Sunday, 14 February 2010

DOS

OK, I did some DOS based apps in Borland C and some 6502 apps that worked with it on a customer 6502 box that was all originally assembled on a BBC micro.

And now there is a date related bug in it...

And the system is still in use.

17 year old software being resurrected.

Thankfully, over a decade ago, I made a 6502 assembler in C. Getting it to work on a 64 bit version of gcc proved tricky. The code itself had checks for bit packing in structs being as it expected and so even told me it was not going to work. Thankfully gcc has an option -m32 to make as 32 bit target, phew.

And the 6502 app assemblers and works.

Next issue. Borland C on DOS?!?!

OK, I still have my copy of Borland C and the project files.
Wine would not play, but DOSBOX just works.
I am amased.

I am able to run Borland C and compile the app. It runs in a tiny window in the corner of my 30" monitor!

And behold, the app runs, under DOSBOX.

Now for the bug itself. Well, so far I have got as far as understanding some of my 17 year old code and concluding that it could never have worked in the first place?!?! So still digging. I think it will end up being a minor change in a couple of lines of code that handles a BCD packed date in a protocol message over a 9K6 RS485 serial link!

Nostalgia is not what it used to be...

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