Homebrew Stella-DS Improved

[raxadian]

You will need a DSi running at the 2X CPU rate for these ARM-assisted games to run anywhere near full speed.

I do have a New HD 2DS but Twilight menu can't get past DSi speed I think?

 

[wavemotion]

I do have a New HD 2DS but Twilight menu can't get past DSi speed I think?

I run most of my DSi units with TWL++ and they all run at 2X the CPU and have access to the extra memory.

The limitation is not on Twilight Menu++ but with specific setups. For example, running with an R4 or similar card tends to run in DS compatibility mode.

Anyway, the easiest way to tell what mode you are in is to try loading any Atari game within the StellaDS ROM selection by pressing and holding X and tap A (while holding X). It will bring up a mini-debugger. It will tell you what mode you are in:

Here is my DSi (original non XL/LL) that launched StellaDS via Twilight Menu++ and you can see it detected 134MHz and 16MB of memory for the enhanced DSi mode.

Well... I guess there is an even easier way... run 2600 Space Rocks and it will either run full speed (meaning you are running at the faster enhanced CPU speed) or run so sluggishly as to be unplayable (DS compatibility mode).

 

[wavemotion]

V7.6 : 25-Aug-2024 by wavemotion-dave

• Fixed config setting of RAM randomized vs clear.
• Fixed AR (Starpath/Supercharger) games to prevent memory overwrite.
• Big improvement to Starpath Supercharger (AR) cart rendering for 4-7 frames of improvement.
• Numerous comment cleanups and other minor refactors to improve the codebase.

Finally got the time to read through the AR Starpath/Supercharger banking logic to really understand what's going on and what games do to write the large chunk of RAM on the expansion module. With that knowledge, I was able to refactor my AR cart driver and get almost 10% speed across the board for AR games! This should render everything full speed on the DSi for the Starpath/Supercharger games with the exception of Escape from the Mindmaster which runs mostly at full-speed with occasional frame drops when it has to render a long 3D hallway (won't affect gameplay any).

Not sure on the DS-Lite... never thought AR games would be playable but I suspect Communist Mutants From Space and Rabbit Transit might both be playable (and both are awesome).

 

[wavemotion]

Version 7.7 of StellaDS has been released: https://github.com/wavemotion-dave/StellaDS

V7.7 : 24-Nov-2024 by wavemotion-dave

• Improved 'Wave Direct' sound to help with digitized speech effects of Quadrun, Berzerk VE, Open Sesame, Pitfall II, Stella's Stocking, etc.
• Tweaked handling of the new Champ Games - Tuthankham.

The big change here is the improved Wave Direct driver. I was only able to squeeze a little bit of improvement for the heavy hitting games that utilize digitized speech effects (yes, I'm looking at you, Draconian with your boundary-pushing shenanigans!

) but there is major improvement for the games that allow the poor little DSi/XL/LL to have a few spare CPU cycles to smooth things out. So games like Quadrun and the various Berzerk Voice Enhanced games will now sound much nicer with the voices being fairly clear and distinct. The music in Pitfall II is less scratchy - still not perfect, but a step in the right direction.

The older DS/Lite units will not see these benefits as there just isn't enough CPU to do this extra audio processing.

 

[wavemotion]

https://github.com/wavemotion-dave/StellaDS

V7.8 : 30-Nov-2024 by wavemotion-dave

• Further tweaks to the improved 'Wave Direct' to prevent audio gaps.
• First pass at allowing 'Wave Direct' for DS-Phat/Lite (only for simple games like Quadrun, Berzerk VE and Open Sesame).
• Tweaks to the DPC audio driver for improved Pitfall II music.
• Added support for some of the Voice Enhanced Berzerk hacks such as DrVsDaleks.
• Improved Meltdown emulation - added hack for NUSIZ0/1 to improve screen rendering. Not perfect but closer...
• Fixed Pole Position lap counter so it shows correctly.
• Fixed Grand Prix graphical glitch on rocks/scenery (Player Reset timing).
• Apply RSYNC improved TIA handling across the board (was only being applied to select games).

 

[wavemotion]

https://github.com/wavemotion-dave/StellaDS

V7.9 : 04-Dec-2024 by wavemotion-dave

• Fix so holding shoulder buttons on Bumper Bash does NOT invoke the screen snapshot.
• Fix for bumper bash right bumper position so it now shows correctly.
• Improved GI Joe Cobra Strike snake graphics so it's much closer to the way a real TIA chip would draw it.
• Fix for Labyrinth (AR) graphical glitches at top/bottom of walls.
• Improved difficulty switch handling so startup values for games like Asteroids works correctly.
• Improved RIOT timer emulation - Acid Drop, Panda Chase, Zoo Fun and a few other PAL roms now work.
• Improved keyboard/keypad emulation so games like Alpha Beam with Ernie, Oscar's Trash Can Race and Magicard now work.
• Improved emulation of Starpath Supercharger (AR) games (Dragonstomper is random) and support smaller game loads (Cubis now runs).
• Fixed Casino paddles (correct paddle emulation so you can select all card positions in game variation 4).
• Internal cart database updated to Romhunter v19 (full NTSC with select PAL titles).
• Fix for save/load states on CDFJ+ carts (Gorf and Turbo Arcade will now save/load correctly).
• Wave Direct improvements - applying the same logic for all games that utilize digital speech and improving sounds.
• Added new Stretch-X config option to stretch the screen horizontally (you can use offset/stretch to fill the screen for some Activision games which purposely hide the HMOVE blanks on the left side of the screen).
• Pressing and holding the Game Select and Game Reset buttons now keeps them depressed until you let up your finger.

