On Tue, Apr 14, 2009 at 11:42:47PM +0200, Anders Carlsson wrote:
> Last Friday I assembled a cassette to IEC port adaptor for the CBM 610,
> a project Ullrich uploaded to Funet/Zimmers FTP back in 1998. It comes
> with a custom Kernel and source code.

The serial bus routines were actually stolen from the Protext cartridge sold
by Voelkner. I had disassembled the routines and made them part of my custom
kernal, because I didn't own one of the parallel floppy disk drives at that
time.

> Now when you mention this club magazine has an article how to replace
> the kernel routines, I suppose it may come handy.

The german word in the article is "Ersatzkernalroutinen". It means that
programs in other banks than bank 15 (where the kernal is located) have
replacement routines that do a bank switch to bank 15 saving all registers and
flags, call a kernal subroutine there and return the results.

Replacing kernal routines is rather easy, since the complete kernal sources
(both, original and the one including the new IEC routines) are available from
my web page. Just grab a copy of ca65 and assemble them to your liking.

> Before looking at the
> article in question, would it allow soft override so one could load the
> new kernel routines from e.g. IEEE floppy or a cartridge and at some
> point swap back to the original kernel?

The serial routines will replace a few vectors. If you make sure that the
vectors are in place after a warm start, it should work. As said above, the
original code was stolen from a cartridge, so there shouldn't be a problem
placing it into a cartridge again.

> Besides my knowledge of German is non-existing but I'd rely on automatic
> translation services to get a rough understanding of the articles. One
> may get some funny results but most of the time it'll probably be fine.

This won't work for two reasons: I've scanned the copies I have (some were
really bad quality) and embedded them into the PDF as graphics. So you have to
OCR them before running the translator. And second, at least part of the
articles are written in a funny way. For example, the header
"Sammelbestellungsbeteiligungsbegehren" means "request for participation in
centralized buying". I'm pretty sure you won't find an automatic translator
that knows words like this:-)

Regards


        Uz


-- 
Ullrich von Bassewitz                                  uz@musoftware.de

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