/** Do one the the 16 possible bit-wise operations of two IntNums. */
public static IntNum bitOp(int op, IntNum x, IntNum y)
{
switch (op)
{
case 0: return(IntNum.zero());
case 1: return(and(x, y));
case 3: return(x);
case 5: return(y);
case 15: return(IntNum.minusOne());
}
IntNum result = new IntNum();
setBitOp(result, op, x, y);
return(result.canonicalize());
}