melonDS aims at providing fast and accurate Nintendo DS emulation. While it is still a work in progress, it has a pretty solid set of features:

• Nearly complete core (CPU, video, audio, ...)
• JIT recompiler for fast emulation
• OpenGL renderer, 3D upscaling
• RTC, microphone, lid close/open
• Joystick support
• Savestates
• Various display position/sizing/rotation modes
• (WIP) Wifi: local multiplayer, online connectivity
• (WIP) DSi emulation
• DLDI
• (WIP) GBA slot add-ons
• and more are planned!







Download melonDS

If you're running into trouble: Howto/FAQ
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Little news...
Mar 17th 2025, by Arisotura
Thank you all for the kind messages, it means a lot to me.

Things are still rough for me. On one hand, I'm dealing with old personal issues that I have never really addressed properly. On the other hand, I have been feeling very pessimistic about the state of the world and the future for years now, so that doesn't help. There's also surgery recovery playing into this, but that should hopefully get better with time. Anyway, I'm going to try a new type of therapy, since previous attempts haven't really helped.

As far as melonDS is concerned, there won't be much news from me for a while. I think I need a break from it. Sometimes it just feels good to focus on something else.

I could talk a bit more about the Wii U gamepad stuff, though. For now, I mainly post in threads at GBAtemp and nesdev, but I could make a kind of blog for it. I don't know... I intended to make a blog of that kind for it and other personal projects, but, you know, ADHD.

Anyway. The Wii U gamepad.

As you might already know, that gamepad is a nifty little tablet with its own processing power. It runs off an ARM9 CPU clocked at 108 MHz, with 4 megabytes of RAM. Okay, it's less powerful than the DSi, but there's something about running custom software on it that I like. It scratches a very particular kind of itch for me.

It's actually a little project I had started back in 2016, around the same time melonDS was born. Which resulted in some files for this project having melon-themed names too. Heh. Anyway, I was able to run some custom code on the gamepad, but couldn't do much beyond toggling the rumble motor -- the gamepad version of your typical 'blink a LED' embedded hello-world program, I guess. Lacking hardware documentation and proper means to upload and debug gamepad code, I was fumbling in the dark, and didn't get much done. I had made another attempt in 2022, but it also went nowhere.

Last year, I went for it again, but used a FPGA to replace the gamepad's SPI FLASH memory. In a more detailed post, I could go in details about how this was done and the clever tricks it uses, but long story short, this not only lets me easily upload code to the gamepad, but it also serves as a handy debug output.

This checkerboard pattern may not seem impressive, but it took a bunch of trial and error to get this to show up at all on the gamepad screen. This isn't the DS where the screens kinda Just Work(tm) and you can display basic stuff with some simple initialization. The gamepad requires you to initialize the LCD and video hardware before anything will be displayed.

... read more
14 comments (last by Tippick) | Post a comment
Sorry.
Feb 27th 2025, by Arisotura
I am completely burnt out.

Haven't touched melonDS in forever. Even with gamepad stuff, I'm slow.

My mental health is terrible.

Don't expect much news from me for a long while. As far as the proper 1.0 release is concerned... I don't know.

Sorry.
57 comments (last by Roald) | Post a comment
Opening the nightly builds section, finally!
Jan 28th 2025, by Arisotura
As title says, the nightly builds section is finally open, and you can access it from the downloads page.

I realized there was some missing information that was good to have (like, uh, the commit messages), so I added that into the system. Hopefully I didn't break it again :P

Other than that, sorry for the lack of updates these days. Surgery recovery plus regular winter tiredness make for an... interesting combo. I'm also caught into the WiiU gamepad stuff, so melonDS isn't seeing a lot of updates lately. We definitely have a little backlog of issues that we ought to fix before a proper 1.0 release though -- we'll get there.

There's also more revamping that needs to be done to this site, like finally updating the screenshot gallery, or adding some uploader support for us.

