The instructions say you can only use addition, subtraction, and shifting operations. However, the proposed solution starts off by testing x>= y. You should add “relational operators” to the list of tools you can use for this problem.
I mainly take issue because the previous problem (4.5) was very strict about this exact thing. It asserted a set of allowed operations, and commented afterward that it is implicit in the instructions that you could not use comparison tests (which was to be assumed since they were not explicitly listed).
(2018 copy of EPI)