here rows starting from 5 not from 0 or 1.so from 5 to reach 8 we have to cross only 3 rows (5,6,7) with 17 elements in each row.after crossing 51 elements now we are in 8th row .in 8th row we want to go from -8 to 5 only.not cross 5.so 13 elements in 8th row.
so total elements crossed by us are 51+13=64 and each of size 4 so 64*4=256.now add base-address(800) +256 =1056