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Which Atari 5200 games means the most to you, and why (these)?


Giles N

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On 10/28/2019 at 5:26 AM, kiwilove said:

The program has to be designed with the 5200 in mind - for a conversion - that will enable a programmer to make both an 8-bit and a 5200 version of the same game.  To date - only one? programmer has supported both platforms - showing that it is possible to do this.

Space Harrier wasn't designed this way - and what it managed to do, was to use all resources possible to enable a decent conversion of Space Harrier possible.

Before this conversion was done - no one would have thought it was possible or a likely candidate for a conversion.

 

A vague comparison would be Dropzone - which works fine on a 48K machine.  That converting this to run on the 5200 was no easy task - yet this was done.  I'm no programmer - so I can't say whether it's possible to convert Space Harrier or not?

 

Harvey

The key to porting any game from the A8 to the 5200 is how much RAM it needs. If a game will run on a 16K A8 then it can almost certainly be ported. If it won't then you need to analyse how much of it is code which can be placed in ROM and how much space it actually needs in RAM. If the resulting RAM requirement does not exceed 16K then it is theoretically possible but it can be very challenging technically. Moving code or variables around is tricky because you have to make sure you have changed all references to them (remember this is using disassembled code, not the original source code). You may also have self-modifying code present which you'll either need to modify or place in RAM. Wrathchild's ports of Dropzone and Mr Do! are truly exceptional.

 

With regards to Space Harrier, my thoughts are that given it runs on the XL/XE which has 62K RAM, not on the 400/800 with 48K RAM, it's unlikely that the RAM requirement would come in under 16K. The Atarimax Ultimate SD cart offers a way of accessing more RAM but it is of very limited use. So until there is a 64K RAM expansion for the 5200 I do not think it would be possible. Note also the A8 hardware registers are nicely located together in a 2K area (hence 62K RAM and not 64K) while on the 5200 they are a little all over the place (I don't know how this would affect any such RAM expansion). Additionally the biggest 5200 cart is currently 512K ROM where Space Harrier uses a 1024K one. I think this would be less of an issue to the hardware designers on AtariAge than the RAM expansion, although the software would have to deal with 16K banks instead of 8K ones.

 

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On 10/31/2019 at 9:53 AM, shanti77 said:

 

Maybe if I had documentation for Atarimax bank switching I could try to do the conversion.

 

If the game will run with 16K RAM then ROM space shouldn't be an issue.

 

You have a couple of choices:

 

(1) There is the bank switching scheme designed by Bryan for M.U.L.E. described here: 

 

 

I can vouch for the 32K bank switching mode which is also supported by the Atarimax Ultimate SD cart. I believe Albert can make these too.

 

Edit: the other advantage of this scheme is that it is supported in Altirra

 

(2) You can use one of the schemes specific to the Atarimax Ultimate SD cart. I described the 8K read/write format here: 

 

 

There is another option where you just have 16K ROM banks which is very similar, you just write to different addresses. I don't remember off-hand, but if it is something you are interested in I can look it up.

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Not really mentioned but two other games that are a must play for me when I fire up my 5200, is the unreleased proto of Blaster and the 8-bit conversion of Satan's Hollow. Blaster plays excellently with a stock 5200 controller. Satan's Hollow works with a standard controller, but plays best with a digital controller through a masterplay clone or redemption adapter.

 

 

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2 hours ago, shanti77 said:

@playsoft I'm interested in 16K mode, it would be good if Altirra supported it.

From the email I have from Steve, you select a 16K read bank by touching $BF80..BFBF. The whole banked area from $4000..$7FFF is then read only memory. However that address range seems like too many 16K banks unless you can map it starting at any 8K offset. I will try it out (I may not have time until after the weekend) and let you know.

 

Edit: I looked through some of my old tests and see that it is $BF80..BF9F to select the appropriate 16K bank.

