Did you guys see this in the datasheet:

Further information about the programming of the EPICS6
DSP core is available in “EPICS6 Programmer’s Guide,
version 1.3, July 3 1997, Author Ron Schiffelers, CIC
development Nijmegen”

Looks like the DSP is a drop in core with it's own documentation. Maybe we can look for the above document.

-Ted