Co-processor Menu

[dudleysoft71]

I recently added a PiTubeDirect co-processor to my Model B, I've been working on another project using the co-processor, and while playing with the different processors I keep forgetting which core is which (not difficult with 16 to choose from), so I wrote a little menu to allow me to change between them. I thought other people might find it useful, and the best bit about it is it runs entirely on the host so it can be run from any core that allows the execution of Star commands including DOS, CPM and Panos (and presumable Flex but I haven't been able to test that yet). I put it on an SSD image so on MMFS you can do:

Code: Select all

*DIN COPROMENU
*CPMENU

Or you can Shift-Break boot the disk image, on ADFS if you put the file in $.Library you can call *CPMENU from anywhere, and since it runs on the host it has normal access to the BBC's memory and IO. There seems to be an issue, it's supposed to reset the machine once you select a core, but it's buggy and doesn't always work, you get a blank screen with a flashing cursor, but pressing Ctrl-Break (or just break) will switch you into the new processor core.
This is what the menu looks like:

The processor cores are in order, however I deliberately put Disable at the end so you can simply press UP once and RETURN to disable the processor.
At the moment the menu is very hardcoded, I created the layout using tt-edit, which is copied directly into screen memory, the control codes for the backgrounds are hardcoded into the image, like this:

I just replace the space to the left of the G symbol with CHR$(157) to turn the highlight on.
Here's the first release, if anyone can help with the reboot issue I'm calling

Code: Select all

JMP (&FFFC)

on the host, but it only seems to work with no co-processor active.

*Updated 16/06/2020 - New version with working reset.

copromenu.ssd

(2.25 KiB) Downloaded 89 times

Hopefully some more of you will find this useful.

James Watson

[sydney]

This is a great idea! I will definitely be using this to replace the printed list sellotaped to thetop of my beeb.

[LordVaderUK]

This is excellent, and I too have a ropey bit of paper with all the *FX230,152,... codes. Can you please humour an idiot (me) and post an idiot’s guide to installing and using this? I don’t know for example what a $.Library file is

[dudleysoft71]

This is excellent, and I too have a ropey bit of paper with all the *FX230,152,... codes. Can you please humour an idiot (me) and post an idiot’s guide to installing and using this? I don’t know for example what a $.Library file is

$.Library is a Directory on an ADFS harddisk, if you copy files into it (I use Beeb Image to copy into the directory, you can open both the HDD image and the floppy at the same time making copying simple), any program stored in the directory can be run from anywhere no matter what directory you're currently in (kind of like a simple version of PATH in other operating systems)

Otherwise you can mount the SSD image (using *DIN on MMFS or Turbo MMC) I don't know how you do the same on a Gotek since I don't have one.

I have my own tool to manage my BEEB.MMB file, I wrote it a long time ago when I didn't have access to a windows desktop, it's just a command line tool, but it's useful because I can include it in my build process and it will update the image on my MMB file everytime I build, otherwise you can use MMBImager to add the SSD file to your MMB file, I believe the disk is title COPROMENU so you can use *DIN COPROMENU to insert the correct disk rather than remembering which number it is.

The SSD image is self booting, just shift break and it will load and run the menu.

[dv8]

Here's the first release, if anyone can help with the reboot issue I'm calling JMP (&FFFC) on the host, but it only seems to work with no co-processor active.

You need to reset both the parasite and the host.

The following code will reset the parasite and then do a fake power-on reset of the host:

Code: Select all

SEI
LDA #&A0:STA &FEE0
LDA #&20:STA &FEE0
LDA #&7F:STA &FE4E
JMP (&FFFC)

Or you could just print a message asking the user to press Ctrl+Break.

[dudleysoft71]

Here's the first release, if anyone can help with the reboot issue I'm calling JMP (&FFFC) on the host, but it only seems to work with no co-processor active.

You need to reset both the parasite and the host.

The following code will reset the parasite and then do a fake power-on reset of the host:

Code: Select all

SEI
LDA #&A0:STA &FEE0
LDA #&20:STA &FEE0
LDA #&7F:STA &FE4E
JMP (&FFFC)

Or you could just print a message asking the user to press Ctrl+Break.

