osiweb.org

Steve Gray wrote: I wish it could do C4P video. Oh well. And speaking of video, it would be nice if our machines could be connected to a modern VGA monitor since monochrome and crt-based monitors are either scare, or expensive and bulky.

There are many small, cheap LCD TVs still out there that have composite video inputs. They make great modern monitors for retro computers.

Steve Gray wrote:It would be nice if we had complete source for the OSI monitor rom (or maybe CEGMON or WEMON) so that it could be re-assembled with a modern assembler.
Steve

I am working on that and would not mind a hand. I have it assembling just fine with Michal Kowalski's 6502 emulator. Just need to the get the video parameters right. Want to help?

Steve Gray wrote: It would be nice if we had complete source for the OSI monitor rom (or maybe CEGMON or WEMON) so that it could be re-assembled with a modern assembler. We could then patch in support for additional features, such as a new disk system using FDC chip (1770, 1793 etc). It would be amazing if we had an SD card storage solution. Things would be so much easier if we could download a game, transfer it to a card, insert into the slot, and boot right into it.
Steve

Source for CEGMON is here. There is a PEEK(65) series which goes through commented disassemblies of at least some of the ROM blocks, but although OCR has been done, these are not really cut-and-paste friendly.

I agree, it would be really nice to have some kind of modern storage option that integrates seamlessly with the OSI hardware and software.

Dave

Anyone using that source (as posted by Dave) for CEGMON should be aware that the usage of some instructions does not work with many assemblers.

That source uses a strict form for such instructions as Rotate Left, Accumulator Shift Left and Local Shift Right when the operations are performed on the accumulator that takes "A' as an argument.
Example: This causes most of the assemblers I tried (such as Kawolski's 6502 emulator) to assign a memory location to the 'A's and your code quickly gets shifted out of sync. In the case of CEGMON, which goes all the way to $FFFF, you are likely to get memory placement or PC roll-over errors. Instead you need to use the less formal form with no argument, such as: Also, be aware that the code is essentially un-commented and none of the versions included will actually work on a stock C1P / SB II.

This is my current SW project. I'll make whatever I end up with available when I get a full hang of the code.

@Dave, do you have a location for the PEEK(65) article you mention?

The code compiles with a65, which compiles on just about any platform. I have been using Ed's version, which is available from his website, Ed's DX-Forth and Utilities Page. I will admit I have never used that form myself, but rather the shorter form with the implied 'A'. Adding in the 'A' doesn't seem to make much sense for the 6502, unlike the 6800 which has both A and B accumulators.

The code is minimally commented. I don't know if it's the original, or a disassembly, but I think it's a disassembly. I believe the C1 version should work, but at the time I created the ZIP, I didn't have a SBII to try it on. I know for certain the C2 version works, because it is running on my C2, which has been modified according to my instructions, which I think are simpler than the officially recommended c2 hack.

The only difference between the C1 and C2 version should be the screen size and the address of the floppy controller. Also, for the C1 there is no need to remap a block of code from $FC00 to $F400 to prevent it from colliding with the floppy controller.

Bill, if you find a problem with the C1 version, and correct it, I would be grateful to have it, and will clean up that distribution. I think it needs better how-to instructions as well.

Dave

If you've not tried Michal Kowalski's 6502 emulator, I highly recommend that you give it a gander.

It not only has an assembler, but it allows you to run the code, inspect memory and registers, set breakpoints and debug parameters, dissemble, save memory in multiple formats, load memory from multiple formats, edit assembler files. etc., etc...

It's also a full windows application. Some might not like that, but I find it handy.

I could go on and on about it. You can find it here:http://exifpro.com/utils.html

@Bill: Nice. I never heard of that one, but I just downloaded it, and it runs just fine under Wine (under OS X). It looks like a really impressive tool, obviously a lot of work went into it. Thanks for the pointer!

Dave

New update in post 1 at top of thread.

@dave. Yes, the 6502 emulator is a real gem!

Definitely interested!

BillO wrote:

Jeff wrote:Interested!

I wonder if this can also be adapted to the C4P. I have one of those with only 8K as well!

/Jeff

If the pin-out of the C4P expansion socket is the same as the C1/SB and it's memory map is open from $2000 to $9FFF, then it should work just fine. Keep in mind, pin-11 of the expansion socket needs to be connected to 5V to supply power to the board.

The memory map is different for the two C4 systems, and they don't have a 40 pin expansion connector, instead they have a 48 pin backplane, with all the signals.

Here is the memory map:

What I am hoping to do is to have one of these for my C1P, and then somehow adapt the design for the 48pin backplane and add a 8K EPROM with BASIC IN ROM to my C4PMF (abandoning the floppy that I cant get going!!), and probably replace the 48K of 2114 RAM with newer chips that are more reliable and use less power and generate less heat. I have some GM76C88-10 chips on hand for that purpose.

Problem is, I am way better at software than I am at hardware. sigh.

/Jeff