You might look up Nick Tredennick's book "Microprocessor Logic Design: The Flowchart Method" which is sold at Amazon for an obscene price - but maybe some university library has a copy. It's focus is on a methodology for designing microcode, and it uses the design of the single chip 370 to explain it. I suppose it was a PhD thesis.

The main point is that the 370 is NOT an 68000 with a different microcode; instead it is said that it implements the bus interface of the 68K in order to interface easily with existing peripherals (rather than reinventing the wheel). The internal data paths and register sets may be similar between the 68K and the 370 (actually it is quite possible that at Motorola they were aware of IBM mainframe architectures...) but that's all likely. The control unit design described in the book was completely redesigned for the purpose of describing the proposed methodology.

Holger

Am 12.03.2018 um 12:13 schrieb Dave Wade via cctalk:
I don't suppose any one left in IBM has any knowledge of this. Perhaps no
one ever did and it was all done by Motorola. Wikipedia says there were/are
2x68000 CPU's..
.. I would ask on IBM Main...

http://www.cpushack.com/2013/03/22/cpu-of-the-day-ibm-micro-370/

seems to have some names..

Dave



-----Original Message-----
From: cctalk <cctalk-boun...@classiccmp.org> On Behalf Of Lars Brinkhoff
via cctalk
Sent: 12 March 2018 07:02
To: cctalk@classiccmp.org
Subject: XT/370 microcode

Does someone have good connections with people inside IBM?  I'd like to
ask
about 68000 microcode for the XT/370 product.

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