Re: XT/370 microcode
On 2018-03-15 18:35, Robert Armstrong via cctalk wrote: >> You might look up Nick Tredennick's book "Microprocessor Logic Design: >> The Flowchart Method" which is sold at Amazon for an obscene price > > FWIW, there are several copies on Abe Books ranging in price from "only" > $800 (a steal!) to almost $1200. > > I'd love to read it, but that's ludicrous. Is this book bound in solid > gold or something??? It was mentioned few month ago in a newsgroup. So all "reasonable" copies got sold, and the price increased. Just wait ... But it is a nice reading, I don't always agree with N.Tredennick, and explains pretty much, why this CPUs were/are so weird ...
RE: XT/370 microcode
>You might look up Nick Tredennick's book "Microprocessor Logic Design: >The Flowchart Method" which is sold at Amazon for an obscene price FWIW, there are several copies on Abe Books ranging in price from "only" $800 (a steal!) to almost $1200. I'd love to read it, but that's ludicrous. Is this book bound in solid gold or something??? Bob
Re: XT/370 microcode
On 3/15/18, 9:29 AM, "cctech on behalf of Veit, Holger via cctech" wrote: 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 There are two distinct products (well, one product and one project that never made it onto a product) here that get confused. First, the XT/370. This card uses a 68000 with modified firmware (nick was one of the Motorola engineers helping implement this for IBM), as well as a modified 8087, and a stock 68000. Later, Nick left Motorola and came to work at IBM on the Micro/370. The Micro/370 is the 370 on a single chip, and it uses the 68000 bus, but is otherwise different from it. A good writeup of the story can be found here: http://www.cpushack.com/2013/03/22/cpu-of-the-day-ibm-micro-370/ Camiel
Re: XT/370 microcode
On 2018-03-15 09:29, Veit, Holger via cctalk wrote: > 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. He did the 68000 microcode first, and then moved to IBM ...
Re: XT/370 microcode
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 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.
Re: XT/370 microcode
ken said >>> I am not at liberty to post the document. >> >>This? > ... >>Also: > ... >>If so, it might be this: > ... > > There's a difference between "I am not at liberty..." and "what anyone > can google...". The Wayback Machine has it on archive.org https://web.archive.org/web/20150608173633/http://maben.homeip.net/static/S100/IBM/5160%20588%20XT%20370/System%20370%20capability%20in%20a%20desktop%20computer.pdf Whenever I remember, I try and submit pages like this to archive.org's crawler to catalog it for posterity, it only takes a moment. Often they are already there. For instance I recently scanned and submitted an IBM Australia memo my dad had from TJ Watson congratulating IBM employees for their part in Apollo 11's safe return: https://archive.org/details/@galasphere347 Steve
Re: XT/370 microcode
On Tue, Mar 13, 2018 at 6:40 PM, Fred Cisin wrote: > On Tue, 13 Mar 2018, Ken Seefried via cctalk wrote: I am not at liberty to post the document. >>> >>> This? >> >> ... >>> >>> Also: >> >> ... >>> >>> If so, it might be this: >> >> ... >> There's a difference between "I am not at liberty..." and "what anyone >> can google...". > > > There do exist situations where somebody is NOT at liberty to post (NDA, > etc), but the item in question is readily available. The expiration of an > NDA may be long after publication or leakage. > Could always do a LMGTFY.com link, . . . :-) Yeah, Fred...I think that's exactly what I said without being enough of an asshole to suggest LMGTFY.
Re: XT/370 microcode
On Tue, 13 Mar 2018, Ken Seefried via cctalk wrote: I am not at liberty to post the document. This? ... Also: ... If so, it might be this: ... There's a difference between "I am not at liberty..." and "what anyone can google...". There do exist situations where somebody is NOT at liberty to post (NDA, etc), but the item in question is readily available. The expiration of an NDA may be long after publication or leakage. Could always do a LMGTFY.com link, . . . :-)
Re: XT/370 microcode
>> I am not at liberty to post the document. > >This? ... >Also: ... >If so, it might be this: ... There's a difference between "I am not at liberty..." and "what anyone can google...".
