melonds-ds/README.md

melonDS DS

An enhanced remake of the melonDS core for libretro that prioritizes standalone parity, reliability, and usability.

Getting melonDS DS

You can download and install melonDS DS through RetroArch's built-in core downloader where supported. If you'd like to try a development build or can't use the core downloader, you can get the latest release of melonDS DS from this repo's Releases, or the raw build artifacts from here.

Installation

Installation instructions may vary depending on your chosen libretro frontend.

RetroArch

You can install melonDS DS through the built-in core downloader where supported. If your build of RetroArch doesn't include it (e.g. Steam) or if you want to use a development build, you can install it RetroArch manually like so:

1. Place melondsds_libretro.dll (or .so or .dylib, depending on the platform) in RetroArch's cores directory.
2. Place melondsds_libretro.info in the same directory as the other .info files, which is usually cores or info depending on the platform.

Using melonDS DS

Usage instructions may vary depending on your chosen libretro frontend.

RetroArch

Playing Nintendo DS Games

1. Start RetroArch.
2. Scan your Nintendo DS game library with the Import Content menu to build a playlist if you haven't already.
3. Load a Nintendo DS game from the playlist. If you have the legacy melonDS core installed, you may need to select melonDS DS explicitly.

Important

If you have ROM hacks or homebrew, you may need to manually add them to the playlist with the Manual Scan submenu.

Installing Nintendo DS BIOS

melonDS includes built-in BIOS and firmware replacements that work with most games. However, additional system files may be required for certain features or games to work properly.

You can place your system files in RetroArch's system directory or in a subdirectory named melonDS DS. Name the system files as follows:

• DS ARM7 BIOS: bios7.bin*
• DS ARM9 BIOS: bios9.bin*
• DS Firmware: Anything, pick an image in the core options
• DSi ARM7 BIOS: dsi_bios7.bin*
• DSi ARM9 BIOS: dsi_bios9.bin*
• DSi Firmware: Anything, pick an image in the core options*
• DSi System NAND: Anything, pick an image in the core options*

*Required for DSi mode.

Game Boy Advance Connectivity

The steps for loading a Game Boy Advance ROM are a little more involved. Native BIOS files are not required.

1. Load the melonDS DS core using the Load Core menu.
2. Enter the Subsystems menu and select Load Slot 1 & 2 Boot.
3. Select a Nintendo DS ROM, a Game Boy Advance ROM, and optionally a Game Boy Advance save file (in that order).
4. Start the game.

This combination of ROMs will appear in your History playlist, so you won't have to repeat this process every time you want to play.

Note

melonDS can load Game Boy Advance ROMs and save data for the purpose of Slot-2 connectivity, but it cannot actually play GBA games. Use a GBA core instead.

New Features

Enhancements over the legacy melonDS core include:

Standalone Parity

Unlike most other libretro cores, melonDS DS is not a fork of an existing code base. It uses standalone melonDS as a statically-linked dependency, which means that large changes and merge conflicts are less of an issue. As a result, improvements to standalone melonDS are much easier to integrate!

Wi-Fi Support

Wi-Fi is fully emulated on all platforms!

For your convenience, you can choose from one of several preconfigured servers in the core options menu, with Kaeru WFC being the default.

If there's another server you'd like to use, you can set its DNS address from within the emulated console's Wi-Fi settings menu.

Note

Do not confuse this with local multiplayer. melonDS DS does not support emulating local wireless at this time.

Homebrew Save Data

The legacy core does not support save data for homebrew games. However, melonDS DS does!

melonDS DS looks in the system/melonDS DS directory (i.e. alongside the BIOS files) for a homebrew SD card image named dldi_sd_card.bin. If one doesn't exist, a virtual 4GB SD card will be created if necessary. See the core options for more information.

Note

melonDS DS does not support savestates for homebrew games.

Microphone Support

melonDS DS supports libretro's new microphone API, allowing you to use your device's microphone for Nintendo DS games!

Note

This feature requires support from the frontend. The latest stable release of RetroArch includes microphone support on several platforms.

Screen Rotation

melonDS DS fully supports rotating the emulated DS left, right, and upside-down! Now you can play games that were meant to be played sideways, such as Brain Age.

Enhanced Screen Layout Options

The legacy melonDS core supports multiple screen layouts, but they can only be switched out through the core options menu. This is inconvenient for games that use different layouts.

melonDS DS allows you to cycle through up to 8 screen layouts (including rotations) at the push of a button!

