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Legacy versus ARM-based 2600 Game Development


Thomas Jentzsch

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4 hours ago, Karl G said:

I think he just means to create a new topic to continue the discussion if desired. 

Yes, that's exactly what I mean, along with moving all the relevant posts from this thread into the new one.  I'm on vacation at the moment so I don't have as much time to do computery things as I normally would, so things are a bit slow for me on that front at this time.  However, I should be able to do so later this afternoon, and I've added it to my task list.

 

Edit: It would be a big help if someone could identify the relevant posts to move from this thread to a new thread.  I just would prefer to keep this discussion relevant to Galagon, and a new thread could be titled something along the lines of, "Legacy versus ARM-based 2600 game development".

 

Thank you,

 

 ..Al

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26 minutes ago, Albert said:

Edit: It would be a big help if someone could identify the relevant posts to move from this thread to a new thread.

 

The ARM discussion starts at post #361 in this topic all the way through. There are a couple of posts that aren't directly about that, but they are spawned by that discussion, so it would be difficult to single them out to keep them here.

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It can be put to another thread. On the other hand - from my side this theme is through and everything is said. What should come more? Some people thinks this way, other people that way about it. Which is okay, not necessary, that all people have the same meaning and that's that. But if other people want to discuss this point deeper, it can be put in an own thread. If not, i would leave it here. Just my opinion.

Edited by AW127
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2 hours ago, Kosmic Stardust said:

Honestly let's all get back to zapping space bugs, and stop worrying so much what the inside of the cart looks like.

Sorry, but IMO this is a valid discussion which must not be chocked off but be put into a separate thread instead.

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  • I like to think of the Atari of our collective imagination.  It is 2020 and they are still making cartridges for the VCS/2600.  Naturally they would use whatever tech was available to make the best games possible.   
  • The only limits would be the acceptable consumer price-point.
  • If new tech allowed better games to flow through the TIA, then so be it. 
  • If new tech allowed better print quality on boxes, manuals, and posters, then so be it.
  • If new tech allowed internet connectivity, iphone control, speech recognition, then let it be. 

It is 2020 and enthusiastic fans are making games for a system they love.  

 

-If you choose to make something in 4k of space, without modern programming tools or hardware, then you will earn all due respect, and it will be understood that you have a fascination with working in that scenario.  If on the other hand you use everything at your disposal, then you will also earn all due respect. 

 

I see no problem with placing a logo on enhanced carts, but that decision, like all others, should be left to the games creator.   

 

 

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12 hours ago, Thomas Jentzsch said:

Sorry, but IMO this is a valid discussion which must not be chocked off but be put into a separate thread instead.

That's what I meant. I can't believe this side discussion reached 100 posts. It was an interesting diversion but definitely belonged in it's own thread.

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37 minutes ago, scrummy said:
  • I like to think of the Atari of our collective imagination.  It is 2020 and they are still making cartridges for the VCS/2600.  Naturally they would use whatever tech was available to make the best games possible.   
  • The only limits would be the acceptable consumer price-point.
  • If new tech allowed better games to flow through the TIA, then so be it. 
  • If new tech allowed better print quality on boxes, manuals, and posters, then so be it.
  • If new tech allowed internet connectivity, iphone control, speech recognition, then let it be. 

It is 2020 and enthusiastic fans are making games for a system they love.  

 

-If you choose to make something in 4k of space, without modern programming tools or hardware, then you will earn all due respect, and it will be understood that you have a fascination with working in that scenario.  If on the other hand you use everything at your disposal, then you will also earn all due respect. 

 

I see no problem with placing a logo on enhanced carts, but that decision, like all others, should be left to the games creator.   

 

 

Honestly it's not as is all these 4k games were developed back in the old school tradition either, using ticker tape and eprom burners. Many pure asm games with no additional hardware were developed on pcs with gigabytes of ram, with the aid of modern software emulators and utilizing various illegal opcodes which offer savings in screen time and coding efficiency. Every byte saved of rom space helps.

