Fastest Inverse Square Root on iPhone

Question

I\'m working on an iPhone app that involves certain physics calculations that are done thousands of times per second. I am working on optimizing the code to improve the fra

Answer 1

https://code.google.com/p/math-neon/source/browse/trunk/math_sqrtf.c <- there's a neon implementation of invsqrt there, you should be able to copy the assembly bit as-is