An assembler for the legendary 6502 processor and it's derivatives
Blazing fast and correct x86/x64 disassembler, assembler, decoder, etc
Assembles M6800 and 6801 assembly language source code. (and Forth)
Japheth's assembler, JWasm
miniasm is a short bytecode based assebler, interpreter and compiler
powerpc disassembler/assembler