On 1/19/15 7:04 AM, "Per =?UTF-8?B?Tm9yZGzDtnci?=
<per.nord...@gmail.com>" wrote:
As a follow-up to
http://forum.dlang.org/thread/fdfwrdtjcawprvvko...@forum.dlang.org#post-qxudiyoygnvvbovhjfgt:40forum.dlang.org
I'm looking for a function that figures out the number of bits that are
needed to represent a zero-based integer:
value-set => bits
=================
0,1 => 1 (*)
0,1,2 => 2
0,1,2,3 => 2 (*)
0,1,2,3,4 => 3
0,1,2,3,4,5 => 3
0,1,2,3,4,5,6 => 3
0,1,2,3,4,5,6,7 => 3 (*)
0,1,2,3,4,5,6,7,8 => 4
....
(*) means full bit usage
http://dlang.org/phobos/core_bitop.html#.bsr
It's actually an intrinsic, reduces to an instruction. Mind the
requirements for 0.
-Steve
