/// <summary>
/// This function is used for floating-point division.
/// </summary>
/// <param name="n2"></param>
//Given two numbers:
// In floating point 1 <= a, b < 2, meaning that both numbers have their top bits set.
// To calculate a / b, maintaining precision, we:
// 1. Double the number of digits available to both numbers.
// 2. set a = a * 2^d (where d is the number of digits)
// 3. calculate the quotient a <- q: 2^(d-1) <= q < 2^(d+1)
// 4. if a >= 2^d, s = 1, else s = 0
// 6. shift a down by s, and undo the precision extension
// 7. return 1 - shift (change necessary to exponent)
public int DivAndShift(BigInt n2)
{
if (n2.IsZero()) return -1;
if (digitArray.Length != n2.digitArray.Length) MakeSafe(ref n2);
int oldLength = digitArray.Length;
//Double the number of digits, and shift a into the higher digits.
Pad();
n2.Extend();
//Do the divide (at double precision, ouch!)
Div(n2);
//Shift down if 'this' >= 2^d
int ret = 1;
if (digitArray[oldLength] != 0)
{
RSH(1);
ret--;
}
SetNumDigits(oldLength);
n2.SetNumDigits(oldLength);
return ret;
}