At a previous employer we generated assemblers and disassemblers for various DSP cores based on an Excel spreadsheet that the software tools team shared with the processor architects. The spreadsheet cells described the layout of the various instruction fields; this was converted with a script to an architecture description DSL, from which the assembler, disassembler, and other tools could be generated. Another DSL described the pipeline stalls and hazards, and code generated from the combined descriptions drove instruction schedulers and code checkers.