Consoles are different than arcade games. Though it may seem simular it is different.
Nintendo controls.dat:
Button1=A
Button2=B
Up
Down
Left Right
Select
Start
For the most part all games (except the odd controllers like gun, pad, etc...) use that. Then it's just reading the instructions to know what each button does.
You could make some sort of dat file for that. Though for many games it's about button combinations, so it isn;t simply just labelling the buttons.