Is it possible to roll a significantly faster version of sqrt

Question

In an app I\'m profiling, I found that in some scenarios this function is able to take over 10% of total execution time.

I\'ve seen discussion over the years of fast

Answer 1

Don't know if you fixed this, but I've read about it before, and it seems that the fastest thing to do is replace the sqrt function with an inline assembly version;

you can see a description of a load of alternatives here.

The best is this snippet of magic:

double inline __declspec (naked) __fastcall sqrt(double n)
{
    _asm fld qword ptr [esp+4]
    _asm fsqrt
    _asm ret 8
} 

It's about 4.7x faster than the standard sqrt call with the same precision.