// Input number; output its residue mod 2
       INP        // read input into acc
       BRZ write  // input = 0 is special case
loop   SUB k2     // keep subtracting 2 from acc
       BRZ write  // if acc = 0, input is even
       BRP loop   // if acc > 0, loop back
                  // (BRP branches if acc >= 0, but we've dealt with acc = 0)
       LDA k1     // if acc < 0, input is odd
write  OUT        // output 0 or 1
       HLT        // halt
k1     DAT 1      // constant 1
k2     DAT 2      // constant 2
// end