I'd interpret that to mean:
Range of values:
0000 0000 0000 0000
to 0000 1111 1111 1111 1111
Given the return type, you'll get:
ARR[0] 0000 0000, ARR[1] 0000 0000
to ARR[0] 0000 1111, ARR[1] 1111, 1111
0 possibly means out of range, 4095 possibly means impact? Suck it and see!