BeebEm and the Cumana 68008 co-processor

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eelco
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BeebEm and the Cumana 68008 co-processor

Postby eelco » Fri Mar 25, 2016 10:39 pm

Just a quick teaser of the 68k module I've been working on for the BeebEm emulator :)

Cumana68k.png
My Acorn related files are located at:
https://acorn.huininga.nl/

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Pernod
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Re: BeebEm and the Cumana 68008 co-processor

Postby Pernod » Sat Sep 24, 2016 9:28 am

Am surprised no-one else commented on this, well done. Did you ever manage to find the OS9 floppies?
- Nigel

BBC Model B, ATPL Sidewise, Acorn Speech, 2xWatford Floppy Drives, AMX Mouse, Viglen case, etc.

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DutchAcorn
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Re: BeebEm and the Cumana 68008 co-processor

Postby DutchAcorn » Sat Sep 24, 2016 11:56 am

Pernod wrote:Am surprised no-one else commented on this, well done. Did you ever manage to find the OS9 floppies?

IBM Portable PC seems to have them: http://stardot.org.uk/forums/viewtopic.php?f=3&t=6920#p69099
Paul

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eelco
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Re: BeebEm and the Cumana 68008 co-processor

Postby eelco » Thu Oct 20, 2016 9:44 pm

Thank you :) I've been working very irregularly on this project, but I've picked it up again last week. I'll put the code on GitHub soon so anyone can review and make additions. Not really my idea to make yet another fork of BeebEm, but for now it seems like the best option. Sometime in the future it could/should be integrated in a master branch of BeebEm.

@DutchAcorn: Thanks for the heads-up. I'll contact IBM portable PC and see if there's some images available.

By the way, I've been working on support for the PEDL Multiform Z80 co-pro as well :)
pedl1.png

pedl2.png
My Acorn related files are located at:
https://acorn.huininga.nl/

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Pernod
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Re: BeebEm and the Cumana 68008 co-processor

Postby Pernod » Sun Jul 30, 2017 6:25 pm

Did you make any decent progress with either the 68008 or MultiForm? I couldn't find anything of them in your Github.

I'm looking at the MultiForm myself so wondered whether you'd figured out the Z80 side, particularly what's expected at IO addresses &00, &01.
- Nigel

BBC Model B, ATPL Sidewise, Acorn Speech, 2xWatford Floppy Drives, AMX Mouse, Viglen case, etc.

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eelco
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Re: BeebEm and the Cumana 68008 co-processor

Postby eelco » Fri Aug 11, 2017 1:24 pm

AFAIK there are basically just 4 8-bit registers on the PEDL Multiform Z80 co-pro:
2 registers which are host-writable and parasite-readable, and 2 registers which are parasite-writable and host-readable.

A write to &FC00 or &FC01 on the host (6502) can be read from $00 or $01 on the co-processor (Z80).
A write to $00 or $01 on the co-processor (Z80) can be read from &FC01 or &FC02 on the host (6502).

Interestingly though is that the Z80 co-processor firmware also reads/writes to addresses $80 and $81. I have no idea what the difference is between the $00/$01 pair and the $80/$81 pair. The host (6502) code only uses reads/writes to addresses &FC00/&FC01.

Sourcecodes for both the 6502- and the Z80-code can be found here:
https://acorn.huininga.nl/pub/docs/sour ... processor/
My Acorn related files are located at:
https://acorn.huininga.nl/

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Pernod
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Re: BeebEm and the Cumana 68008 co-processor

Postby Pernod » Mon Aug 14, 2017 4:10 pm

eelco wrote:Interestingly though is that the Z80 co-processor firmware also reads/writes to addresses $80 and $81. I have no idea what the difference is between the $00/$01 pair and the $80/$81 pair. The host (6502) code only uses reads/writes to addresses &FC00/&FC01.

Did you ever get the Multiform to actually load anything from floppy?
Mine is currently stuck looking for unmapped IO:

Code: Select all

[:1mhzbus:multiform:maincpu] ':1mhzbus:multiform:maincpu' (F0A3): unmapped io memory read from 8000 & FF
[:1mhzbus:multiform:maincpu] ':1mhzbus:multiform:maincpu' (F083): unmapped io memory write to 0080 = 00 & FF
[:1mhzbus:multiform:maincpu] ':1mhzbus:multiform:maincpu' (F0A3): unmapped io memory read from C300 & FF
- Nigel

BBC Model B, ATPL Sidewise, Acorn Speech, 2xWatford Floppy Drives, AMX Mouse, Viglen case, etc.


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