CP/M 68k
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Author:  funker [ Sat Oct 28, 2017 10:41 am ]
Post subject:  Re: CP/M 68k

Hello thanks.


Author:  Plasmo [ Sat Oct 28, 2017 3:01 pm ]
Post subject:  Re: CP/M 68k

You are welcome, let me know if you have any questions. The simulator has really helped me porting CP/M68K to two hardware platforms. One hardware was briefly described here:
I need to write up the 2nd 68000 hardware platform, tiny68k. It was one of the Tiny-68xxx series--a low cost 68K in 100mm x 100mm format.

Author:  UhClem [ Sun Oct 29, 2017 1:22 am ]
Post subject:  Re: CP/M 68k

This loop is problematic:

         move.l (a1)+,(a0)+
         dbra d2,RAMdrvW

Because the transfer address (set via setdma) could be odd resulting in an address exception. You must test for addresses that are not word aligned and transfer a byte at a time for that case.

Author:  Plasmo [ Sun Oct 29, 2017 3:48 am ]
Post subject:  Re: CP/M 68k

Thanks to David Schultz on comp.os.cpm for finding a bug in BIOS. The System Guide for CP/M-68K stated that address of DMA buffer can be either odd or even, so move data to/from DMA buffer needs to take that into account. The updated BIOS is attached.

TinyBIOS_r4.zip [5.52 KiB]
Downloaded 650 times

Author:  mr68k [ Sun Nov 19, 2017 3:33 pm ]
Post subject:  Re: CP/M 68k

A "Thank You" shout out to Plasmo for sharing your CP/M 68K work!
Your effort inspired me to put together a simple runtime library
for the 68000 Small C compiler I use, enabling me to compile,
assemble, and unit test a Small C project I'm working on, quite
nicely using Easy68K as the test platform on Windows.
I compiled the Small C compiler to become a cross compiler on
Windows as well. The Small C Compiler would normally run native
on SK*DOS/68K operating system. More info about SK*DOS can be
found at: http://www.users.cloud9.net/~stark/.

Author:  Plasmo [ Tue Nov 21, 2017 2:50 pm ]
Post subject:  Re: CP/M 68k

My Tiny68K is up and running for a few months now. It is a 10MHz 68000 with large DRAM and uses 68681 for I/O but does not have floppy disk controller. It interfaces to CompactFlash instead. Does SK*DOS ports well to a CF-based system? It'll be cool to have Small C running natively.

Author:  mr68k [ Thu Nov 23, 2017 6:51 pm ]
Post subject:  Re: CP/M 68k


I don't have any hands-on experience with Compact Flash, but for what little I know, SK*DOS may have the potential to use CF for mass storage. I would assume using CF in IDE mode. If that's the case, the 8-bit Track/Sector disk addressing can be treated as a 16-bit Logical Sector Number, which works well, as that was what I used for SK*DOS 68K for my SCSI hard disk configuration. The other important consideration is that SK*DOS (6809 and 68K) use a 256 byte block size and a compatible disk format. That will matter if the storage device cannot support 256 byte blocks. If the block size is the common 512 bytes, then some data padding may be needed at the driver level. The SK*DOS web site has a lot of info as far as technical features of the OS, configuration manual, user manual, and source code for the OS, driver samples, utilities, etc. I hope this helps.

Author:  Plasmo [ Tue May 08, 2018 2:59 am ]
Post subject:  Re: CP/M 68k

hancock wrote:
Hi Plasmo and all,

after some I could not prevent myself of digging out my 68k-boards and start over playing around.
Perhaps there should be a new thread on CP/M-68k?

As already stated I was giving up on the rightly reading from floppy-image files because I had not information in which drive they have been created.
I am successfully starting up CP/M in Easy68k, but then it is crashing on read errors in the floppy files.
Is there a solution to it?
Or how did you exactly get to the floppy contents?

Thanks and regards

I'm still new to CP/M68K, but perhaps we can put our heads together and figure out the floppy disk image issues.

Is the floppy image in .imd format? There are not that many CP/M68K systems, is this floppy image of Sage Computers? I think I may know the sector/track format of Sage computer. If you upload the image, I can take a look and see if I can figure out the format.

Author:  hancock [ Thu May 10, 2018 9:53 pm ]
Post subject:  Re: CP/M 68k

That was a quick reply.. :o

Just pulled out my project. I can still boot CP/M and do some commands on the "floppies" (=image-file) like "dir" and "type reloc1.rel"; depending on the file location on the "disk" I am getting errors, though (see screenshot).
I downloaded the file disk images from the internet, it was the best data source that I could find at the time. No information available on the format.
The files are named like "cpm68k_1.1_1of5" and have a size of 251kb;
I will check for more details tomorrow.

For now, I quickly attached a screenshot and the first floppy of my set.


File comment: Screenshot for EasySim with CP/M-68k
Screenshot_CPM68k.JPG [ 65.27 KiB | Viewed 11410 times ]

Author:  Plasmo [ Fri May 11, 2018 6:41 pm ]
Post subject:  Re: CP/M 68k

The "Insufficient memory or bad file header" message indicates either the file is corrupted or the .68k executable is not relocated to the correct TPA location. Have you tried "stat.rel" instead of "stat"?

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