The Lisp Machine

David Gadbois
Sat, 4 Apr 1998 15:08:59 -0600

   Date: Fri, 3 Apr 1998 19:27:53 -0500
   From: "P. T. Withington" <>

   I've put two old (unpublished, until now) papers, "The Lisp
   Machine:  Noble Experiment or Fabulous Failure?", and "The
   Symbolics Virtual Lisp Machine (extended abstract)", which might be
   amusing to this group, at <>.

Wow, great papers!  Any chance of ever seeing the full VLM paper?

It occurs to me that there may be a couple of alternatives to doing
the emulator in assembly.  (This may have relevance if the MIT lispm
sources ever get released.)  Clearly, if performance permits, it would
be better to do an emulator in a high-level language so as to allow
portability and to take advantage of new implementations that have
difference optimization characteristics:  larger, differently mapped
caches, more functional units, register renaming, etc.

1. Reschedule the output of the compiler to better take advantage of
the chip's instruction issue regime, and move stuff around (using
knowledge of the code) to get better instruction cache behavior.

2. Fix the compiler to do the right thing.

Were these (and perhaps other) approaches rejected because doing it by
hand made a big enough difference, or was it a time-to-market thing?

--David Gadbois