HP HP-28S - Restoring the Stack

If you need exactly the same arguments for two or more commands in
sequence, you can execute LAST to
return copies of the arguments to
the stack for the next command.
If the commands don't require ex-
actly the same arguments,
or if the commands aren't in sequence, it's
easier to use local variables.
You can disable LAST (that is, the saving of arguments) by pressing
LAST in the MODE menu. The box disappears from the menu label,
indicating
that arguments won't be saved. This practice is not gener-
ally recommended, since
the calculator uses the saved arguments for
recovery
when an error occurs. However, if a command or program
fails because of insufficient memory, you can attempt execution with
LAST disabled. When you're done, be sure to enable LAST again by
pressing LAST a second time.
Restoring the Stack
Each time you press 1 ENTER I (or a key that performs ENTER) the
HP-28S first saves a copy of the stack
and then performs the specified
actions.
If you're dissatisfied with the results, you can restore the
saved stack by pressing .1 UNDO I. Note that UNDO affects only the
stack-it doesn't undo changes to user flags or user variables. For an
example using .1 UNDO I, see HIf You Execute the Wrong Function" on
page 47.
You can disable this feature by pressing UNDO in the MODE menu.
The box disappears from
the menu label, indicating that the stack
won't be saved. To enable this feature again, press . UNDO a second
time.
180 19: The Stack