So much to do, so little time... (and so much ADHD)


Regardless, enjoy the nightly builds. Keep in mind that these builds are bleeding-edge and experimental, so things may not be as polished as release builds, and you may run into issues.
15 comments (last by wumpusfruit) | Post a comment
Lil' status update
Dec 9th 2024, by Arisotura
I've had surgery a couple weeks ago, as I mentioned. It went very well and I'm recovering quickly, so all is good on this front. Thank you all for your kind messages, it means a lot!

I also wanted to open up the nightly builds section, but I ran into a little issue. Basically, I made the database field for artifact IDs a regular integer, but Github's artifact IDs eventually became greater than 2147483647, which is the highest value a 32-bit signed integer can represent. Due to this, the commits since November were stored without their associated artifacts (the nightly builds).

I fixed the database structure. Now I will see if I can run a script to download the missing artifacts. Otherwise, further commits should have their artifacts downloaded correctly.

Once all that is sorted out, I will open up the nightly builds section.
16 comments (last by Salad) | Post a comment
melonDS 1.0 RC, there it is!
Nov 21st 2024, by Arisotura
We have finally released a brand new version of melonDS: 1.0 RC.

A bit of a disclaimer about this unusual version number: due to the large number of changes since 0.9.5, this version is a Release Candidate. We have done a thorough round of testing and bugfixing, but there is always the chance that further issues went unnoticed. This release will be the occasion to catch them and fix them for the actual, proper 1.0 release.

Now, the biggest changes this release brings:


Core refactor

This is the biggest change by far. We have undertaken a large and ambitious refactor of the melonDS core, in order to make it possible to run multiple instances of the emulator within one single process.

What does this change mean for end users? It means that local multiplayer is easier to deal with, since we no longer have to deal with inter-process communication. It also means that depending on your platform, local multiplayer may be more performant now.

However, much like in 0.9.5, this multiplayer mode only works when running multiple instances on the same computer. But we have another ace up our sleeve, which we'll see next.

It's also worth noting that this refactor was partly motivated by the idea of adding netplay support. While I haven't been able to get netplay working yet, the refactor has laid a very important foundation for it. We'll get there, eventually!


LAN support

... read more
61 comments (last by DC) | Post a comment
Happy birthday melonDS
Nov 8th 2024, by Arisotura
melonDS is 8 years old now. Thus, here's the appropriately colored logo for this event:



We have to a point where, well... You guess it, it's been two years since the last proper release.

melonDS has become quite a large and complex project, with many moving parts. I compare an emulator project to a tree: when you're done with the trunk, it branches off in a billion directions. That's pretty much it.

We have been through a pretty big refactor of the codebase, and that comes with its lot of issues, doubts, and so on. Was the refactor a mistake? What could we do better?

One of the major selling points was the development of netplay. Unfortunately, that's not the first time I have big ideas, big ambitions, but fail to concretize them. That's ADHD for you.

In a way, I'm also afraid of netplay. It feels like a bit of a Pandora box. I mean, it has potential for being a very cool feature, but also for being an endless source of issues. Dealing with the wifi connection issues for so long has given me a glimpse of it already. As a matter of fact, solving interesting problems is something I'm good at, but user support is not. I've had a bit of a similar experience at my last job, too.

Regardless, I still consider melonDS to be a great success.

I might try netplay later if I feel like it, but for now, I'm burnt out on that stuff.

... read more
18 comments (last by Arisotura) | Post a comment
Public service announcement
Oct 31st 2024, by Arisotura
Lately, we have seen more and more people asking us about the site at melonds.org, so I feel compelled to write a post to clarify the situation.

That site is a fake site.

It is part of a larger network of fake emulator sites (like desmume.com) that only exist to leech SEO traffic and confuse users.

The only real melonDS website is the one you are currently looking at: melonds.kuribo64.net.


What can we do?

I intend to add a splashscreen to melonDS with the URL to this site, to make things clear. The URL is also printed in the console, but since melonDS release builds don't really come with a console window anymore, well...

