This is an XPL compiler for the PDP-10 written by Richard L. Brisbey II and R. H. Hey in the mid 70's. This compiler was released into the public domain through DECUS. This source repository includes all the source and text files from the original DECUS release tape plus a port of the compiler that will run on more modern computers. The compiler port requires 64-bit hardware which is used to emulate the 36-bit data word of the PDP-10.