Here in 2024, writing new games for the venerable Atari 2600 game console is easier than ever, with plenty of emulators and toolchains to convert your code into ready-to-load ROMs. Yet what is easier than diving straight into 6502 assembly code without even having to download or set up a toolchain? That’s where [Henry Schmale]’s fully in-browser Atari IDE and associated emulator (using the Javatari project) comes into play.
As [Henry] explains in a blog post, the main goal was to get a project working in Emscripten, the LLVM-based toolchain to create WebAssembly binaries with. The target of this became DASM, the macro assembler for a range of 8-bit MPUs, including the 6502. In the blog post [Henry] describes the general procedure for how he compiled and integrated DASM, as part of creating the earlier linked Atari 2600.
In this IDE a number of example programs are provided, which can be selected, assembled and run in the integrated Javatari instance. Beyond this you can write your own custom 6502 ASM, of course, but at this point you may be interested in taking things further with the versatile Stella emulator that can even run on platforms which you’d be hard-pressed to get a browser running on, never mind Chromium.