Yes, so the author is loopy. he has to be if he's making a SNES emu...lol.
Anyway, that pocketheaven thread brought up a great issue: the SNES controller has 6 buttons, GBA has 4.
However, you gotta remember something. There were very few games that required the use of all 6 buttons. I mean, a lot of SNES games didn;t use all the buttons--so a lot of the buttons were used again. In some games, X did the same as A or B, and Y, vice versa.
So...it is possible, and I can't wait.