Other than that, spread the word, so people don't get confused.

Also: it appears that Bing (and by extension DuckDuckGo) has decided that melonds.org is the legitimate site, and has removed our site from their search listings.

So, if you can, help us fix that. Report the fake site to Bing or DuckDuckGo.

... read more
22 comments (last by Anonymous) | Post a comment
Future of melonDS
Oct 12th 2024, by Arisotura
Hello there. There hasn't been a whole lot of melonDS related activity lately.

I've been completely caught in a different, but fun project. If you have seen my Github lately, you might have an idea what it's all about. It's actually an idea I've had since 2016: hacking the WiiU gamepad to run custom code on it, and trying to figure out what kind of cool things are possible. I made attempts back in 2016 and 2022, but never really got anywhere. However, 3 months ago I felt like making a more serious attempt (namely involving a FPGA board) and actually managed to get things done. I kinda want to make a non-melonDS blog to talk about that kind of projects, too -- there would be a lot to say. This project is really challenging and intellectually stimulating, which is all I love!

Anyway, I digress.

melonDS.

I still need to finish fixing the bugs before we can release 1.0. I hope I'll manage to get myself to get there, given the way my focus and motivation works.

First, thank you all for your kind comments! It means a lot.

Next, the plans. As I mentioned before, I want to take a big break from melonDS after releasing 1.0. melonDS will be 8 years old, and that's a lot, especially for a project of mine. It has been a very good project and I've had a lot of fun, but I think I need to do other things for a while.

However, melonDS isn't going to go dead.

You might have noticed that Jakly has been contributing a lot of accuracy improvements to melonDS. The amount of research she has been putting into things like the 3D rasterizer, or lately the ARM CPUs themselves, researching all the weirdest quirks and trying to emulate them, has been astounding. Better than even I have done years ago.

... read more
27 comments (last by AlmighalX) | Post a comment
Some news...
Aug 30th 2024, by Arisotura
Uninspired title huh.

Anyway, thank you all for your kind comments, it means a lot!

I haven't been working much on melonDS lately, mostly been relaxing by working on another personal project.

As far as melonDS is concerned, my plan is to release version 1.0 by November, ideally around the project's birthday. It is going to be 8 years old, by the way. I am amazed that it has been going this far.


So here's a quick list of the things that need to be done until then:

Implementing the multi-window feature. It shouldn't be very difficult, I had already coded the required support a while ago. It's mostly matter of integrating it into the UI and ensuring everything works correctly.

Fixing up the JIT to work with multiple instances. Generic is the JIT expert over here, so that'll be for him to deal with.

Maybe fixing up LAN, if I ever manage (and if I feel more motivated to work on it).

Fixing all the issues that have cropped up during the big refactor. There's also still a bunch of code cleanup to do. We will also need a bunch of testing and QA to make sure the 1.0 release works as intended.

... read more
28 comments (last by ppk) | Post a comment
Netplay will be postponed
Aug 17th 2024, by Arisotura
It will not be part of melonDS 1.0.

The scope of this feature means it requires more development and testing time than I would be able to do before November.

You can tell I was in a really active period. I'm trying ADHD meds, again. They work, but I overestimated things, and I burnt out.

The recent wifi stuff was the straw that broke the camel's back, I guess. I mean, why did I spend so long implementing the powersaving stuff, channels, etc, in the first place? That's right, I was trying to fix games that had trouble connecting. I thought I had figured it out, I had a fix that worked well for me, but then I kept getting reports that it wasn't working. I did more of the same a few days ago, once again thinking I had a decent fix, and nope. Only makes things slightly better, or doesn't make any change. This feels utterly defeating. Like nothing I do will ever fix it.

It's kinda like when I make posts about my difficulties and all I get in the comments is "can you add feature X" "can you fix Y". I'm not a programming robot, you know.

I'm burnt out, I guess. I want to put out melonDS 1.0, but I need a big break from melonDS.
30 comments (last by HappyMan) | Post a comment
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