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Does Stella Abide by the Atari 2600 Hardware Limitations?


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#1 OldAtAtari OFFLINE  

OldAtAtari

    Star Raider

  • 98 posts
  • Location:Oak Ridge, NC

Posted Mon Jun 4, 2018 6:25 PM

More to the point, if I write a program that works great in Stella, is it possible that it will be too advanced, too big, too memory-hungry for the 2600 hardware? Or would Stella force my homebrew to be within the hardware limits? 

 

Thanks.

 



#2 ZackAttack OFFLINE  

ZackAttack

    Dragonstomper

  • 748 posts
  • Location:Orlando, FL US

Posted Mon Jun 4, 2018 9:16 PM

Stella will enforce the limitations of the 2600 and whichever banking scheme you use. DASM is going to enforce ROM size too since you'll run into trouble if your code is too big to fit before the reset vector at the end of the ROM.

 

Stella is awesome, but no emulator is perfect. You do need to test on real hardware eventually. The more clever you get, especially with regard to TIA, the more frequently you need to test on real hardware. If you're serious about making a homebrew, a programmable cart such as the Uno or Harmony is a must buy.

 

You should check out SpiceWare's Collect tutorial. He'll walk you through creating a complete game in assembly with excellent explanations along the way.



#3 JeremiahK OFFLINE  

JeremiahK

    Chopper Commander

  • 217 posts
  • Location:Indiana, USA

Posted Mon Jun 4, 2018 9:25 PM

I agree, SpiceWare's Collect tutorial is the best place to start.

 

Also, I just found this site the other day: http://www.masswerk.at/rc2018/04/

It covers the creation of the recent game Refraction.  There's a lot of great information in there.



#4 stephena OFFLINE  

stephena

    River Patroller

  • 3,304 posts
  • Stella maintainer
  • Location:Newfoundland, Canada

Posted Tue Jun 5, 2018 5:39 AM

Obviously, the intent of any emulator is to do exactly what real hardware would do; no more, and no less.  That is in theory.

 

In practice, the emulation may not be absolutely perfect, and there are times when Stella allows something that wouldn't happen on real hardware, or vice versa (doesn't do something that real hardware does).  So for absolutely perfect testing, you still need to test on real hardware.  I don't see that going away anytime soon.

 

That being said, the emulator is becoming more accurate over time, and as developers continuously push the boundaries of what the 2600 can do, the emulation is improved to accommodate it.  I would say the currently released version of Stella is probably 99% compatible with programming techniques from the early years of 2600 development (70's - late 80's).  For more modern development, I would say it drops to around 96-97% or so.

 

The new sound core (coming sometime this year) is really the last major piece that is needed for near 100% compatibility.  And a few tweaks here and there for the TIA video stuff.  Personally, I can see it being very close to 100% compatible in the next year or so.  But that still doesn't mean you shouldn't test on real hardware.  It will always be final arbiter of what is correct.



#5 OldAtAtari OFFLINE  

OldAtAtari

    Star Raider

  • Topic Starter
  • 98 posts
  • Location:Oak Ridge, NC

Posted Tue Jun 5, 2018 6:09 AM

Thanks, everyone. That's what I wanted to hear. I know I'll eventually have to test it in the console, but it sounds like Stella will get me in the ballpark of what the 2600 can do, and it won't let me go crazy with a game with unrealistic requirements. So I should program for Stella and then verify on the hardware.

And both those tutorials look great to me. I wasn't expecting tutorial recommendations in this thead, but I'm happy to get them. And I need them! Thank you!

#6 Mr SQL OFFLINE  

Mr SQL

    Stargunner

  • 1,988 posts

Posted Tue Jun 5, 2018 7:15 AM

Thanks, everyone. That's what I wanted to hear. I know I'll eventually have to test it in the console, but it sounds like Stella will get me in the ballpark of what the 2600 can do, and it won't let me go crazy with a game with unrealistic requirements. So I should program for Stella and then verify on the hardware.

And both those tutorials look great to me. I wasn't expecting tutorial recommendations in this thead, but I'm happy to get them. And I need them! Thank you!

 

If you know BASIC you may like the three 10 line game tutorials on this page and the BASIC IDE:

http://relationalfra...gamesonline.htm

 

Both BASIC's are compatible with Stella but if you want to write for the flashback portable console you should test there first for best compatibility.






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