Bits of integer

[Joe Horn]

(12-12-2022 10:07 PM)mfleming Wrote:  Why not switch to binary then shift-right until zero?

Here's a brute-force implementation of that method:

LBL A, 0, STO I, Rdn, LBL 0, g ISZ, f SR, g x≠0, GTO 0, RCL I, RTN

GSB A in any binary mode returns the number of bits needed to express X.

It works, but it's horrifically slow:
Input 2^40-1 outputs correct result of 40 in 15 seconds.
Input 2^40 outputs correct result of 41 in 15 seconds.

EDIT: 0 NOT with WSIZE of 64 returns 64 in 22 seconds.