static public void Add(BigNumber src, BigNumber dst, BigNumber result)
{
int j, carry, aexp, bexp, adigits, bdigits;
sbyte sign;
BigNumber A = 0, B = 0;
if (src.signum == 0)
{
BigNumber.Copy(dst, result);
return;
}
if (dst.signum == 0)
{
BigNumber.Copy(src, result);
return;
}
if (src.signum == 1 && dst.signum == -1)
{
dst.signum = 1;
Sub(src, dst, result);
dst.signum = -1;
return;
}
if (src.signum == -1 && dst.signum == 1)
{
src.signum = 1;
Sub(dst, src, result);
src.signum = -1;
return;
}
sign = src.signum;
aexp = src.exponent;
bexp = dst.exponent;
Copy(src, A);
Copy(dst, B);
if (aexp == bexp)
{
// scale (shift) 2 digits
BigNumber.Scale(A, 2);
BigNumber.Scale(B, 2);
}
else
{
// scale to larger exponent
if (aexp > bexp)
{
BigNumber.Scale(A, 2);
BigNumber.Scale(B, (aexp - bexp + 2));
}
else
{
BigNumber.Scale(B, 2);
BigNumber.Scale(A, (bexp - aexp + 2));
}
}
adigits = A.dataLength;
bdigits = B.dataLength;
if (adigits >= bdigits)
{
Copy(A, result);
j = (bdigits + 1) >> 1;
carry = 0;
while (true)
{
j--;
result.mantissa[j] += (byte)(carry + B.mantissa[j]);
if (result.mantissa[j] >= 100)
{
result.mantissa[j] -= 100;
carry = 1;
}
else
{
carry = 0;
}
if (j == 0)
{
break;
}
}
}
else
{
Copy(B, result);
j = (adigits + 1) >> 1;
carry = 0;
while (true)
{
j--;
result.mantissa[j] += (byte)(carry + A.mantissa[j]);
if (result.mantissa[j] >= 100)
{
result.mantissa[j] -= 100;
carry = 1;
}
else
{
carry = 0;
}
if (j == 0)
{
break;
}
}
}
result.signum = sign;
Normalize(result);
}
