This mode also activates the the A-F keys allowing you to key in numbers in hexadecimal notation. Selecting the bin mode button forces the stack to display all numbers in binary notation. This mode also deactivates all numeric entry keys with the exception of 1 and 0. The swap key will exchange the last two entries on the stack. All computations are performed on numbers on the stack.
All computations require either one or two arguments.
If a selected computation requires two arguments and the stack contains only one number no operation is performed and the stack is left untouched. Some computation buttons are marked with X and Y arguments. In all cases X is the last entry on the stack and Y is the second to last entry on the stack. The image below shows the alternate function keys activated when the alt button is pressed.