Section 3: Automatic Memory Stack and ALPHA Register40
...the result is placed in the X-register and is seen in the display. The contents of the stack registers now look like this:
  T  0.0000    
  Z  0.0000    
  Y  0.0000    
  X  0.2000   (Displayed)
The Display and ALPHA Register
We have just seen how you can execute a function and how the result is placed in the X-register and seen in the display.
But if you are in ALPHA mode, any characters you key in are placed into a special ALPHA register als well as the display. The ALPHA register is separate from the automatic memory stack. The automatic memory stack is not disturbed when you key in ALPHA characters.
To see what is in the ALPHA register, simply place the HP-41C into ALPHA mode. In ALPHA mode, the ALPHA register is always displayed.
The ALPHA register can hold up to 24 characters, 12 more than the display. In any combination of full characters and periods, colons and commas, the largest number of characters you can place in the ALPHA register is 24.
When you key in a string of ALPHA characters longer than the display (12 characters), the HP-41C automatically ‘‘scrolls’’ the characters through the display to the left. If at any time you wish to see the complete contents of the ALPHA register, simply press g AVIEW (ALPHA view) in ALPHA mode.
Try it now:
Keystrokes Display    
SCROLL EXAM  SCROLL EXAM _   Watch how the HP-41C scrolls
P  CROLL EXAMP _   characters off to the left of the display.
g AVIEW   SCROLL EXAMP   AVIEW lets you view the entire
   CROLL EXAMPL   string any number of times.
g CLA      Blanks the display.
ALPHA   0.2000   The X-register is again displayed.
The APPEND function ( g K in ALPHA mode) enables you to build on to a string in the ALPHA register. You can add characters to a string already in the ALPHA register by placing the HP-41C into ALPHA mode, pressing APPEND ( g K) and then key in the desired additional characters.