Some basic questions on Emulator Stella

[Keatah]

I've just a few ???'s about Stella. And forgive me if they've been asked before.

 

1- Will Stella ever be expanded to include 7800 compatibility? To me on layman's terms, the systems seem a little similar. And certainly from a gamer/hobbyist viewpoint, VCS fans are taking a liking to the 7800 and they are tending (now) to ask that if any new VCS products hit the market if 7800 games will also work. Has it ever been discussed?

 

2- How does the frying work in Stella? I mean like does it just randomize some key values? All values? Values of what - I don't know! I'm not a dev. I was also thinking about if there could be options added to the frying, like say hit just the data lines, or address lines? Or temporarily pull one or more of something out of circuit. Just a thought. And if the frying feature is left alone, maybe there could be ONE mod done to it.

 

Since McDonald's upped their prices again in my area, $8.50 for a BigMac meal now, maybe the fry button could eject real fries from the USB port or something.

 

3- How about a 1-key "hot rewind"? This would basically cover the past 10 seconds and always be ready on-demand. Unless it's in there already. Must read the manual.

Edited July 21, 2018 by Keatah

[+SpiceWare]

From Console.cxx

/* Original frying research and code by Fred Quimby.
   I've tried the following variations on this code:
   - Both OR and Exclusive OR instead of AND. This generally crashes the game
     without ever giving us realistic "fried" effects.
   - Loop only over the RIOT RAM. This still gave us frying-like effects, but
     it seemed harder to duplicate most effects. I have no idea why, but
     munging the TIA regs seems to have some effect (I'd think it wouldn't).
   Fred says he also tried mangling the PC and registers, but usually it'd just
   crash the game (e.g. black screen, no way out of it).
   It's definitely easier to get some effects (e.g. 255 lives in Battlezone)
   with this code than it is on a real console. My guess is that most "good"
   frying effects come from a RIOT location getting cleared to 0. Fred's
   code is more likely to accomplish this than frying a real console is...
   Until someone comes up with a more accurate way to emulate frying, I'm
   leaving this as Fred posted it.   -- B.
*/
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
void Console::fry() const
{
  for(int i = 0; i < 0x100; i += mySystem->randGenerator().next() % 4)
    mySystem->poke(i, mySystem->peek(i) & mySystem->randGenerator().next());
}

---

So every Zero Page address (TIA and RAM) is PEEKed to get its contents, the results of which are then ANDed with a random number, and finally POKEd back.

The ANDing means individual ON bits can be turned OFF, but OFF bits will never be turned on.

[Keatah]

Got it.

[+stephena]

1. Not likely, unless someone with 7800 experience steps forward to do so. I've never owned a 7800 until the past few years, so I really have no experience with it. And 2600-compatibility aside, the 7800 and 2600 are really two different machines.

Spice already answered this.

See 'Time Machine' functionality, which was a major release point for version 5.1. The fact that it got very little feedback despite it being a decade-long feature request makes me wonder if many people actually saw the changelog for 5.1 and actually tried it. Or maybe it's not as anticipated feature as I originally thought.

[Keatah]

Gotcha. In thinking about #3. I guess I thought it might be (somehow) implemented differently. Well no big deal.

 

Feature desirability comes and goes. What was once a hot item 2 years ago may simple be "meh" today.

Edited July 22, 2018 by Keatah