United States Patent 3,987,290
Calculator Apparatus for Displaying Data in Engineering Notation
Oct. 19, 1976
Inventor: Peter D. Dickinson, Monte Sereno, Calif.
Assignee: Hewlett-Packard Company, Palo Alto, Calif.
Filed: May 19, 1975
Appl. No.: 578,775
Abstract:
Digital data in floating-point notation is arithmetically formatted for display
in engineering notation with an exponent that is always a multiple of three and
a mantissa having a decimal point. The formatting is performed under control
of a routine stored in a read-only memory (ROM) of a data processing unit.
8 Claims, 6 Drawing Figures
An image of first page of this patent is
available (approximately 33 Kbytes).
It is a TIFF class F file at 300 DPI resolution using ITU-T Group 4 Facsimile
(T.6) coding.
Eric's notes:
The hardware described in this patent is that of the Classic series, but none
of the released machines in that series actually had engineering notation.
The HP-25 was the first HP calculator to have engineering notation, and unlike
most later HP calculators, if you put it in "ENG n" mode, it displayed n+3
digits of the mantissa.
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Last updated July 17, 1995
Copyright 1995 Eric Smith
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