 

So while say for instance Pacman 4k would have been possible in theory using existing tech, in principal noone at Atari would have had the capabilities and 30+ years of knowlege and develoment to create a game with that level of polish given the time constraints and corporate culture of the time. I would love to rent a delorian and just slap one of albert's AA store Pacman4k carts on a vintage prototype cartridge, put it on Nolan Bushnel's desk and walk out.

 

Then I come back to the present and find my beloved Nintendo Switch and Mario/Zelda games replaced with Modern Atari Switch, games like Centipede Galaxy Aussault and Missile Command Appocalypse. Nintendo sold off their hardware division to Atari in 1994 after the Jaguar beat out the SNES, and Sega shared a similar fate in 2001...

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If some sort of UltraMusical type cartridge was available in the 80s that would shut George Plympton* up, I would have thought it was awesome!  The only reason 70Mhz coprocessors weren't shoved in carts then is they weren't available then.  The creators of RamPlus, SARA, the original DPC, and the other things that were put in carts then weren't worried about "doping" console for some sort of Olympic sport that doesn't exist.  They were trying to make possible things that otherwise weren't possible and maybe sell a few games in the process.  Hardware hacking is just as valid a part of the hobby as what those "real vanilla 2600 coders" are doing.  I sympathise with the developers who are feeling demotivated by this. 

 

Nobody but the programmers and True Fans understands the fine details?!?!  Since when has this not not been true of any hobby?

 

* PS:  I think Champ Games Galagon is much more like REAL Galaga? Don't you?

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Like I said earlier, I support devs doing what makes them happy, and pulling off technical feats in their playground of choice.

 

I do personally feel some cognitive dissonance in the power of the in-cart hardware vs the console CPU, and an increasing amount of code running in modern hardware. An ARM CPU that's much less capable than the melody one is capable of driving it's own composite video display, with game code and advanced 2D and 3D displays. Andrew suggested it could be possible to have a cloud-connected AI running behind his 2600 chess game. I expect things will only become more skewed as technology advances, and we keep the old gal updated.

 

It's a brave new retro world, I guess. :D

 

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1 hour ago, scrummy said:

I see no problem with placing a logo on enhanced carts, but that decision, like all others, should be left to the games creator.  

I'm unlikely to put the logo on the cartridge itself, as I prefer a clean look for the cartridge.  To say nothing about the fact that there are already many Melody-based games that do not have the logo.  The manual and/or box sometimes feature the Melody logo, but they don't explain what that is.  As has been mentioned earlier in the thread, store entries contain more information about this.

 

 ..Al

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44 minutes ago, Cafeman said:

What is the distinction of Melody vs ARM games?  Same thing?

In the context of this conversation, yes. We do have another ARM-based board (called the Aria) that uses a less powerful chip that allows more interesting bankswitching techniques (as well as onboard RAM, such as SARA support). And that board also allpws writing to the flash RAM space. Star Castle Arcade uses this feature to store high scores and the current color palette selection.
 

My ultimate plan is to use a board like this for all games that don't require DPC+ or CDF support. 
 

  ..Al

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On 1/5/2020 at 10:06 PM, AW127 said:

 

True. And in my mind really begins a little fear, that "normal" Atari-2600 games, could have a hard time in the future. Don't understand me wrong people, i really appreciate quality games like this here (waiting by myself for the digital download of "Galagon" with big anticipation), but on the other hand, there is this little fear growing inside me, that normal Atari-2600 games could have problems, getting enough attention in the future, no matter how good they are and no matter how much good program-code a programmer has put inside. They simply can't do what the ARM-supported games can do and alot people EVEN DON'T KNOW that certain games are ARM-supported. Maybe this should be made more clearly recognizable on the boxes of these games, or something like that? (just a suggestion) And so, the normal technical limits of the Atari-2600 could maybe disappear, but exactly these limits, defines a retro-system.

 

I really hope, that i see things somewhat to negativ here and that also normal Atari-2600 games will have a chance in the future, to be real highlights. Sorry for these thoughts, don't want to dampen the fun about this great game, but the fear in this mentioned point, is there in my mind. And it get's bigger, i can't deny it. Even when i am also looking forward, to get this game here.

