Appendix B: Stack Liftand Lastx; Digitentry Termination; Disabling Operations - HP -11C Owner's Handbook Manual

Appendix B
Stack Lift and LAST X
Your HP-11C calculator has been designed to operate in a natural
manner. As you have seen as you worked through this handbook,
you are seldom required to think about the operation of the
automatic memory stack—you merely work through calculations
in the same way you would with a pencil and paper, performing
one operation at a time.
There may be occasions, however, particularly as you program the
HP-11C, when you wish to know the effect of a particular operation
upon the stack. The following explanation should help you.
Digit Entry Termination
Most operations on the calculator, whether executed as instruc-
tions in a program or pressed from the keyboard, terminate digit
entry. This means that the calculator knows that any digits you
key in after any of these operations are part of a new number. (The
(cHS], ], [EEX], and «]operations do not terminate digit entry.)
Stack Lift
There are three types of operations on the calculator, depending
upon how they affect the stack lift. These are stack-disabling
operations, stack-enabling operations, and neutral operations.
Disabling Operations
There are four stack-disabling operations on the calculator.* These
operations disable the stack lift, so that a number keyed in after
one of these disabling operations writes over the current number in
the displayed X-register and the stack does not lift. These special
disabling operations are:
* Refer to footnote, page 29.
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