Thanks, couldn't find any info about that, looks simple enough. I'll give it a test. I was hoping to avoid having to press break, I'll keep that option as a last resort.

[dudleysoft71]

Okay, I've added the suggested code to the menu, it now resets properly, so it should now be much more suitable for it's original purpose.

Here's the latest download version:

copromenu.ssd

(2.25 KiB) Downloaded 96 times

[mph1708]

When I first saw this program, I thought that that sounds like a great idea.
I too have a problem remembering the codes for each co-processor.

Initially, I was disappointed that I could not get this program to work properly on my BBC Master.
The program runs, and the menu displays etc. - but it wasn't changing to the selected co-processor.

However, I eventually worked out that for the program needs the EXTERNAL TUBE option to be selected on a BBC Master for it to run correctly.
And of course, I intially had my machine set to the INTERNAL TUBE setting.

Mike

[dudleysoft71]

Hadn't even thought about that, I only have a Model B socthat isn't an issue. If I can find out how it differs from the external I can modify it to work with it.

[Mince]

As an aside to this, I submitted a pull request to PiTubeDirect recently to add a program in the 6502 memory space that tells you the *FX command needed and lists all the processor codes. You just type "CALL &2000" to run it, after boot up (or later, although it has to have not been overwritten by something else, but changing to another 6502 processor type will re-install it):

It's not as fancy as a menu and could be expanded to one (although it would need to work on the Electron, too, so no MODE 7) but it gets the processor names from the PiTubeDirect code.

https://github.com/hoglet67/PiTubeDirect/pull/71

[shifters74]

Okay, I've added the suggested code to the menu, it now resets properly, so it should now be much more suitable for it's original purpose.

Here's the latest download version: copromenu.ssd

Hi Dudley,

do you intend to update this for the gecko supported options?

Its a nice user friendly tool to select the processor, thanks for effort to develop it

cheers

shifters

[dudleysoft71]

I was thinking about it, I originally wrote it as a quick hack, it uses a prebuilt screen layout, to make it more useful it'll need a rewrite, the plan is to read a file with the co-processors in so it can be customised based on the ones you want to use. I guess because it does what I need I forget about updating it.

[BigEd]

(In a freshly started 6502 co-pro, the actual list of copros must now be lurking somewhere near &2000.)

[dudleysoft71]

(In a freshly started 6502 co-pro, the actual list of copros must now be lurking somewhere near &2000.)

Which would be useful if it was running on the 6502 co-processor, however the menu runs on the host in 6502 assembly. This was a conscious decision, it allows it to run under any coprocessor that supports executing OSCLI commands, since it doesn't rely on any particular architecture or language being available on the processor, whereas we can always guarantee that the host's capabilities.

[BigEd]

Oh, interesting tactic!

[Mince]

I was thinking, when I added the CALL &2000 code, that there might be some way to trigger a dump of the list data to a specified location — perhaps in the parasite processor and a caller could transfer it across to the I/O processor to use as data using a Tube memory transfer.

It would have to be agnostic of the coprocessor environment and I'm not sure what calls are available to do that: I think there's really only a few OSBYTEs available, so it would all have to go through there, but I haven't thought it out more as I'm not an expert on that.

[mbernardi]

How difficult would it be, to have a toggleable option, to load the appropriate BBC Basic into sideways RAM/ROM prior to selecting the CoPro and resetting?

[jgharston]

You need to reset both the parasite and the host.
The following code will reset the parasite and then do a fake power-on reset of the host:

Code: Select all

SEI
LDA #&A0:STA &FEE0
LDA #&20:STA &FEE0
LDA #&7F:STA &FE4E
JMP (&FFFC)

You need to do more than that as the reset code expects the hardware to have been reset, so you're liable to discover that the firmware finds the hardware is not in the expected reset state, and decides that means the hardware is not present, and disables itself. Plus, the Tube registers aren't at that address on an Electron. You need to do Reset_from_software.