There's a BCPL* compiler bootstrap kit with an INTCODE interpreter in
C.  It compiles on CP/M, MSDOS and Unix.  Executables for CP/M and DOS
are also provided.  You can get it from ftp.syd.dit.csiro.au
[130.155.128.3] in [.languages]bcpl.tar_z (VMS machine).  The kit is
based on the INTCODE bootstrap technique explained in the book BCPL:
The language and its implementation, Richards and another (not certain
of title, book's at home).

Remember, it's an interpretive system for bootstrapping purposes, so
expect a 10 to 20 times hit compared with native code.

The interpreter was done for fun so it's offered as is, no support,
USTL.  But if you do anything weird with it, do let me know.

*BCPL (Basic Combined Programming Language) is a system programming
language invented by Martin Richards. It's a typeless language with
only one data type, the machine word.  Some of its ideas have
influenced C.