toms707, a FORTRAN77 code which evaluates the confluent hypergeometric function for complex arguments of large magnitude, by Warren Perger, Atul Bhalla, and Mark Nardin.
toms707 is a version of ACM TOMS Algorithm 707.
The text of many ACM TOMS algorithms is available online through ACM: http://www.acm.org/pubs/calgo or NETLIB: http://www.netlib.org/toms/index.html.
toms707 is available in a FORTRAN77 version.