This is the Russell Intermediate Code (RIC) generator.  It produces
an intermediate code file (.G) suffix.  This consists of binary encoded
3 address code.  It must subsequently be translated to machine specific
assembly language.  A very rudimentary disassembler (called "display") for
.G files can be obtained by typing make_display in this directory (after
the compiler has been built).  The semantics of the intermediate code
instructions is partially given in "op_codes.h".