HP HP-28S User Manual

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

HP HP-28S Specifications

General

Introduced	1988
Memory	32 KB
Number of Digits	12
Type	Scientific Calculator
Manufacturer	Hewlett-Packard (HP)
Display	LCD
Processor	Saturn
Programming	RPL

Summary

HP-28S Advanced Scientific Calculator Owner's Manual

Part 1: Fundamentals

Introduces basic operations, calculator features, and core concepts.

Getting Started

Covers initial setup, basic operations, and calculator overview.

Doing Arithmetic

Explains methods for performing calculations using stack and expressions.

Part 2: Summary of Calculator Features

Objects

Describes fundamental data types, symbolic operations, and programming elements.

The Command Line

Explains input methods, cursor control, and command entry.

The Stack

Reviews stack concepts and commands for manipulating objects.

Part 3: Programming

Program Structures

Covers conditional logic, loops, and error handling in programs.

Conditional Structures

Explains testing conditions and making decisions within programs.

Definite Loop Structures

Details structures for executing code a specific number of times.

Appendixes & Indexes

Appendix A: Assistance, Batteries, and Service

Provides troubleshooting, battery info, and service details.

Answers to Common Questions

Addresses frequent user queries and common calculator issues.

Appendix B: Notes for HP RPN Calculator Users

Highlights differences for users familiar with RPN calculators.

Appendix D: Menu Map

Lists commands by menu, with descriptions and page references.

Contacting Hewlett-Packard