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hloberg

ExBASIC II by peter kull

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Anyone know anything about this program. seems to be a lot like 'the missing link'. I got a copy (from where??) but it only has a little bit of info on it.

attached is the .dsk in cf7 format readable by TIdir.

XBASIC2.zip

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If I can recall without actually trying your file, there was a group of enhancements for XB that floated about and many of the routines ended up "hard-coded" into the various carts or disk-based flavors of EXB. Like my Triton SXB, for example. They were small assembly routines that you could CALL from your own XB program. I used a CALL CLOCK routine written by Brad Snyder, which he helped me incorporate into my darkoom Timer program. SXB had the routine built-in to the cart, so I added a hook to my Timer program to detect whether EXB of SXB was being used and either load the routine from disk or use it off the cart.

 

The main difference was you'd have to have the disk files present on the system to use them versus installed in the cart. Probably pretty much all the flavors of enhanced XB grew from these routines.

 

Or... didn't TI have a XBII to be released with their TI99/8? Which maybe found life as XBII on the Myarc 9640 Geneve? Don't seem to hear much about the Geneve or the 99/8 for that matter.

Edited by Ed in SoDak

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You can see Exbasic II in action in the TI-99/8 emulation in MESS. However, at this time you cannot use floppy support because we still need a Hexbus floppy emulation. The DSRs on the existing controller cards do not work with Exbasic II. Briefly, Exbasic II sets up the PAB in CPU RAM instead of VDP RAM, and finally locks up; you can start it when you don't plug in any controller for now.

 

On the Geneve we have ABASIC.

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You can see Exbasic II in action in the TI-99/8 emulation in MESS. However, at this time you cannot use floppy support because we still need a Hexbus floppy emulation. The DSRs on the existing controller cards do not work with Exbasic II. Briefly, Exbasic II sets up the PAB in CPU RAM instead of VDP RAM, and finally locks up; you can start it when you don't plug in any controller for now.

 

On the Geneve we have ABASIC.

 

Did the EPROM from the Hexbus controller for the /4A help with that any?

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We already have the Hexbus ROM, but I still need to "guess" a suitable hardware for it; this is the main problem. Apart from the fact that there is still a lot of other things to do before.

 

To do it properly, we need the schematics of a Hexbus floppy. Unlike our 4A peripheral devices, the Hexbus devices are more autonomous; they have an own CPU with a device operating system. On the other hand, as we only have high-level commands on the Hexbus, we can do something like an "abstract floppy drive", that is, when we have a command like "read a sector", we'll deliver the sector contents from the disk image, and not involve a complete disk controller emulation.

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The hardware for the 99/8 Hex-Bus is in the OSO chip, Michael. All of the logic for that is in the complete internal diagram for the chip, which is up on WHT. The rest of the interface uses standard logic chips, all of which are identified on the schematics for the /8. I put all of the development documentation for the 99/8 that survives up on WHT a few years ago. Only one or two documents are missing--and unless someone else has them, they are probably only to be found in TI's archives--if they weren't shredded years ago. I got my set through direct and indirect contacts with three of the engineers that worked on the /8. Between them, they had almost everything that ever existed for it.

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Peter Kull did a lot of programming for the TI in the 1984-1988 timeframe. He did the XB routines here, an XB Compiler, and a FIG Forth cartridge. Most of the programs are a bit hard to find, as they weren't widely distributed in Germany while he was active (and he had them copy protected), and didn't make it out to the rest of the world at all until long after he'd left the TI scene.

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We already have the Hexbus ROM, but I still need to "guess" a suitable hardware for it; this is the main problem. Apart from the fact that there is still a lot of other things to do before.

 

To do it properly, we need the schematics of a Hexbus floppy. Unlike our 4A peripheral devices, the Hexbus devices are more autonomous; they have an own CPU with a device operating system. On the other hand, as we only have high-level commands on the Hexbus, we can do something like an "abstract floppy drive", that is, when we have a command like "read a sector", we'll deliver the sector contents from the disk image, and not involve a complete disk controller emulation.

I do have the Hexbus floppy schematics from Michael Becker. Be glad to send them to you.

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The hardware for the 99/8 Hex-Bus is in the OSO chip, Michael.

 

 

As far as I could figure out from the schematics of the 99/8, and in particular from the OSO chip, the chip is mainly a bus adapter that cannot do much more than converting 8-bit bus words in the console to 4-bit words on the Hexbus and back, and also processing control lines (like "bus available") or raising interrupts. IIRC at the other end of the bus there is a complete controller system together with another 9900 or 9995 that gets the words from the bus and executes some DSR.

 

In MESS I implemented a simple version of the OSO mainly to avoid a lockup.

 

Also, let's see what the schematics reveal. If there is a processor, it will also have some ROM, and this can be difficult to dump; probably only by taking out the ROM and reading it in a special device.

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