Jan Burse, created Sep 15. 2018
* We provide a couple of additional bitwise operations. The evaluable
* functions bitcount/1, bitlength/1 and lowestsetbit/1 deal with the
* determination of certain bits of the given integer. The implementation
* is more efficient than would be possible with existing logical,
* shift and test operations.
* bitlength(333) --> 9
* The evaluable functions setbit/2 and clearbit/2 update the given
* integer in a more efficient way than would be possible with existing
* logical and shift operations. The predicate testbit/2 tests a
* particular bit in a given integer, again the implementation is more
* efficient than would be possible with existing logical, shift and
* test operations.
* Warranty & Liability
* To the extent permitted by applicable law and unless explicitly
* otherwise agreed upon, XLOG Technologies GmbH makes no warranties
* regarding the provided information. XLOG Technologies GmbH assumes
* no liability that any problems might be solved with the information
* provided by XLOG Technologies GmbH.
* Rights & License
* All industrial property rights regarding the information - copyright
* and patent rights in particular - are the sole property of XLOG
* Technologies GmbH. If the company was not the originator of some
* excerpts, XLOG Technologies GmbH has at least obtained the right to
* reproduce, change and translate the information.
* Reproduction is restricted to the whole unaltered document. Reproduction
* of the information is only allowed for non-commercial uses. Selling,
* giving away or letting of the execution of the library is prohibited.
* The library can be distributed as part of your applications and libraries
* for execution provided this comment remains unchanged.
* Only to be distributed with programs that add significant and primary
* functionality to the library. Not to be distributed with additional
* software intended to replace any components of the library.
* Jekejeke is a registered trademark of XLOG Technologies GmbH.
* bitcount(X, N):
* Predicate succeeds in N with the number of non-zero bits of X.
* bitlength(X, N):
* Predicate succeeds in N with the highest non-zero bit of X.
bitlength/2, 'SupplementBits', 1).
* lowestsetbit(X, N):
* Predicate succeeds in N with the lowest non-zero bit of X.
lowestsetbit/2, 'SupplementBits', 2).
* setbit(X, Y, Z):
* The predicate succeeds in Z with Y \/ (1 << X).
* clearbit(X, Y, Z):
* The predicate succeeds in Z with Y /\ \ (1 << X).
* testbit(X, Y):
* The predicate succeeds when Y /\ (1 << X) =\= 0.