Is this library correct in terms of Base10 calculations?

[joeventura]

I am exploring to use this library in a financial application where base 10 calculations must be correct within 10 decimal paces.

System.Decimal provides correct base 10 math within its precision range, I believe 28 decimal places.

This library is very exciting because many applications can benefit from a faster, yet correct numeric data type.

How does this library compare to System.Decimal in terms of correctness?

[asik]

The precision of this type is 2^-32, which is approx 2,3283e-10. So it's not quite 10 decimals.
Basic arithmetic (+, -, *, /, %) is all correct within the precision of the type and well-tested.
Other operations have various degrees of accuracy which are usually noted in the description.
Note that the type performs saturation arithmetic which does not preserve mathematical properties once you run into its limits. (All numerical types eventually break down but saturation arithmetic can be tricky to deal with).

That said, I would not recommend using this as a faster replacement of System.Decimal (assuming it's faster...). This type is intended to replace System.Single or System.Double in applications where determinism is important or floating-point hardware is not available.

Note that since it's based on System.Int64, it will perform significantly faster in a 64-bit application where that type fits into registers.