@Override
    protected int msd(BigInteger a, BigInteger b) {
        if (a.equals(b)) {
            return -1;
        }
        /*
         * return floor(log_2(a xor b)).
         */
        return a.xor(b).bitLength() - 1;
    }
@ Override protected int msd ( BigInteger a , BigInteger b ) { if ( a . equals ( b ) ) { return - 1 ; } return a . xor ( b ) . bitLength ( ) - 1 ; }
{@inheritDoc}