private static BigInteger ReduceBarrett(BigInteger x, BigInteger m, BigInteger mr, BigInteger yu)
{
int xLen = x.BitLength, mLen = m.BitLength;
if (xLen < mLen)
return x;
if (xLen - mLen > 1)
{
int k = m.magnitude.Length;
BigInteger q1 = x.DivideWords(k - 1);
BigInteger q2 = q1.Multiply(yu); // TODO Only need partial multiplication here
BigInteger q3 = q2.DivideWords(k + 1);
BigInteger r1 = x.RemainderWords(k + 1);
BigInteger r2 = q3.Multiply(m); // TODO Only need partial multiplication here
BigInteger r3 = r2.RemainderWords(k + 1);
x = r1.Subtract(r3);
if (x.sign < 0)
{
x = x.Add(mr);
}
}
while (x.CompareTo(m) >= 0)
{
x = x.Subtract(m);
}
return x;
}