What are the steps that the calculator follows when using fnInt()?

What are the basic steps that the TI-83 calculator follows when using fnInt()? For example, when doing the quadratic formula, you can say this:

Ask and get input from user, store in variable A.

Ask and get input from user, store in variable B.

Ask and get input from user, store in variable C.

Display the opposite of B plus the square root of [B^2-(4*A*C)] and then divide the whole thing by 2*A.

Display the opposite of B minus the square root of [B^2-(4*A*C)] and then divide the whole thing by 2*A.

Pause the screen

Clear variable A.

Clear variable B.

Clear variable C.

Clear the screen.

Stop.

It must be something a TI-83 is capable of doing.