ieee-floats
IEEE-Floats provides a way of converting values of type float and double-float to and from their binary format representation as defined by IEEE 754 (which is commonly used by processors and network protocols).

The library defines encoding and decoding functions for the common 32-bit and 64-bit formats, and a macro for defining similar functions for other formats. The default functions do not detect the special cases for NaN or infinity, but functions can be generated which do, in which case the keywords :not-a-number, :positive-infinity, and :negative-infinity are used to represent them.

ASDF-install package (obsolete) http://common-lisp.net/project/ieee-floats/ieee-floats.tgz