Hi Owen, > + // (icmp ne (A& C1) 0)& (icmp ne (A& C2), 0) --> missing comma before first 0. > + // select (or (A == 0) (B == 0)) T, F--> select (and (A != 0) (B != 0)) F, T Here you use a different style ("or" rather than | etc). Ciao, Duncan.