Homebrew The State of 16-Bit Emulation on the DS/DSi

[smf]

Yes that would be the best way, not sure that someone will spend time on it though...

Well certainly not at this point in the DS/DSi life. Although I wrote an 8080 emulator that ran on a commodore 64. You need an accelerator for it to be really usable, but there is one that actually makes it run too fast.

It would have to be a real passion project.

I don't know if it would be possible to leverage any of https://github.com/michalsc/Emu68

 

[DeadSkullzJr]

So as a follow-up to The State of 8-Bit Emulation on the DS/DSI post I made... here is the 16-bit counterpart.

I only spent time with 3 emulators: JenesisDS, SNEmulDS, and NEODS.

Unfortunately, there were problems across the board on all three. Let's take a dive in...

JenesisDS showed a lot of promise. The wiki for compatibility showed mostly green and the first game I played on it (Gleylancer... a fantastic Japanese Shmup) worked well enough. Speed was good! Seems to run at 60FPS which is solid. Sound was good - but I noticed that the screen resolution was really difficult to overcome. They do so with the use of the L/R shoulder button to pan left/right... or you can "follow d-pad" where if you are pressing in one direction or the other it will pan in that direction - but for fast-paced shooters this is less than ideal as you are often barreling forward into an enemy when it the screen pans. The Genesis has a native screen resolution of 320x224 so it sucks both vertically (where the DS only has 192 pixel rows) and horizontally (where the DS has only 256 pixel columns). I'd like to have seen more scaling options presented... but it's still workable. Then I tried my 2nd game - the most beloved of shooters on the system... Thunderforce IV [aka Lightening Force (sic)]. It ran fine - even the multi-layered parallax scrolling was pretty good until the first boss encounter when the game froze. I tried again... got a bit further and the game froze again... this ROM works perfectly on my PC emulator. It's a big game - maybe it's not loading right because of that. Anyway, that was it - if my 2 fav games on the system are 50/50... it's probably not going to work for me.

SNEmulDS was a bit more disappointing. There are lots of layer issues with some things showing in front of others when it's not supposed to. This causes some real jarring issues in the Axelay and Space Megaforce. The sound was also a bit of a let-down... Chrono Trigger sounded scratchy and the music would sometimes lag and play over other sounds when it shouldn't... and then there were some serious screen glitches when trying to just get through the first few scenes of that legendary RPG. I also tried Earthbound and it was better - but not convincingly so. The menus are in Japanese - but I can work out katakana well enough to navigate - but that's still not a plus. Speed was hit and miss... some stuff ran fine and other games seemed to have much more slowdown than I remember. In the end, with the glitches, it's hard to imagine I'll be using this much in the future. I don't need my emulation (especially on the DS) to be perfect... but it has to stand up to some use and abuse!

NEODS was somewhat of a surprise. Not directly supported by TWL++ but it can be made to run in DSi mode. But even in normal DS mode on a flash cart, it has good speed... many games run 80% or better of full speed. Screen scaling is an issue - it doesn't always look great. And there are some screen glitches. Also, the rom sets for this are really picky - and old... so you have to really dig to find the right ones. Still... was fun playing some Pulsar and Magical Drop III even if it was a little glitchy. You can get it to run in TWL++ mode (with a google search) which adds full speed but comes at the cost of some serious screen glitches. Sadly, it's hard to recommend this one except for a handful of games that where the screen glitches aren't a deal-breaker.

Overall, the 8-bit emulators are much better on the DS/DSi than the 16-bit counterparts. Maybe it's just too little processing power - it's a shame that there wasn't broader development for the DSi where the 2x processor could get the job done. I don't think there is any active development on these 16-bit emulators but I'd love to be proven wrong! Also, if you know of any alternatives that are easy to setup and run on the DS... I'm all ears

It would be nice if jEnesisDS got updated more, but the source code never was made available, the only option for that is to disassemble the latest version and work with that in some way, sure the process might be tedious but at least there is still a chance this could be worked on, just have to go backwards first before moving forward again lol. As for SNEmulDS, this emulator actually has been updated a few times, a revival project came to be years later but unfortunately was discontinued back in 2020, you can check the source out here, you'll need to jump to a previous commit or two to get to the full source since the latest commit doesn't have the stuff. If you plan to pick this one up eventually then you will need this according to the commit read me document. NeoDS is an interesting one for me, never actually played the NeoGeo, so for me my experience came from this, unfortunately I don't know the whereabouts of this emulator now a days, all I have is older builds sitting on a drive.

 

[Cris1997XX]

Coto is trying to improve SNemulDS, maybe you can give him a hand. But honestly, I feel like it's a lost cause. The emulator has a lot of problems, and each new update fixes or breaks something...

 

[Ajlr]

Coto is trying to improve SNemulDS, maybe you can give him a hand. But honestly, I feel like it's a lost cause. The emulator has a lot of problems, and each new update fixes or breaks something...

Yeah SNEmulDS has a lot of problems like the layers.

 

[Coto]

Coto is trying to improve SNemulDS, maybe you can give him a hand. But honestly, I feel like it's a lost cause. The emulator has a lot of problems, and each new update fixes or breaks something...

I'm not working on SnemulDS anymore, but at least now the source code is being worked on to be left on a stable state. Stable enough to warrant compatibility with games which do work on last SnemulDS 0.6a (not SnemulDSx sources, as these broke literally everything), so I kinda polished the emulator so it works in TGDS1.65. This allowed a TWL port.

Because getting to work a 16-bit emulator, stable on TWL mode while getting it to work on at least a dozen of NTR setups is really an easy task.. right? An easy example is the hardcoded memory layout used in the original sources, and as such it'd never work in TWL mode. Each emulator piece should be able to move to target memory, but of course that breaks games because CPU core is hardcoded and has its own bugs, enough to cause segfaults. The emulator has like three level of segfaults, and what I did was just to literally iron out the first two levels.

Another example would be the timing issues caused by the emulator core and the DS system synchronization. For example on 0.5 and 0.6 (not 0.6a) International Super Star Soccer Deluxe would cause SNES APU to not notify the SNES CPU core because of NDS cache issues and you'd get randomly black screens, that was also fixed 0.6b onwards. You just need to look how much games broke when moving from 0.5 onto 0.6, but I can't blame even the original programmer, nor you could.

I mean you could at least try to play and compare a few games and how they run compared to SnemulDS 0.6a to say i've literally broken the emulator. lol