There are a lot of 2600 games that have been a lot of fun for a long time and will continue to be fun for the foreseeable future.

 

I don't see why one good looking game that uses newer technology somehow throws cold water on other games that don't use the technology.  

 

Games require a lot more than technology.  There are many, many games on many different systems which are incredibly impressive technically while being complete trash as games.

Just recently I was playing the Rally-X 4k conversion and I was greatly impressed and thought it played well.  I have also dumped quite a few hours into Amoeba Jump, another 4k game.

There are certain games which are just going to need more technology than what the 2600 has to offer to get a good port.  From what I can see, all these impressive tech games are arcade ports.  Even the earliest arcade games just have better hardware than the 2600.

I personally want to enjoy both.  It's cool seeing such impressive games like Zoo Keeper (from what I have seen) and also games like Amoeba Jump and Rally-X.  If the game is good and fun to play, that is what counts.

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On 1/7/2020 at 4:51 PM, RevEng said:

An $18 million dollar Cray supercomputer from 1984 can compute 0.8 Gigaflops. The ARM CPU in the harmony/melody does 0.84 Gigaflops.

 

This is so asymmetric that the 6502+ARM pairing can't reasonably be compared to regular hardware assist found on other platforms.

 

[edit - corrected calculation]

To what extent is this actually being utilized?  IOW, for whatever it is being used for, could not a much slower and less capable chip, but which was optimized to do the particular things it is doing, actually do the work.   That this ARM chip is likely complete overkill and chosen for reasons other than its prowess like price and availability.

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On 1/17/2020 at 9:50 AM, christo930 said:

To what extent is this actually being utilized?  IOW, for whatever it is being used for, could not a much slower and less capable chip, but which was optimized to do the particular things it is doing, actually do the work.   That this ARM chip is likely complete overkill and chosen for reasons other than its prowess like price and availability.

My understanding: Originally it was used just to do bankswitching. That is, to take an address off the 6507 buss and decode it according to the bankswitching scheme, and return the correct data for that address. It effectively duplicated discrete hardware (basically resistors/capacitors) or some very basic hardware anyway that did the same thing - routing an address to point to the correct data.

 

However, in more recent games it's been used for "buss stuffing" performing writes to TIA registers much more quickly than the 6507 can. That's where the 6507 on the '2600 is effecively bypassed, and the ARM takes over the address/data buss and "talks" directly to the TIA chip. Instead of being limited by the 6507 ability to write data to the TIA (generally a load/store on 6507 takes 5 cycles of the 76 available on a scanline), now you have the ARM effectively able to throw MANY changes to the TIA on each scanline. So you can do things the 6507 will NEVER be able to do. Suddenly you are not limited by the 6507, but only by the TIA. So you can put many more things on a scanline, and do things that games could previously not do.

Furthermore, since you've bypassed the 6507 for actually drawing the screen, why not bypass it altogether - and use the grunt of the ARM to do all sorts of nifty calculations. Multiplex sprites, perform complex AI... you name it. All at 70MHz-120MHz depending on the ARM chip. You now have effectively unlimited memory - well, heaps more anyway - that can be accessed hundreds of many times more quickly. You can do many hundreds of times more complex calculations in the spare time between keeping the buss address/data lines all functioning normally.

AND, you can write all that in C instead of fiddly assembler code. ORDERS of magnitude easier.


Best to read original sources as to how it works, because my poor and incorrect explanation is muddying the waters.

It's very clever, and an impressive bit of upgrade.

The point is, yes the ARM is complete overkill for pure bankswitching support. But it's not being used for just that in the new games. It's being used to totally change the "contract" between the 6507 and the TIA. I'm not saying good or bad - I'm just saying that it's a total game changer, literally. There's just no comparison in terms of what's possible when looking at 6507/TIA compared to ARM capability.

 

Edited by Andrew Davie
corrections based on later comments in the thread
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15 minutes ago, Andrew Davie said:

My understanding: Originally it was used just to do bankswitching. That is, to take an address off the 6507 buss and decode it according to the bankswitching scheme, and return the correct data for that address. It effectively duplicated discrete hardware (basically resistors/capacitors) or some very basic hardware anyway that did the same thing - routing an address to point to the correct data.