Streamlined DSiWare Installation

melonDS does not support direct-booting DSiWare at this time; you need to install DSiWare games to a NAND image, then start them from the DSi menu when you want to play.

But melonDS DS streamlines this process!

• When you select a DSiWare ROM, it's temporarily installed on the NAND and removed when you exit the core.
• Title metadata is automatically downloaded from Nintendo's servers and cached locally for later.
• When a DSi game is loaded, the DSi menu will boot with the temp-installed game selected.

Other Niceties

• Battery Support: melonDS DS uses libretro's new power state API to reflect your device's power status (battery level, charging status, etc.) in the emulated console! Requires support by the frontend.
• Selectable NAND and Firmware Images: You don't need to hard-code a specific name for your firmware or NAND images! Just place them in system/melonDS DS (or local equivalent) and pick them from the core options.

Missing Features

These features have not yet been implemented in standalone melonDS, or they haven't been integrated into melonDS DS. If you want to see them, ask how you can get involved!

• Local Wireless: Upstream melonDS supports emulating local wireless multiplayer (e.g. Multi-Card Play, Download Play) with multiple instances of melonDS on the same computer or on the same network. This feature is not yet integrated into melonDS DS.
• Homebrew Savestates: melonDS has limited support for taking savestates of homebrew games, as the virtual SD card is not included in savestate data.
• DSi Savestates: Nintendo DSi mode does not support savestates. This implies that rewinding and runahead are not supported in DSi mode.
• DSi Direct Boot: Direct Boot does not support DSiWare games at this time. They must be installed on a NAND image, and they must be started from the DSi menu.
• Game Boy Advance Emulation: melonDS can load Game Boy Advance ROMs and save data for use by compatible Nintendo DS games, but it cannot actually emulate the GBA. GBA emulation is not within the scope of melonDS; use a GBA emulator instead.
• Slot-2 Accessories: melonDS currently supports the solar sensor, Memory Expansion Pak, and Rumble Pak. melonDS DS has not yet integrated support for these accessories.
• GDB Stub Support: melonDS recently gained support for debugging emulated DS games with GDB. This is a low priority for melonDS DS, since libretro frontends are typically used for playing games. However, I may integrate it if there's enough demand.
• DSi Camera Support: Standalone melonDS supports emulating the DSi's cameras. Support in melonDS DS is planned, but has not yet been integrated.
• OpenGL Compute Shader Renderer: melonDS introduced a new renderer that uses OpenGL compute shaders, enabling the accuracy of the software renderer with the upscaling of the legacy OpenGL renderer. Support has not yet been integrated into melonDS DS.

Compatibility

Games

melonDS DS is compatible with all games that melonDS supports, unless otherwise noted in the Missing Features section. If this is not the case, please report it.

Frontends

melonDS DS primarily targets RetroArch, but you can use it with most libretro frontends. If you encounter problems using this core with other frontends, please report them! Support is not guaranteed, but I'll do the best I can.

Platforms

melonDS DS will run on the following platforms, assuming it's used with a frontend that also supports them:

• Windows (x86_64)
• macOS (x86_64 and arm64)
• Linux (x86_64 and arm64)
• Android (arm64)
• iOS (arm64)

Available features may vary depending on the platform and frontend.

The legacy melonDS core has builds for the Nintendo Switch and for 32-bit versions of the above platforms, but melonDS DS will not support these platforms unless there's enough demand.

Building

See the contributor's guide for instructions on building melonDS DS.

About the Name

Various games received enhanced remakes or ports to the Nintendo DS, including such gems as:

• Super Mario 64 DS
• Ridge Racer DS
• Brothers in Arms DS
• Mega Man Battle Network 5: Double Team DS
• Diddy Kong Racing DS

What do these games have in common? They're all remakes or enhanced ports with a suffix of "DS"!

I see this core as an enhanced remake of the legacy melonDS core, so I wanted to embody that in the name. Put differently, if I had given the DeSmuME core a similar treatment then I would've named it "DeSmuME DS"!

Special Thanks

• The melonDS team for making a great emulator and for their help on Discord.
• The libretro team for making a great app, for their help on Discord, and for fixing RetroArch bugs that affected melonDS DS.
• Everyone who's ever reported a bug, for their role in ensuring a polished product.
• Nintendo, for all the memories.

Disclaimers

This project is not affiliated with, developed by, or endorsed by the melonDS team or by Nintendo.