Stella is a freely distributed multi-platform Atari 2600 VCS emulator; originally developed for Linux by Bradford W. Mott, it is now maintained by Stephen Anthony. Stella allows you to enjoy all of your favorite 2600 games once again by emulating the 2600's hardware with software. Stella is written in C++, which allows it to be ported to other operating systems and architectures. Since its original release Stella has been ported to AcornOS, AmigaOS, DOS, FreeBSD, Linux, MacOS, OpenStep, OS/2, Unix, and Windows, as well as consoles such as Sega Dreamcast, GP2X, Nintendo DS and Playstation Portable (among others).
Here are changes presented in 3.6.x
+ Extended FA2 bankswitch scheme to handle 28K ROMs (in addition to the previously supported 24K ROMs).
+ Added support for 2600-daptor II device, including native support for 7800 controllers, BoosterGrip and Keypad controllers. Special thanks go to Tom Hafner for a complimentary test sample of this device, and also for donating a BoosterGrip controller.
+ Added ability to dynamically swap the port order of Stelladaptor/ 2600-daptor devices with the 'Control-1' key combo (useful if you have only one 2600-daptor and want to use it as a left port normally, but as a right port for Star Raiders, etc).
+ Added CompuMate bankswitching/controller support to the emulation core; the Spectravideo CompuMate ROMs (NTSC and PAL) now work. Frequently used keys on the CompuMate are directly mapped to your keyboard (ie, Func-Space for backspace is mapped to Backspace, etc). Loading/saving from the cassette player is not yet supported, and will come in a future release.
+ Fixed bug in BoosterGrip controller emulation; the functionality of the booster and trigger buttons was reversed. Related to this, renamed these actions in the Event Mapping dialog to be more clear.
+ Reverted to SDL 1.2.14 for the Windows 98/2k release, since SDL 1.2.15 isn't supported in that environment.
+ Updated included PNG library to latest stable version.
Check out official website for further information and latest version of emulator.