If I recall correctly, the article in question was just "we have now dumped the firmware from all known SNES co-processor chips". The first SNES co-processor c

If I recall correctly, the article in question was just "we have now dumped the firmware from all known SNES co-processor chips". The first SNES co-processor chip, the DSP-1, was based on a weird NEC DSP architecture, and if I recall correctly the part-number was figured out from markings on the chip die, and digging through NEC spec-sheets looking for things that approximately matched the chip's known capabilities. The instruction set and encoding was puzzled out by hand. Luckily, DSP-2, DSP-3, and DSP-4 all used the same NEC DSP core, just with different firmware, so the same emulator could be used for all of them. The ST010 and ST011 used a slightly different NEC DSP core, so they required a little more work, but after handling the DSP-1 they weren't too difficult. The ST018 was incredibly daunting to begin with, since its firmware was much larger than all the other co-processors, and there were no identifying marks on the CPU die and no product sheets to dig up. As a last ditch effort, somebody just opened up the firmware in a hex editor and tried to figure out the instruction encoding from first principles... and eventually they said "that looks familiar", and sure enough it turned out to be the most popular CPU architecture on the planet.