uint8  control 0x7f -> get true  | boundary 0xff -> get FALSE
uint16 control 0x7fff -> get true  | boundary 0xffff -> get FALSE
uint32 control 0x7fffffff -> get true  | boundary 0xffffffff -> get FALSE
uint64 control 0x7fffffffffffffff -> get true  | boundary 0xffffffffffffffff -> get FALSE
[*] boundary values with the top bit set cannot be read back
    with the matching get_uintN: roundtrip broken.