Re: highest bit, statically determined

[Georg Bauhaus <rm-host.bauhaus@maps.arcor.de>]

<kalvink65@gmail.com> wrote:
> How about binary search algorithm with constant execution time:
> 
> Binary_Search_Highest_Bit_In_Octet_2012 : constant :=
>       (if N > (2**4)-1 then -- determine upper or lower nibble
>           -- upper nibble
>           if N > (2**6)-1
>             -- bits 7 and 6
>             if N > (2**7)-1 then
>                 

Isn't this about the same as the recursive one?
(It uses Boolean'Pos around the third if.)

Also, I don't think its complexity is constant, since the number
of conditionals depends on the position of the first 1 bit.
That dependence is gone with the table.

Relative performance might depend on whether shift
and jump is more expensive than another branch of
conditionals. I'm guessing.