his program also subtracts the starting range so the actual starting range is always 0; so when a key is solved, it subtracts T-W then adds back original start range. So for 120 bit, it subtracts 800000....effectively reducing search range a full bit to 0 thru 7FFFFF....versus 800000...FFFFFF
Underlined part I found; It's actually
initializing the tames to 0 and the wilds to startingKey and then adds some random number to all of them. The rest of the operations are a mystery I can't find. In particular I can't find the range subtracted/added to a kangaroo, or T-W.
Look at Kangaroo::InitRange() and Kangaroo::InitSearchKey() - range shifting magic is there.