At 05:44 AM 19-05-98 -0700, Daniel A. Seagraves wrote:
Digging thru the VAX 780 manuals...
They have here some crud on how the microcode works. Where it starts and
ends,
field definitions, etc.
I know basically how microcode works. It's the one-cycle instructions like
"gate data bus to address bus" or "gate data bus to ALU".
One MOV can be 2-5 microinstructions.
The large question I have is: How does the MOV translate to microcode?
Does the VAX figure a microcode offset based on the opcode? Is there a table
of entry points somewhere? How is this done?
Another thing, the VAX 780 was microcoded from the console RX01. Does anyone
have a copy of that RX01? Can anyone get a disk image? What else was on
there?
(RT-11? P/OS?)
Well, a large stretch away from my office chair reveals (hidden on the top
shelf under 10 years or so of dust) three manuals:
VAX 11/780 Microprogramming Tools User's Guide AA-H306A-TE
VAX 11/780 Data Path Description AA-H307A-TE
Micro2 User's Guide Reference Manual AA-H531A-TE
These date from the days when some people around here had delusions of
grandeur regarding their ability to write microcode programs. A very quick
look shows that probably all the answers are in the VAX 11/780 Data Path
Description manual. If I didn't have a major planning project to do by
yesterday I might spend some time browsing. Hopefully there'll be someone
else on the list who has access to the manuals or actual practical experience.
Just being annoying...
Never :-)
Huw Davies | e-mail: Huw.Davies(a)latrobe.edu.au
Information Technology Services | Phone: +61 3 9479 1550 Fax: +61 3 9479
1999
La Trobe University | "If God had wanted soccer played in the
Melbourne Australia 3083 | air, the sky would be painted green"