x64 array?

Thanks

(Alban updated title & moved to better board)

Message Edited by Alban on 2006-09-20 08:31 AM

[J2MEJediMaster]

The boost in faster execution of the FFT is reasonable, considering that the Altivec instructions process a bunch of multiply-accumulate operations in hardware. I don't have any Altivec numbers handy. You can probably do a Google search on Altivec and timing and benchmarks and see what falls out.

---Tom