Multiple Computer and Console Emulator. It emulates over 100 different systems and even more derivatives of them. MESS is available for AmigaOS, Digita, DOS, MacOS, RISC OS, Unix, and Win32, and is open source.
The definitive HuC6280 Assembler package for DOS, Linux and RiscOS. Includes thorough technical information about PCE/TGX internals, as well as in-depth tutorials on coding sprite routines. Maintained by David Michel.