vaxsim2.imp is Peter Robertson and Rob Pooley's Vax code generator for the S-Port intermediate code
of the portable Simula compiler.

See also:
  https://github.com/portablesimula/github.io/tree/master/doc
  https://www.edelweb.eu/Simula/


It is interesting to read in the S-Code documentation

"It is important to realise, that S-code is not seen as a set of instructions which can be executed (or
interpreted) to perform the task specified by the source program. Instead S-code controls a compilation
process, the outcome of which is an executable form of the program. Thus S-code comprises the
instruction set of a compiler, not a (Simula) machine."

which echoes - without acknowlegement - the novel principle of I-Code from Peter Robertson's 1976 PhD Thesis,

"  This  thesis  attempts  to  put  machine-independence and
optimisation on an equal footing, and describes the  use  of
an  intermediate  code  which  takes  a  novel  view  of the
process.   Instead of the intermediate code  describing  the
computation to be performed, it describes the operation of a
code-generator  which  will produce a program to perform the
required computation. "

The design of S-Code is clearly (IMHO) influenced by the design of I-Code...