"Nobody teaches assembly language"

From: Tony Duell <ard_at_p850ug1.demon.co.uk>
Date: Wed Jun 23 22:40:48 2004

>
> > And presumably stage 3 is to grab a VAX11/7xx printset,
> > figure out the microinstruction word, then disassemble the
> > appropriate bit of the microocde and understand how it works.
>
> If you have access to the appropriate printset, that
> might be an option. I don't have it on paper - I know
> that some of the 780 stuff is up at bitsavers, but I
> don't know whether any of the available prints have
> microcode listings.

AFAIK they don't contain microcode listings (some of the PDP11 ones do,
but those machines don't have the POLY instruction).

What I was suggesting (semi-seriously, I did this sort of thing for fun
when I was an undergrad) was taking the printset and working out what the
microcode word bits actually did. Then possibly writing a
cross-disassembler for said microcode. THen taking the microcode binaries
(IIRC the 11/7xx loads its microcode from TU58 or RX01 when it boots.
Then commenting the appropriate bits for the POLY routine.

-tony
Received on Wed Jun 23 2004 - 22:40:48 BST