I remember reading, years ago, a paper which provided an algorithm for converting an IEEE 754 into a string using only a fixed number machine word length scalars—but I certainly can't find it now.
http://dl.acm.org/citation.cfm?id=1806623
The title is play on "Printing floating-point numbers quickly and accurately (1996)", which in turn is play on "How to print floating-point numbers accurately (1990)".
http://dl.acm.org/citation.cfm?id=231397 http://dl.acm.org/citation.cfm?id=93559
Rust implementation is heavily commented with beautiful ASCII diagrams.