Historical Document · 1989

US Patent 4,821,228: Method and Apparatus for Computation Stack Recovery in a Calculator (Hewlett-Packard)

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Hewlett-Packard's patent on saving the stack so that an UNDO key can restore it: priority 24 December 1986, granted 11 April 1989.

Author

William C. Wickes, Laurence W. Grodd

Year

1989

Type

Historical Document

Credit

US Patent and Trademark Office; via Google Patents.

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