bits (8) = xt2(s0) ^ xt3(s1) ^ (s2) ^ (s3); let b2 : bits (8) = x[23..16]; let a3 : bits (8) = x[23..16]; let s3 : bits (8) = (s0) ^ xt2(s1) ^ xt3(s2) ^ (s3); let b2 : bits (8) = (s0) ^ xt2(s1) ^ xt3(s2) ^ (s3); let b2 : bits (8)