No no don't use ==
It's
IF BUTTON(1) AND #A THEN GOTO @OP1
Think of the variable BUTTON(1) as a binary number
It is stored with 31 ones and zeros
Each 1/0 represents a button being pressed
Say the 2nd position is the A button, so #A is always equal t
000000000000000000000000000000000010
In binary
Now if you add that AND mask to the original button it'll work just as expected
Using == will check if ONLY button A is pressed, if any other button on the 3DS is pressed, it won't think A is pressed also
AND allows multiple buttons because it only checks 1 position in binary, not all the button positions