public static void Reduce32(uint x, uint[] z)
{
int c = Nat224.SubWord(x, z, 0) + (int)Nat224.AddWord(x, z, 3);
if (c != 0 || (z[6] == P6 && Nat224.Gte(z, P)))
{
Nat224.Sub(z, P, z);
}
}