🚀 go-pugleaf

In article <240@ssp1.idca.tds.philips.nl> dolf@idca.tds.PHILIPS.nl (Dolf Grunbauer) writes:
>Just a short I-just-want-to-know question: is it true that the DEC-10 systems
>processors were designed for an efficient Lisp implementation, and was it 
>efficient ? (I once heard someone state that these processors were made with
>two high-level languages as aims, one of which was Lisp, and the other I forgot
>(I guess it must be FORTRAN isn't it ?)).

I don't know if Lisp support was a design goal of the PDP-10 architecture,
but I do know that ITS (the Incompatible Timesharing System) included
custom microcode for the KL- and KS-10 processors (I believe the main
effort in porting ITS to a new processor was the microcode).  It added
several instructions, including a few needed by MACLISP.  I don't recall
exactly; it's been a while since I read the microcode, but I think the
new instructions included something special for Deutsch-Schorr-Waite
garbage collection (probably something like atomic test-and-mark with
conditional branch), and perhaps also something for tagged arithmetic.
I may be totally off the mark here, but this is what I seem to recall.
-- 
Mike Haertel <mike@stolaf.edu>
``There's nothing remarkable about it.  All one has to do is hit the right
  keys at the right time and the instrument plays itself.'' -- J. S. Bach