 

I think with Altirra a game probably needs to appear using the format before it is supported. I used the 8K write/8K read mode in the 5200 version of AtariBlast! but I was also loading from the SD card. I did not even think about asking for this to be supported because of the amount of effort required for just one game.

 

Another possibility would be to use the M.U.L.E. scheme and just put the same code in $8000..$BFFF of every 32K bank. That way when you switch banks only $4000..$7FFF changes. The question is, does Altirra support the M.U.L.E. format in bigger sizes - I will check that too.

 

Edit #2: Altirra supports "*5200 512K cartridge (32K banks)" so assuming you can bank switch as described above this would be a way to run on Altirra. The Ultimate SD cart also supports this format (as well as it's own formats described above). 

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  • 3 weeks later...
On 11/1/2019 at 3:12 PM, Albert said:

Yes.

So special carts could be produced with A400/800/XL games put, or ported, into them, and work fine on a standard 4 or 2 port 5200 console?

 

Could a SD cartridge have more memory, like 64 or 128?

 

Edited by Giles N
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3 minutes ago, Giles N said:

So special carts could be produced with A400/800/XL games put, or ported, into them, and work fine on a standard 4 or 2 port 5200 console?

Yes, but games would need to be modified to work properly with the 5200 to account for the analog controllers, up to four controllers (not that most Atari 8-bit computer games would take advantage of more than two players), and the lack of a computer keyboard (so, no ports of text adventure games). There are probably other differences as well, but those are the most obvious ones.

 

 ..Al

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On 11/18/2019 at 12:19 AM, David Alexander said:

Simultaneous two player action. My Brother and I had many fun hours trying to get through all those mazes.

 

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Wizard of Wor is very cool, a very good ‘early maze/dungeon game’!

 

How many mazes are there?

 

A set number and then you complete the game or endless?

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On 11/1/2019 at 2:27 PM, playsoft said:

So until there is a 64K RAM expansion for the 5200 I do not think it would be possible. Note also the A8 hardware registers are nicely located together in a 2K area (hence 62K RAM and not 64K) while on the 5200 they are a little all over the place (I don't know how this would affect any such RAM expansion). Additionally the biggest 5200 cart is currently 512K ROM where Space Harrier uses a 1024K one. I think this would be less of an issue to the hardware designers on AtariAge than the RAM expansion, although the software would have to deal with 16K banks instead of 8K ones.

 

So, the question would be:

 

Can operational RAM be inserted or ‘given’ to the system via a cartridge (included in the hardware of the cartridge), or would it have to be an external RAM devise inserted via another port?

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On 10/31/2019 at 10:53 AM, shanti77 said:

 

Maybe if I had documentation for Atarimax bank switching I could try to do the conversion.

Ok, so where do we get documentation for Atarimax bank swithing?

 

Perhaps someone could send it to you by PM, if its a tradesecret of sorts?

 

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17 hours ago, Giles N said:

Wizard of Wor is very cool, a very good ‘early maze/dungeon game’!

 

How many mazes are there?

 

A set number and then you complete the game or endless?

I think there are about 8 with specialty dungeons mixed in like the arena and pit. They do repeat after a while but the two player fun cannot be beat.

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On 11/17/2019 at 9:48 PM, Albert said:

Yes, but games would need to be modified to work properly with the 5200 to account for the analog controllers, up to four controllers (not that most Atari 8-bit computer games would take advantage of more than two players), and the lack of a computer keyboard (so, no ports of text adventure games). There are probably other differences as well, but those are the most obvious ones.

 

 ..Al

I was mostly thinking of games like Space Harrier and in general games using a control-stick/pad and a couple of buttons in the gameplay.

 

Could a RAM extension be built into a converter-piece looking device (like such as the one which enables 2600 games to work on the 5200), function as a true RAM together with the other hardware parts of console, with a cartridge slot on top of it?

 

I mean, at least theoretically?

 

Or would a modded 5200

had to be built?

