If you need to use printf, the COPRTHR 2.0 SDK solves this issue with only a few bytes of code (the character string is even stored off-chip). And you can call arbitrary routines on the host from an Epiphany core with little overhead. Many of the details are in "". You can download the COPRTHR SDK here:
http://www.browndeertechnology.com/reso ... prthr2.htm