Introduction

This is an SDK to develop applications for Nintendo DS in C or C++.

1. Goals

To create an easy-to-use NDS software development kit based on GCC with as few dependencies as possible, and that supports as many features of the DS and DSi as possible.
To encourage developers to hack and improve the SDK by letting them have all the source code of the SDK. This also shows how easy it is to build the whole codebase. The exception is the toolchain, which is non-trivial to build. Because of that, Wonderful Toolchains is used instead of asking the users to build it themselves.
To try to keep compatibility with pre-existing C projects made by devkitARM. In theory, it should be enough to replace the Makefile of devkitARM by a Makefile of BlocksDS to build any old project, with some few exceptions. Check this guide for more details.
To document as much of the SDK as possible. For detailed information about the design of BlocksDS, check this document.
To ensure that the licensing status of all the code is correct and that the licenses used are all FOSS. This SDK is made from the work of many others that came before it and who developed FOSS libraries that can be now used by BlocksDS. This SDK must ensure that all the code remains FOSS for other people to use it in the future. For more information about the licenses used by different components, check this.

2. Features

2.1 Standard libraries

Binaries are pretty small and their baseline RAM usage is low thanks to using picolibc instead of the more commonly used newlib.
A libc with most of the features and functions you would expect in a regular environment like in a PC. For example: printf(), scanf(), fopen(), stat(), opendir(), malloc(), gettimeofday(), time() and exit().

There are versions of functions like memcpy(), memset() and memmove() that have been optimized for the CPUs of the DS. This is thanks to using ndsabi, a fork of agbabi by felixjones.

Also, argv may be provided by the environment so that programs know where they are running from (the path of the NDS file is provided in argv[0]), and any arguments pased to it if any.
It is possible to access the filesystem of DLDI devices (like the SD card of flashcarts), the SD slot of the DSi, and the filesystem embedded in a NDS ROM (NitroFS). Performance (particularly for reads) has been optimized by asie a lot. This is partly thanks to using FatFs, partly due to the DSi SD driver by profi200, and partly due to lots of additional optimizations by asie
C++ is supported, as well as libstdc++ but it hasn’t been tested as extensively as the C standard library.
There is basic cooperative multithreading support. libnds has been modified to be thread-safe. Thread-local storage support has also been added. You can define variables that are unique per thread like this:
```
__thread int my_variable = 1000;
__thread int other_variable;
```
Filesystem reads can be done from the ARM9 and ARM7. You can make the ARM9 ask the ARM7 to load files in one thread. While the ARM7 load files the ARM9 can be doing other things in other threads, so you aren’t blocked. This is always done when loading files from the SD card of the DSi, but it can also be done with DLDI devices. Most DLDI drivers can run from the ARM7 even if they haven’t been explicitly built with that in mind!

2.2 Supported DS features

All features of the 2D video hardware are supported. There are some APIs to simplify the usage of backgrounds and sprites, as well as a basic text console system based on the 2D background system.
All features of the 3D hardware are supported through an API that is similar to the one of OpenGL 1. There is a library to render 2D graphics with the 3D hardware easily, called GL2D.
There is a tool to convert graphics to the formats used by the DS: grit. The only format that it doesn’t support is the Tex4x4 texture format, but that one is supported by ptexconv.
The audio hardware is supported. There are two libraries that can be used to play music: Maxmod and libxm7. libxm7 only supports playing MOD and XM files, and it is required to use libnds to play SFXs through a basic sound API. Maxmod, on the other hand, has its own way to play sound effects and music, and it supports MOD, XM, IT and S3M files.
It is possible to record audio using the microphone of the console.
There are some helpers to use the division and square root co-processor, the BIOS functions, hardware timers, DMA, interrupt handlers, and the hardware FIFO system for ARM9 <-> ARM7 communications.
There are some helpers to setup the MPU and to manipulate the cache of the ARM9 (to clean it or invalidate it).
There is an API to access the DS cartridge ROM, as well as EEPROM chips in the cartridges that use it. It is also possible to access the filesystem of SD cards used in flashcarts.
There is an API to read the state of the buttons and the touchscreen.
There is an API to use Slot-2 peripherals such as RAM expansion cartridges, gyroscopes or tilt sensors.
There are some helper functions to decompress some formats supported by the BIOS.
It is possible to read and set the date and time of the RTC clock.
WiFi support isn’t complete. It is possible to connect to Access Points with the library DS WiFi, but it doesn’t support DS to DS WiFi communications.
ndstool supports creating NDS ROMs and define a ROM icon and banner text (in multiple languages!).

2.3 Supported DSi features

The SD slot of the DSi is supported.
The new DMA features, as well as the new WRAM memory banks, are supported.
ndstool supports animated icons from PNG, GIF, even animated GIF files.
The DSi camera is supported (thanks, asie!). It’s still quite basic, but enough to be able to take photos from the front and back cameras.
There is preliminary support for the DSP of the DSi (the toolchain is very buggy, so be very careful when using it, it’s probably not ready to be used by most developers!).
Unfortunately, none of the DSi WiFi features (such as WPA support) are supported by DS WiFi yet.