Section: Floating point processing Taps (3stap)
Updated: November 2020
function::fp_to_string - Convert 64 bit floating point to string
the 64 bit floating point stored in long
number of digits after decimal point
Given a 64 bit floating point, which is stored in long, use the long value to initiate self-defined float64_t type, then apply the f64_to_i64 function to get the string representation.