---

6.28 RM 13.7.1(16): Address Operations ¶

"Operations in System and its children should reflect the target environment semantics as closely as is reasonable. For example, on most machines, it makes sense for address arithmetic to ’wrap around’. Operations that do not make sense should raise Program_Error."

Followed. Address arithmetic is modular arithmetic that wraps around. No operation raises Program_Error, since all operations make sense.