Thomas R.R. Beetle and pForth: a Forth virtual machine and compiler

R. R. Thomas
St John’s College
Computer Science Tripos Part II 1995
The aim of the project that this dissertation describes was to produce a system suitable for teaching the
language Forth. This would consist of a virtual processor, called Beetle, which would run an ANSI standard
Forth compiler, called pForth (standing for “portable Forth”). The virtual processor would be designed to
match the needs of a Forth compiler, and would be implemented in ANSI C, to make the whole system
easily portable. The compiler would be written in a mixture of virtual processor assembly code and Forth,
and would be provided in compiled form, ready to run on the virtual processor. A simple debugger and user
interface would be provided from which the compiler could be run and monitored. The debugger would
also be used to aid the porting of the Forth compiler to Beetle.
The Forth compiler and virtual processor were based on earlier work by the author, but both were redesigned
and almost completely rewritten, and extended to meet the needs of the project.