[maemo-developers] Performance of floating point instructions

[From: Alberto Mardegan]

Hi all,
   in maemo-mapper I have a lot of code involved in doing transformations from 
latitude/longitude to Mercator coordinates (used in google maps, for example), 
calculation of distances, etc.

I'm trying to use integer arithmetics as much as possible, but sometimes it's a 
bit impractical, and I wonder if it's really worth the trouble.

Does one have any figure about how the performance of the FPU is, compared to 
integer operations?

A practical question: should I use this way of computing the square root:

http://en.wikipedia.org/wiki/Methods_of_computing_square_roots#Binary_numeral_system_.28base_2.29

(but operating on 32 or even 64 bits), or would I be better using sqrtf() or sqrt()?


Does anyone know any tricks to optimize certain operations on arrays of data?

Ciao,
   Alberto

-- 
http://www.mardy.it <-- geek in un lingua international!