18 replies to this topic

[jbourke]

Hi all,

I have been working on a TI/99-4A emulator for a while and got the basic console working (sans sound). The next step is loading and using cartridges, I have got several working now. One that doesn't cooperate is TI Extended Basic, every input provides a "* BREAKPOINT" message.

Would there be more in-depth / technical information available about EB? Things like scratchpad usage, flag bits, differences with TI Basic, disassembly of GROM and ROM etc?

Thanks!

John

[Willsy]

Hmmm... strange... if you're emulating the hardware correctly then the software should take care of itself.

I'd suggest areas to focus attention on would be the GROM interface (auto incremental addressing apparently isn't as straightforward as one would think - there's some gotchas) and the XB bank switching method.

Best of luck - look forward to seeing your emulator!

Mark

[kl99]

I suggest investing in the Cyc DVD from Cadd99. It contains over 60.000 pages about the TI-99.
All in PDF form in original look and with full text search. PDF files include fixes and comments.
You get indexes who help you find what you need!
It's only avaiable to PC99 (Light) customers though - as a bundle it's a $72 USD invest.
I highly recommend the Cyc to anyone who wants to do more than gaming with the TI-99!

It appears that Mike Wright and his wife are working every day to expand the Cyc DVD.
It's unbelievable how much work and love goes into this product.

I wish you the best as well for your emulator project.

[jbourke]

Thanks for the helpful replies. I am pretty sure I have got the GROM interface covered as I have been unable to fault TI Basic with whatever I have thrown at it so far. The thing I read about XB bank switching (thanks BTW Thierry for your excellent site) is that apparently the whole 8K is switched instead of the upper 4K.  But as the lower 4K is the same in both banks switching 8 or 4K shouldn't make a difference. Anyway I have tried both methods :-)

It would be great to have a TI intern for XB, got so much info from Heiner Martin's book; fantastic effort.

I will definitely look into the Cyc DVD, great tip.

Cheers,

John

[Tursi]

Check your keyboard/CRU interface... XB handles it differently than TI BASIC does. If you are only seeing issues after entering a command, it's either keyboard interface or bank switching. (Also make sure you have the banks the right way around! )
If you have other GROM carts working, then most likely the GROM part of XB will work for you.

XB ROM bank switching is only the upper 4k, but all the ROMs you find on the net, and most emulation, does switch the full 8k range, with the first 4k just mirrored in the ROM images. Classic99 switches the full 8k even though it's technically incorrect to. Atarisoft carts, and Jon's 379 carts, need the full 8k switched.

As far as I know there's no published disassembly of XB's ROMs, though I think our resident GPL expert (RXB) has released some of the GPL source! Search up some of his RXB update threads.

Cyc is pretty impressive.. I didn't realize it was still being udpated. My own copy is a few years old now.

[Willsy]

Tursi, on Mon Feb 13, 2012 4:57 PM, said:

XB ROM bank switching is only the upper 4k

Whoa! Ambiguity Police! PULL OVER!

Define "upper" - I always find stuff like that confusing! Do you mean the numerically higher 4K?

[Tursi]

Willsy, on Mon Feb 13, 2012 5:36 PM, said:

Whoa! Ambiguity Police! PULL OVER!
Define "upper" - I always find stuff like that confusing! Do you mean the numerically higher 4K?

Sorry, officer. I was just engaging in conversation!

XB contains 12KB of ROM. There is 4k of fixed memory mapped from >6000 through >6FFF. A second 8k of ROM is mapped as two 4k pages at >7000 through >7FFF, 4k at a time. I define smaller numbers as "lower" than larger numbers, thus my informal reference to the memory blocks (being based at >6000 or >7000) as "upper" or "lower".

I'll pay the ticket.

[OLD CS1]

Awww, and I grabbed my camera to catch some police brutality.

[jbourke]

Tursi, on Mon Feb 13, 2012 4:57 PM, said:

Check your keyboard/CRU interface... XB handles it differently than TI BASIC does. If you are only seeing issues after entering a command, it's either keyboard interface or bank switching.

Would you have any more info on the CRU interface differences?

Some commands do work (NEW, NUM, RES, LIST, BYE) and I can type in/list basic programs without any problems. I am comparing the scratchpad with Classic99 and V9T9 but haven't found any substantial differences so far. It would be nice to know where XB keeps the "BREAK" flag as this must be a different location to TI Basic.

Cheers,

John

[RXB]

Tursi, on Mon Feb 13, 2012 4:57 PM, said:

Check your keyboard/CRU interface... XB handles it differently than TI BASIC does. If you are only seeing issues after entering a command, it's either keyboard interface or bank switching. (Also make sure you have the banks the right way around! )
If you have other GROM carts working, then most likely the GROM part of XB will work for you.

XB ROM bank switching is only the upper 4k, but all the ROMs you find on the net, and most emulation, does switch the full 8k range, with the first 4k just mirrored in the ROM images. Classic99 switches the full 8k even though it's technically incorrect to. Atarisoft carts, and Jon's 379 carts, need the full 8k switched.

As far as I know there's no published disassembly of XB's ROMs, though I think our resident GPL expert (RXB) has released some of the GPL source! Search up some of his RXB update threads.

