Re: Can optimization-specific codes exist ?

Tom Lane <tgl@netcom.com>
6 Oct 1999 02:10:20 -0400

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Re: Can optimization-specific codes exist ? adrian@dcs.rhbnc.ac.uk (1999-10-04)
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Re: Can optimization-specific codes exist ? tgl@netcom.com (Tom Lane) (1999-10-06)
Re: Can optimization-specific codes exist ? adrian@dcs.rhbnc.ac.uk (1999-10-06)
| List of all articles for this month |
From: Tom Lane <tgl@netcom.com>
Newsgroups: comp.compilers
Date: 6 Oct 1999 02:10:20 -0400
Organization: Netcom Online Communications Services
References: 99-09-118 99-10-011 99-10-016
Keywords: architecture, comment

> : In any event, the only PDP I can think of that was user microprogrammable
> : was the not terribly popular PDP-11/60 and as far as I can tell, the only
> : thing that people did with it was some DSP stuff. -John]


adrian@dcs.rhbnc.ac.uk (A Johnstone) writes:
> A bit off topic, but John is right: only the PDP 11/60 had the
> Writeble Control Store option and not many of those were sold.


Au contraire: the old HYDRA/C.mmp project at CMU made good use of
user-provided microcode in PDP 11/40E processors. 11/60s didn't exist
when we were building C.mmp (*). But AFAIR the microcode was all for
kernel operations (interprocessor semaphores and suchlike) so perhaps
this is too far off topic for comp.compilers.


regards, tom lane


(*) That was the one with 16 processors, 16 memory modules, and
a fat crossbar switch in the middle...
[Could anyone reprogram 11/40s, or did you have to be friends with
Gordon Bell? -John]

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