|Can optimization-specific codes exist ? firstname.lastname@example.org (Chango Cho) (1999-09-28)|
|Re: Can optimization-specific codes exist ? email@example.com (1999-10-03)|
|Re: Can optimization-specific codes exist ? firstname.lastname@example.org (1999-10-04)|
|Re: Can optimization-specific codes exist ? email@example.com (1999-10-04)|
|Re: Can optimization-specific codes exist ? firstname.lastname@example.org (Tom Lane) (1999-10-06)|
|Re: Can optimization-specific codes exist ? email@example.com (1999-10-06)|
|From:||firstname.lastname@example.org (A Johnstone)|
|Date:||6 Oct 1999 09:17:10 -0400|
|Organization:||Royal Holloway, University of London|
|References:||99-09-118 99-10-011 99-10-016 99-10-033|
Tom Lane (email@example.com) wrote:
: Au contraire: the old HYDRA/C.mmp project at CMU made good use of
: user-provided microcode in PDP 11/40E processors.
No, as I said, most PDP-11's were microcoded (not sure about the T-11
chip) but only the 11/60 was marketed with a WCS. There was no user
provided WCS for the 11/40.
"The PDP-11's used on C.mmp were slightly modified to provide software
protection and make the Pc's compatible with a multiprogramming
environment. Also, a writeable microstore was added to the 11/40's."
From: `The C.mmp/Hydra project: an architectural overview' Henry H
Mashburn in `Computer Structures: Principles and Examples' by Daniel P
Siewiorek, C Gordon Bell and Allen Newell
See also, `Computer Engineering: a DEC view of hardware systems
design' by C Gordon Bell, J Craig Mudge and John E McNamara
i.e. John's implication is right, you had to be friends with Gordon
Bell to write your own instructions for an 11/40.
Dr Adrian Johnstone, Senior Lecturer in Computing, Computer Science Dep,
Royal Holloway, University of London, Egham, Surrey, TW20 0EX, England.
Email firstname.lastname@example.org Tel:+44(0)1784 443425 Fax:+44(0)1784 439786
[This has drifted too far away from compilers. -John]
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