Cyc is pretty impressive.. I didn't realize it was still being udpated. My own copy is a few years old now.

Actually I released the TI XB Assembly ROMs source twice. And mailed copies to many people. I even uploaded a copy to the Don O'Niel site too.
Oddly all of them just vanished. To make matters worse I lost my hard copies in a loan that got burnt up in a house fire.
Then my hard drive crashed and lost the last copy.

[RXB]

jbourke, on Tue Feb 14, 2012 1:40 AM, said:

Tursi, on Mon Feb 13, 2012 4:57 PM, said:

Check your keyboard/CRU interface... XB handles it differently than TI BASIC does. If you are only seeing issues after entering a command, it's either keyboard interface or bank switching.

Would you have any more info on the CRU interface differences?

Some commands do work (NEW, NUM, RES, LIST, BYE) and I can type in/list basic programs without any problems. I am comparing the scratchpad with Classic99 and V9T9 but haven't found any substantial differences so far. It would be nice to know where XB keeps the "BREAK" flag as this must be a different location to TI Basic.

Cheers,

John

Down load my RXB source code in RXB. The source lists all the flags used and all the bits are explained pretty well.

[jbourke]

Thanks RXB, source code is_big_ help. Haven't found the culprit yet but  I am seeing some vague signs pointing towards the CRU.

Cheers,

John

[RXB]

Glad to hear you are making progress.

Rich

[Rod Van Orden]

Rich:
When Extended Basic V2.5 was released, was there some sort of documentation or a manual with it?
Or was it just a bug fix for TI Extended Basic V1.0?

You have very good documentation for RXB, by the way! Outstanding work!


Rod Van Orden
San Diego, California

[RXB]

Tursi, on Mon Feb 13, 2012 4:57 PM, said:

Check your keyboard/CRU interface... XB handles it differently than TI BASIC does. If you are only seeing issues after entering a command, it's either keyboard interface or bank switching. (Also make sure you have the banks the right way around! )
If you have other GROM carts working, then most likely the GROM part of XB will work for you.

XB ROM bank switching is only the upper 4k, but all the ROMs you find on the net, and most emulation, does switch the full 8k range, with the first 4k just mirrored in the ROM images. Classic99 switches the full 8k even though it's technically incorrect to. Atarisoft carts, and Jon's 379 carts, need the full 8k switched.

As far as I know there's no published disassembly of XB's ROMs, though I think our resident GPL expert (RXB) has released some of the GPL source! Search up some of his RXB update threads.

Cyc is pretty impressive.. I didn't realize it was still being udpated. My own copy is a few years old now.

I sent a copy of the XB ROMs source to many people  and uploaded it onto the WHT FTP years ago.

I have no idea what happened to all the copies I sent out. I would have thought at least one would have survived.

Rich

[Gazoo]

Rod Van Orden, on Fri Jan 4, 2013 1:26 PM, said:

Rich:
When Extended Basic V2.5 was released, was there some sort of documentation or a manual with it?
Or was it just a bug fix for TI Extended Basic V1.0?

You have very good documentation for RXB, by the way! Outstanding work!


Rod Van Orden
San Diego, California

Extended Basic v2.5 documentation is here:

ftp://ftp.whtech.com/emulators/pc99/modules/Extended%20Basic%20v2.5/xb25doc.txt

Gazoo

[Vorticon]

kl99, on Mon Feb 13, 2012 6:53 AM, said:

I suggest investing in the Cyc DVD from Cadd99. It contains over 60.000 pages about the TI-99.
All in PDF form in original look and with full text search. PDF files include fixes and comments.
You get indexes who help you find what you need!
It's only avaiable to PC99 (Light) customers though - as a bundle it's a $72 USD invest.
I highly recommend the Cyc to anyone who wants to do more than gaming with the TI-99!

It appears that Mike Wright and his wife are working every day to expand the Cyc DVD.
It's unbelievable how much work and love goes into this product.

I wish you the best as well for your emulator project.

I really wish Mike would un-bundle the Cyc from PC99. The latter is a DOS only product, and in this day and age forcing users to purchase a severely outdated emulator is ridiculous...

[Rod Van Orden]

Gazoo:
Thank you for the info and link on the XB V2.5 documentation. It is exactly what I was looking for......
There is a whole lot of TI stuff out here, and sometimes its hard to find the "tree" you need because
the "forrest" is in the way...... The sad fact is I have been running XB V2.5 for the past 2-3 years without
knowing all the enhancements that Tony Knerr had assembled...... I was using the TI XB manual, and everything
worked very well.....

Thanks again!

Rod Van Orden
San Diego, California

[Gazoo]

Rod Van Orden, on Mon Jan 7, 2013 2:06 PM, said:

Gazoo:
Thank you for the info and link on the XB V2.5 documentation. It is exactly what I was looking for......
There is a whole lot of TI stuff out here, and sometimes its hard to find the "tree" you need because
the "forrest" is in the way...... The sad fact is I have been running XB V2.5 for the past 2-3 years without
knowing all the enhancements that Tony Knerr had assembled...... I was using the TI XB manual, and everything
worked very well.....

Thanks again!

Rod Van Orden
San Diego, California

You're welcome.

I'll be sure to thank Tony for your kind words.

Gazoo