oldtoddler, You should mask variable A for $1111 as adding it to B would be incorrect as far as binary. You should use something like A=A & %00001111 or A=A MIN 15. These statements will limit variable A to a maximum value of 15 or binary %00001111. You could just add the mask as such:
BUSD = (B << 4) + (A & 15)

Dave Purola,
N8NTA