United States Patent 4,059,750
General Purpose Calculator Having Selective Data Storage, Data Conversion and Time-Keeping Capabilities
Nov. 22, 1977
Inventors:
- Peter D. Dickinson, Monte Sereno, Calif.
- Thomas E. Osborne, San Francisco, Calif.
- France Rode, Los Altos, Calif.
- Allen J. Baum, Los Altos, Calif.
Assignee: Hewlett-Packard Company, Palo Alto, Calif.
Appl. No.: 566,143
Filed: Apr. 8, 1975
Abstract:
A battery-powered hand-held calculator for performing arithmetic,
trigonometric, and logarithmic functions and displaying the results thereof is
provided with the capability of automatically storing the last displayed number
in an auxiliary storage register whenever the next succeeding function to be
performed would destroy that number. That number mey be recalled from the
auxiliary storage register by simply depressing a prefix key and a Last-X
function key.
8 Claims, 2 Drawing Figures
An image of first page of this patent is
available (approximately 47 Kbytes).
It is a TIFF class F file at 300 DPI resolution using ITU-T Group 4 Facsimile
(T.6) coding.
Eric's notes:
This patent covers the Last X function. First implemented in the HP-45, the
Last X function has appeared on almost all subsequent HP RPN calculators.
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Last updated July 17, 1995
Copyright 1995 Eric Smith
eric@brouhaha.com
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