X816 is an assembler that generates machine code for the Super NES, or more specifically the 65816. X816 is based mainly on the assemblers seen on the C64/128 but with a few additions to bring it up to speed for the SNES.

X816 supports the complete 65816 instruction set and all of its addressing modes. As well, a set of assembler directives are included to make the programmers job a bit more easier. X816 will take any source code stored in a standard text file and generate binary code.

It is also a NES6502 and SNES65816 cross assembler.