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 Post subject: Re: CP/M 68k
PostPosted: Sat Oct 28, 2017 10:41 am 
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Joined: Fri Sep 25, 2015 7:57 am
Posts: 9
Hello thanks.

Greeting.


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 Post subject: Re: CP/M 68k
PostPosted: Sat Oct 28, 2017 3:01 pm 
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Joined: Fri Dec 23, 2016 5:18 pm
Posts: 65
Location: New Mexico, USA
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:
viewtopic.php?f=10&t=1570#p4834
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.


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 Post subject: Re: CP/M 68k
PostPosted: Sun Oct 29, 2017 1:22 am 
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Joined: Sat Apr 19, 2014 9:13 pm
Posts: 3
This loop is problematic:

Code:
         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.

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David Schultz


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 Post subject: Re: CP/M 68k
PostPosted: Sun Oct 29, 2017 3:48 am 
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Joined: Fri Dec 23, 2016 5:18 pm
Posts: 65
Location: New Mexico, USA
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.


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TinyBIOS_r4.zip [5.52 KiB]
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 Post subject: Re: CP/M 68k
PostPosted: Sun Nov 19, 2017 3:33 pm 
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Joined: Thu Feb 23, 2017 4:24 am
Posts: 3
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/.
8)


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 Post subject: Re: CP/M 68k
PostPosted: Tue Nov 21, 2017 2:50 pm 
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Joined: Fri Dec 23, 2016 5:18 pm
Posts: 65
Location: New Mexico, USA
Hello,
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.


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 Post subject: Re: CP/M 68k
PostPosted: Thu Nov 23, 2017 6:51 pm 
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Joined: Thu Feb 23, 2017 4:24 am
Posts: 3
Hi,

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.


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