[ros-dev] ping Alex regarding log2() for scheduler

Royce Mitchell III royce3 at ev1.net
Wed Mar 23 16:04:48 CET 2005


Magnus Olsen wrote:

>Hi I have not test run this code. But i think this form maby 
>are faster that v3 of  Royce  Mitchell III code 
>it leave to the compiler to optimze it more or I complete wrong 
>
> int highest_bit ( unsigned int i )
> {
>     int ret = 0;
>     int n ;
>     int t;
>     int x;
>
>    for (t = 0; t>3;t++)
>   {
>      x = (16 << t);
>      n = i >> x;
>     if ( n )  i = n, ret  += x ;
>   }
>      return ret + (i>>1);
>}
>
>  
>
Magnus,

Well... I was skeptical at first....

Your code is indeed faster, but it is not outputting correct results, so 
if you can tweak it to output correct results without sacrificing speed 
I will indeed be impressed!

/me crosses fingers ;)

Royce3



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