public static void Invert(ulong[] x, ulong[] z)
{
if (Nat192.IsZero64(x))
{
throw new InvalidOperationException();
}
// Itoh-Tsujii inversion
ulong[] t0 = Nat192.Create64();
ulong[] t1 = Nat192.Create64();
Square(x, t0);
Multiply(t0, x, t0);
SquareN(t0, 2, t1);
Multiply(t1, t0, t1);
SquareN(t1, 4, t0);
Multiply(t0, t1, t0);
SquareN(t0, 8, t1);
Multiply(t1, t0, t1);
SquareN(t1, 16, t0);
Multiply(t0, t1, t0);
SquareN(t0, 32, t1);
Multiply(t1, t0, t1);
Square(t1, t1);
Multiply(t1, x, t1);
SquareN(t1, 65, t0);
Multiply(t0, t1, t0);
Square(t0, z);
}
public static void Invert(ulong[] x, ulong[] z)
{
if (Nat192.IsZero64(x))
{
throw new InvalidOperationException();
}
// Itoh-Tsujii inversion with bases { 2, 3 }
ulong[] t0 = Nat192.Create64();
ulong[] t1 = Nat192.Create64();
Square(x, t0);
// 3 | 162
SquareN(t0, 1, t1);
Multiply(t0, t1, t0);
SquareN(t1, 1, t1);
Multiply(t0, t1, t0);
// 3 | 54
SquareN(t0, 3, t1);
Multiply(t0, t1, t0);
SquareN(t1, 3, t1);
Multiply(t0, t1, t0);
// 3 | 18
SquareN(t0, 9, t1);
Multiply(t0, t1, t0);
SquareN(t1, 9, t1);
Multiply(t0, t1, t0);
// 3 | 6
SquareN(t0, 27, t1);
Multiply(t0, t1, t0);
SquareN(t1, 27, t1);
Multiply(t0, t1, t0);
// 2 | 2
SquareN(t0, 81, t1);
Multiply(t0, t1, z);
}