 

However, in more recent games it's been used for "buss stuffing". That's where the 6507 on the '2600 is effecively bypassed, and the ARM takes over the address/data buss and "talks" directly to the TIA chip. Instead of being limited by the 6507 ability to write data to the TIA (generally a load/store on 6507 takes 5 cycles of the 76 available on a scanline), now you have the ARM effectively able to throw MANY changes to the TIA on each scanline. So you can do things the 6507 will NEVER be able to do. Suddenly you are not limited by the 6507, but only by the TIA. So you can put many more things on a scanline, and do things that games could previously not do.

Furthermore, since you've bypassed the 6507 for actually drawing the screen, why not bypass it altogether - and use the grunt of the ARM to do all sorts of nifty calculations. Multiplex sprites, perform complex AI... you name it. All at 70MHz-120MHz depending on the ARM chip. You now have effectively unlimited memory - well, heaps more anyway - that can be accessed hundreds of times more quickly. You can do many hundreds of times more complex calculations in the spare time between keeping the buss address/data lines all functioning normally.

AND, you can write all that in C instead of fiddly assembler code. ORDERS of magnitude easier.

It's very clever, and an impressive bit of upgrade.

The point is, yes the ARM is complete overkill for pure bankswitching support. But it's not being used for just that in the new games. It's being used to totally change the "contract" between the 6507 and the TIA. I'm not saying good or bad - I'm just saying that it's a total game changer, literally. There's just no comparison in terms of what's possible when looking at 6507/TIA compared to ARM capability.

 

Yes, but is not a slower processor capable of doing the same thing? 

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8 minutes ago, christo930 said:

Yes, but is not a slower processor capable of doing the same thing? 

What's your point?  Yes, a slower processor is capable of handling the bankswitching. It's also possible using discrete components - no processor at all. But that's not what we have. We have a powerful processor (because, why not... it's cheap and versatile) handling the memory addressing, and also being used for bus stuffing and external coprocessing. 

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8 minutes ago, Andrew Davie said:

What's your point?  Yes, a slower processor is capable of handling the bankswitching. It's also possible using discrete components - no processor at all. But that's not what we have. We have a powerful processor (because, why not... it's cheap and versatile) handling the memory addressing, and also being used for bus stuffing and external coprocessing. 

My point is that the capabilities of this ARM chip in this application are being overblown. 

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5 hours ago, frogstar_robot said:

If some sort of UltraMusical type cartridge was available in the 80s that would shut George Plympton* up, I would have thought it was awesome!  The only reason 70Mhz coprocessors weren't shoved in carts then is they weren't available then.

 

But this is a completely unrealistic scenario. Cause when such technic would have existed back at the time, they would not have created a console with the technic of the Atari-2600 at the same time. Then the whole console would have been much much stronger back in the time. Therefore unrealistic.

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5 hours ago, christo930 said:

Yes, but is not a slower processor capable of doing the same thing? 

Slower or non-processor gear can do the same thing, but only if the ARM is merely used as a ROM format simulator. That's not what people are talking about here. The ARM driven games aren't just delivering rom contents; the game logic often runs on the ARM, and the ARM speed+ram comes in handy exactly where the traditional 6502+TIA combo struggles the most - during the display kernel. Instead of being hamstrung by pedestrian things like skipdraw or the combat missile trick, you bang the registers with updates from the ARM one after another, at only 5 cycles a piece. (or less if you're bus stuffing). There are other clever things to be done when you wield that power, and John and Darrell do them, but not with a lesser processor.

 

Look at it another way. ARM driven homebrew authors have said they find it difficult to get the game logic into a single frame. When you amp up the graphics and sounds in a game, there's a penalty in storage and retrieval time, so that leaves less time for the game logic. Here again is proof that a slower processor isn't capable of doing the same thing. 

 

If you still think the ARM-driven capabilities have been overblown, I'd love to hear precisely what you think has been exaggerated, rather than making a general assertion. I thought the discussion has been pretty hyperbole-free so far, on all sides.

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