I was under the erroneous impression that READ_BIT1() would return
0 and 1. It turns out this is not the case -- it simply masks out
the desired bit without shifting to the right. Casting to bool yields
0 and 1 which we then can use to compute the sum.
I didn't have the chance to test this yet, hence the WRITE_BIT line
is commented out still. It's only a matter of getting the inter-
leaving right now, though.