RE: XT/370 microcode
-Original Message- From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Paul Berger via cctalk Sent: Monday, March 12, 2018 1:41 PM To: Guy Sotomayor Jr via cctalk Subject: Re: XT/370 microcode The IBM Systems Journal article does not go into great detail but says that a complex of three separate processors are used, a modified 68000 that executes "a large subset of 370 instructions", a standard 68000 to emulate the remainder odf the instructions and a modified 8087 to execute the floating point. I am not at liberty to post the document. Paul. - This one? Seems to be freely available. https://www.researchgate.net/publication/224102395_System370_capability_in_a_desktop_computer - paul
Re: XT/370 microcode
On 12 March 2018 at 18:41, Paul Berger via cctalk wrote: > I am not at liberty to post the document. This? http://ieeexplore.ieee.org/document/5387781/?reload=true Also: https://www.researchgate.net/publication/224102395_System370_capability_in_a_desktop_computer If so, it might be this: https://pdfs.semanticscholar.org/2007/dc1c4e24b021765707191eeef5930b29a69c.pdf -- Liam Proven • Profile: https://about.me/liamproven Email: lpro...@cix.co.uk • Google Mail/Hangouts/Plus: lpro...@gmail.com Twitter/Facebook/Flickr: lproven • Skype/LinkedIn: liamproven UK: +44 7939-087884 • ČR (+ WhatsApp/Telegram/Signal): +420 702 829 053
Re: XT/370 microcode
The IBM Systems Journal article does not go into great detail but says that a complex of three separate processors are used, a modified 68000 that executes "a large subset of 370 instructions", a standard 68000 to emulate the remainder odf the instructions and a modified 8087 to execute the floating point. I am not at liberty to post the document. Paul. On 2018-03-12 2:11 PM, Guy Sotomayor Jr via cctalk wrote: On Mar 12, 2018, at 9:57 AM, Eric Smith via cctalk wrote: On Mon, Mar 12, 2018 at 10:54 AM, emanuel stiebler via cctalk < cctalk@classiccmp.org> wrote: On 2018-03-12 15:49, Eric Smith via cctalk wrote: As the most obvious example of the impedance mismatch between 370 architecture and 68000 microarchitecture, the 68000 is hardwired to have eight each data and address registers, not sixteen GPRs, and microcode can't easily paper over that. I wouldn't bet on that ... I'm fairly sure of it, based on microarchitectural details in the US patents on the 68000 design. I think there was also an article in the IBM Systems Journal when the XT/370 was announced that basically described how this was done and how everything worked. TTFN - Guy
Re: XT/370 microcode
> On Mar 12, 2018, at 9:57 AM, Eric Smith via cctalk > wrote: > > On Mon, Mar 12, 2018 at 10:54 AM, emanuel stiebler via cctalk < > cctalk@classiccmp.org> wrote: > >> On 2018-03-12 15:49, Eric Smith via cctalk wrote: >>> As the most obvious example of the impedance mismatch between 370 >>> architecture and 68000 microarchitecture, the 68000 is hardwired to have >>> eight each data and address registers, not sixteen GPRs, and microcode >>> can't easily paper over that. >> >> I wouldn't bet on that ... >> > > I'm fairly sure of it, based on microarchitectural details in the US > patents on the 68000 design. I think there was also an article in the IBM Systems Journal when the XT/370 was announced that basically described how this was done and how everything worked. TTFN - Guy
Re: XT/370 microcode
On Mon, Mar 12, 2018 at 10:54 AM, emanuel stiebler via cctalk < cctalk@classiccmp.org> wrote: > On 2018-03-12 15:49, Eric Smith via cctalk wrote: > > As the most obvious example of the impedance mismatch between 370 > > architecture and 68000 microarchitecture, the 68000 is hardwired to have > > eight each data and address registers, not sixteen GPRs, and microcode > > can't easily paper over that. > > I wouldn't bet on that ... > I'm fairly sure of it, based on microarchitectural details in the US patents on the 68000 design.
Re: XT/370 microcode
On 2018-03-12 15:49, Eric Smith via cctalk wrote: > As the most obvious example of the impedance mismatch between 370 > architecture and 68000 microarchitecture, the 68000 is hardwired to have > eight each data and address registers, not sixteen GPRs, and microcode > can't easily paper over that. Forgot the smiley: ;-) ;-) ;-)
Re: XT/370 microcode
On 2018-03-12 15:49, Eric Smith via cctalk wrote: > As the most obvious example of the impedance mismatch between 370 > architecture and 68000 microarchitecture, the 68000 is hardwired to have > eight each data and address registers, not sixteen GPRs, and microcode > can't easily paper over that. I wouldn't bet on that ...
RE: XT/370 microcode
Some of the code is now on bitsavers.. Dave From: Eric Smith Sent: 12 March 2018 14:41 To: Dave Wade ; General Discussion: On-Topic and Off-Topic Posts Cc: Lars Brinkhoff Subject: Re: XT/370 microcode On Mon, Mar 12, 2018, 05:13 Dave Wade via cctalk mailto:cctalk@classiccmp.org> > wrote: . Wikipedia says there were/are 2x68000 CPU's.. One Motorola chip was the custom one, the other was normal (as indicated by mask code). There was also an Intel math co, presumably derived from 8087. I used to have an AT/370, which had the same chipset, but I was never able to obtain the software. I very strongly suspect the modified 68000 and 8087 have more than just microcode differences, and that full reverse-engineering of the die would be necessary to accomplish anything useful with the microcode. Neither chip was designed to be a general-purpose microcode engine; both were very heavily tailored for their exact visible architecture, and 370 architecture is enough different that it couldn't be implemented by microcode only changes with no data path changes; the microcode ROMs and PLAs just aren't big enough to work around the data path issues.
Re: XT/370 microcode
As the most obvious example of the impedance mismatch between 370 architecture and 68000 microarchitecture, the 68000 is hardwired to have eight each data and address registers, not sixteen GPRs, and microcode can't easily paper over that. Similarly, the 8087 microarchitecture has hardwired support for binary floating point normalization, and microcode can't efficiently force that to do radix 16 normalization. Both problems could be surmounted (inefficiently) with enough microcode, but the chips were designed with no significant extra microcode ROM and PLA capacity.
Re: XT/370 microcode
On Mon, Mar 12, 2018, 05:13 Dave Wade via cctalk wrote: > . Wikipedia says there were/are > 2x68000 CPU's.. > One Motorola chip was the custom one, the other was normal (as indicated by mask code). There was also an Intel math co, presumably derived from 8087. I used to have an AT/370, which had the same chipset, but I was never able to obtain the software. I very strongly suspect the modified 68000 and 8087 have more than just microcode differences, and that full reverse-engineering of the die would be necessary to accomplish anything useful with the microcode. Neither chip was designed to be a general-purpose microcode engine; both were very heavily tailored for their exact visible architecture, and 370 architecture is enough different that it couldn't be implemented by microcode only changes with no data path changes; the microcode ROMs and PLAs just aren't big enough to work around the data path issues.
Re: XT/370 microcode
Lars Brinkhoff wrote: > Does someone have good connections with people inside IBM? I'd like to > ask about 68000 microcode for the XT/370 product. Martin Ziskind says he has floppy disks with VM/PC, but no way to read them.
RE: XT/370 microcode
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 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.