Edited by Giles N
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On 11/20/2019 at 5:35 AM, Giles N said:

So, the question would be:

 

Can operational RAM be inserted or ‘given’ to the system via a cartridge (included in the hardware of the cartridge), or would it have to be an external RAM devise inserted via another port?

I don't think it could be done via the cartridge port. I am not a hardware guy, but my understanding is the issue is that there's no read/write line to the cartridge. The Atarimax Ultimate SD cart gets around this in it's read/write mode by having one address range for writing ($4000..$5FFF) and another address range for reading ($6000..$7FFF). Writing also suffers from indexed addressing being unreliable, I don't know if this is due to lack of a read/write line or is something specific to the Atarimax cart. Either way, I think any such scheme would only be useful for new software specifically written for it, I don't think it would be much help in porting existing A8 games.

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On 11/21/2019 at 11:48 PM, Giles N said:

I was mostly thinking of games like Space Harrier and in general games using a control-stick/pad and a couple of buttons in the gameplay.

 

Could a RAM extension be built into a converter-piece looking device (like such as the one which enables 2600 games to work on the 5200), function as a true RAM together with the other hardware parts of console, with a cartridge slot on top of it?

 

I mean, at least theoretically?

 

Or would a modded 5200

had to be built?

The 2600 Cartridge Adaptor is really a complete 2600 without the RF modulator. The 2-port 5200 (and modded 4-ports) have audio and video inputs on the cartridge pin out that you can feed anything into.

 

It would be completely pointless of course, but you could take an A8, tap off the audio and video signals at the appropriate points and connect them to the correct pins of a 5200 cartridge board. There might be a little more to it than that, but that's effectively how the 2600 adaptor was done.

 

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Didn’t the 5200 have a extra extension port in one of its sides, never used?

 

If all 5200 console-units have these, perhaps one could put a RAM chip into a ... box ... with a connector to the 5200 expansion port?

 

Could that be a possibility for the tech ‘n hardware people?

 

What about taking larger games - from the 400 and 800, break them down into smaller parts, and just include a code of sorts - like in 7800 Fatal Run - to start you on next section.

 

You choose parts from an SD supercart, and start by inserting correct password on later levels (not level 1 of course).

 

 

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You can read about the sort of things which are possible with the expansion port here:

 

 

As for breaking games down in that manner, that's what I did with AtariBlast! for the Ultimate SD cart. However, it is one thing doing that for games that you wrote, because you have the source code and know how they work. Doing that for other games for which only a binary exists would be 100s of hours of work for a programmer. Just to disassemble and fully understand a relatively simple game can take many months. Even then, it may not be possible. If say a game uses a bitmap graphics mode it may need 8K RAM for the screen. If it uses double buffering, so it shows one screen while it constructs the other, then it needs 2 x 8K RAM for the display - and that is all the RAM on the 5200 used up.

 

Even if there was some sort of internal modification available for the 5200, which gave it 48K or more RAM, you would still need programmers to port the games. This would still be a significant undertaking for old games where only the binaries exist. What it might achieve is more new A8 games being made available on the 5200.

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18 hours ago, playsoft said:

You can read about the sort of things which are possible with the expansion port here:

 

 

As for breaking games down in that manner, that's what I did with AtariBlast! for the Ultimate SD cart. However, it is one thing doing that for games that you wrote, because you have the source code and know how they work. Doing that for other games for which only a binary exists would be 100s of hours of work for a programmer. Just to disassemble and fully understand a relatively simple game can take many months. Even then, it may not be possible. If say a game uses a bitmap graphics mode it may need 8K RAM for the screen. If it uses double buffering, so it shows one screen while it constructs the other, then it needs 2 x 8K RAM for the display - and that is all the RAM on the 5200 used up.

 

Even if there was some sort of internal modification available for the 5200, which gave it 48K or more RAM, you would still need programmers to port the games. This would still be a significant undertaking for old games where only the binaries exist. What it might achieve is more new A8 games being made available on the 5200.

I know close to nothing about the details of programming and its interaction with the specifics of hardware!

 

Thanks for good information!

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