PDP11 M9301-Yx ROM dumps

Noel Chiappa jnc at mercury.lcs.mit.edu
Fri May 13 12:12:39 CDT 2016

    > From: Glen Slick

    >> No, but I do have a un-annotated dump in octal. Can you point me at
    >> a description of Intel HEX format

    > Or you could just use the SRecord tool package to convert between
    > binary / Intel hex / Motorala hex

I had a look through the doc, but I couldn't find 'octal' anywhere... :-)

And anyway, my format is not identical to either Intel or Motorola, so I'd
have to write a converter _anyway_, to get from my format to something a tool
would understand. (Converting my dumper to emit Intel instead of my format
would still mean a lot of work, because I have all these boards dumped in my
format - I'd have to swap them all into the machine to get Intel-format dumps.)

Plus to which the M9301 ROM format is kind of wierd; the high addresses on
the bus (173000 and up) go in the low locations in the ROM, and the low
locations (165000 and up) go in the high, _and_ the low bits (0377) of each
word (i.e. the two ROMs which hold the low bits) have to be inverted because
of a kludge on the M9301 having to do with the way it writes the contents of
the switch to the bus when the machine is starting. So all in all, it's just
easier to...

    >> I already have a program to read my octal dump things, so I'll just
    >> have to tweak that a bit.

Which turned out to be pretty easy - probably easier (for me, at least) than
understanding the documentation on the SRecord tool page well enough to
understand how to make it do what was needed... :-)

    > From: Pete Turnbull

    >> Can you point me at a description of Intel HEX format

    > Take a look at http://www.dunnington.info/public/IntelHEX
    > There's a description and also some code you could adapt.

Thanks for that; alas, by the time I saw it, my brain had turned on and I
remembered this wonderful thing called 'Google', which had led me to info
about the format! :-)


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