# research

## DS / DSi emulators

wanted features:

- **DS and DSi version emulation (DSi for later)**
  
  DS version of pictochat can still receive images with rainbow drawings, but
  doesn't support sending
- **firmware booting**
  
  the phat DS and DS lite's firmware had pictochat built-in instead of as a
  standalone app like on the DSi. to launch pictochat, firmware booting must be
  possible.
- **local multiplayer network emulation**
  
  required for testing sending and receiving
- **local multiplayer packet capture**
  
  required for reverse engineering the packet format
- **local multiplayer packet injection**
  
  required for testing forged packets
- **open source**
  
  DIY packet injection anyone?
- **linux-compatible**
  
  just a preference
- **debugging (ideally using GDB or similar interface)**
  
  if all else fails, reading and/or injecting packets into memory using a
  debugger might be the only option for testing forged packets. a debugger
  could also help with reverse engineering the decoding process of a pictochat
  packet/message

### [DeSmuME][desmume]

- phat ds only
- no firmware booting
- no local multiplayer emulation
+ open source
+ cross-platform
- no debugger

DeSmuME is focused on high quality/performance emulation for single player
titles, and actively rejects requests for WiFi emulation.

### [melonDS][melonds]

+ ds and (experimental) dsi support
+ firmware booting support
+ local multiplayer emulation
+ allows patched-in or real network packet capture using loopback network
  adapter and wireshark
+ loopback network adapter also (probably) allows injecting forged packets
+ open source
+ cross-platform
- no debugger

melonDS is a very new emulator that is still actively being developed. melonDS
is focused on accurate emulation and is the only one on this list with
sufficiently advanced local multiplayer emulation.

### [no$gba][nogba]

+ supports DS and DSi games
+ firmware booting support
- no local multiplayer emulation
- closed source
- windows only
+ very advanced debugger

[toolchaingenericds]: https://bitbucket.org/Coto88/toolchaingenericds/src/master/
[nogba]: https://problemkaputt.de/gba.htm
[melonds]: https://melonds.kuribo64.net/
[desmume]: https://desmume.org/

## MelonDS hacking

source: <https://git.pipeframe.xyz/fork/melonDS>

### Findings

- melonDS @ Config > Wifi settings "Local multiplayer features do not use the same network protocols as online play"
- comment @ src/Wifi.cpp:46 "multiplayer host TX sequence"
- references to `RFTransfer_Type{2,3}` @ <https://www.problemkaputt.de/gbatek.htm#dswifirfchip>
- nintendo ds ni-fi protocol @ <https://web.archive.org/web/20090202194241/http://masscat.afraid.org/ninds/proto_info.php>