Lots of tweaks and improvements across the board as I now focus less on new features and more on getting as many games fully playable as possible on the little handheld. One change I don't know if people might use is the ability to shift the X position of the screen and stretch it... this is mainly useful for some of the Activision games that purposely hide the HMOVE bars on the left and sometimes we're left with 8 pixels of 'dead space' on the left... which is fine for TV use but on the DS handheld, those 8 pixels are precious with such a small resolution screen. So now you can, if you wish, offset by 8 pixels and stretch the display across the screen. This results in a slightly elongated image... but if you're more interested in covering as much of the little screen as possible, it's something you can try experimenting with. I think that I'll be utilizing it for some games - and really, that's the main reason I add any new features at this point

If you go into Configuration and hit SAVE, it will save these screen position/scaling on a per-game basis.

vs

 

[wavemotion]

8.0 : 09-Dec-2024 by wavemotion-dave

• Added music fetchers for more complete Chetiry (CTY) emulation. Save state works with CTY. Use the 60K Chetiry rom for music.
• Fixed holding RESET (DS Start button) and SELECT (DS Select Button) when loading a game. This allows you to do things like the Double-Shot trick in Space Invaders.

 

[wavemotion]

It's been slightly more than a year!

https://github.com/wavemotion-dave/StellaDS


8.1 : 14-Dec-2025 by Dave Bernazzani (wavemotion)

• Added new Favorites system so you can LIKE/LOVE any game - press SELECT on the Game ROM loading screen.
• TIA optimizations for another frame of improved performance.
• CPU optimizations for another frame of improved performance.
• Thumbulator optimizations for the LDR3 instruction to help some CDFJ games.
• Most VBLANK and HBLANK optimizations now removed in favor of improved accuracy (improved performance allows us to ditch most of this).
• Refactor memory to buy back almost 250K of DS RAM for future expansion.

 

[djleviticus]

Wow thanks Dave. Real nice update

 

[raxadian]

Refactor memory to buy back almost 250K of DS RAM for future expansion.

Cool.

Now I have to remember what was this thing for.

Ah right Atari 2600 games.

 

[esv_83]

I have tried the Atari ST StyxDS emulator, and I see that some games work but very slowly. Could you improve this emulator?

 

[wavemotion]

I have tried the Atari ST StyxDS emulator, and I see that some games work but very slowly. Could you improve this emulator?

Being superstitious, not sure I want to sign-up for a 13th emulator

I also didn't see any obvious source code available. Anyone know if it's out there?

 

[CrashMidnick]

Being superstitious, not sure I want to sign-up for a 13th emulator

I also didn't see any obvious source code available. Anyone know if it's out there?

This is emulator is based on Castaway and is very bad. Better start from scratch (from castaway source) IMHO.

For sure it will be a challenge and only DSi will be able to run it at pretty good speed (based on what I have seen with DCaSTaway).

Howerever, I think that the DSi deserves such an emulator. Maybe if you join your skills with @FluBBa for the sound part, the magic can happen

 

[Cris1997XX]

The Atari ST might be weaker than an Amiga 500, but it's still way more demanding compared to even the Commodore 64. He should work on a Sega Mega Drive or PC Engine emulator first

 

[wavemotion]

PC Engine emulator first

We already have an unbelievable PC Engine emulator courtesy of FluBBa. Even plays my beloved Gates of Thunder on CD! (via ISO image).

I think I'll leave the 16-bit machines to more talented people

 

[CrashMidnick]

The Atari ST might be weaker than an Amiga 500, but it's still way more demanding compared to even the Commodore 64. He should work on a Sega Mega Drive or PC Engine emulator first

Nitrografx is already very good, no need to dev a new one. We already have a good Megadrive emulator, I do not thnink it would be possible to have a better one without huge work. Even picodrive runs at 40fps on dstwo.

 

[Cris1997XX]

Nitrografx is already very good, no need to dev a new one. We already have a good Megadrive emulator, I do not thnink it would be possible to have a better one without huge work. Even picodrive runs at 40fps on dstwo.

JenesisDS is decent, it runs well for being an old emulator meant to run on the stock DS. But you could do a lot more on the DSi, like adding support for bigger games, better audio emulation and making the framerate more stable

 

[wavemotion]

https://github.com/wavemotion-dave/StellaDS

8.1a : 24-Jan-2026 by Dave Bernazzani (wavemotion)

• New NTSC 'True-Sync' to reduce tearing and other video artifacts from screen rendering on the DS/DSi.

A small change (code-wise) but a significant one. I finally got around to syncronizing the emulation rendering with the DS NTSC Vertical Blank. This helps reduce visual artifacts that would show up on a few games - games like Barnstorming with the horizontal scroll you would sometimes see a tearing effect on the red barns as they rendered on the DS out of sync with the emulation. This change now starts emulating the first scanline while the DS is drawing near the bottom of the screen with the goal that for 95% of the games, the DS render and the Emulation render will not cross paths.

I'm working on a similar improvement for PAL games (there is a way to trick the DS into refreshing 50 times per second) - but for now, this True-Sync only happens for NTSC.

It needs a bit more testing before I can put out an official 8.2 release but you can grab the nightly build to try it.

 

[wavemotion]

https://github.com/wavemotion-dave/StellaDS

8.2 : 12-Apr-2026 by wavemotion-dave

• New NTSC (60Hz) and PAL (50Hz) 'True-Sync' to reduce tearing and other video artifacts from screen rendering on the DS/DSi.
• Improved accuracy on SB (SuperBanking) carts.