Section 3: Automatic Memory Stack and ALPHA Register44
Manipulating Stack Contents
The R  (roll down), R  (roll up), and X Y (x exchange y) functions allow you to review the stack contents or to move data within the stack for computation at any time. Note that R  is one HP-41C function that is not on the keyboard. It is executed from the display or assigned to a key for execution. Execution of functions from the display and assigning functions is covered in section 4.
Reviewing the Stack
To see how the R  function works, first key in the numbers 1 through 4:
Keystrokes Display    
4 ENTER   4.0000    
3 ENTER   3.0000    
2 ENTER   2.0000    
1  1 _    
So the stack now looks like this:
  T  4.0000    
  Z  3.0000    
  Y  2.0000    
  X  1 _   (Displayed)
Now press R :
Keystrokes Display    
R    2.0000    
The stack now looks like this:
  T  1.0000  
  Z  4.0000  
  Y  3.0000  
  X  2.0000  
When you press R  , the stack contents shift downward one register. The last number in the X-register rotates around to the T-register. When you press R  again, the stack contents again roll downward one register.