fp64 is an Xcode 10 Command Line Tool project implementing unlimited length integers (type mb) and multi-precision floating point numbers (type fp). Developer released it as freeware with no license required. fp64 is the successor to fp, which used 32-bit unsigned integers for base 2^32 representation of unlimited length integers. fp64 uses 64-bit unsigned integers for base 2^64 representation of unlimited length integers. The usual set of scientific functions is implemented in type fp, including the hyperbolic functions and the Gamma function. More types and functions will be added in following versions.