private static void MultiDivide(BigInteger leftSide, BigInteger rightSide, out BigInteger quotient, out BigInteger remainder)
{
if (rightSide.IsZero)
{
throw new DivideByZeroException();
}
DType val = rightSide.m_digits[rightSide.m_digits.DataUsed - 1];
int d = 0;
for (uint mask = DigitsArray.HiBitSet; mask != 0 && (val & mask) == 0; mask >>= 1)
{
d++;
}
int remainderLen = leftSide.m_digits.DataUsed + 1;
DType[] remainderDat = new DType[remainderLen];
leftSide.m_digits.CopyTo(remainderDat, 0, leftSide.m_digits.DataUsed);
DigitsArray.ShiftLeft(remainderDat, d);
rightSide = rightSide << d;
ulong firstDivisor = rightSide.m_digits[rightSide.m_digits.DataUsed - 1];
ulong secondDivisor = (rightSide.m_digits.DataUsed < 2 ? (DType)0 : rightSide.m_digits[rightSide.m_digits.DataUsed - 2]);
int divisorLen = rightSide.m_digits.DataUsed + 1;
DigitsArray dividendPart = new DigitsArray(divisorLen, divisorLen);
DType[] result = new DType[leftSide.m_digits.Count + 1];
int resultPos = 0;
ulong carryBit = (ulong)0x1 << DigitsArray.DataSizeBits; // 0x100000000
for (int j = remainderLen - rightSide.m_digits.DataUsed, pos = remainderLen - 1; j > 0; j--, pos--)
{
ulong dividend = ((ulong)remainderDat[pos] << DigitsArray.DataSizeBits) + (ulong)remainderDat[pos - 1];
ulong qHat = (dividend / firstDivisor);
ulong rHat = (dividend % firstDivisor);
while (pos >= 2)
{
if (qHat == carryBit || (qHat * secondDivisor) > ((rHat << DigitsArray.DataSizeBits) + remainderDat[pos - 2]))
{
qHat--;
rHat += firstDivisor;
if (rHat < carryBit)
{
continue;
}
}
break;
}
for (int h = 0; h < divisorLen; h++)
{
dividendPart[divisorLen - h - 1] = remainderDat[pos - h];
}
BigInteger dTemp = new BigInteger(dividendPart);
BigInteger rTemp = rightSide * (long)qHat;
while (rTemp > dTemp)
{
qHat--;
rTemp -= rightSide;
}
rTemp = dTemp - rTemp;
for (int h = 0; h < divisorLen; h++)
{
remainderDat[pos - h] = rTemp.m_digits[rightSide.m_digits.DataUsed - h];
}
result[resultPos++] = (DType)qHat;
}
Array.Reverse(result, 0, resultPos);
quotient = new BigInteger(new DigitsArray(result));
int n = DigitsArray.ShiftRight(remainderDat, d);
DigitsArray rDA = new DigitsArray(n, n);
rDA.CopyFrom(remainderDat, 0, 0, rDA.DataUsed);
remainder = new BigInteger(rDA);
}
