WRPN Calculator

WRPN is an open-source scientific software calculator, simulating the Hewlett-Packard Voyager series' HP-16C "Computer Scientist" programmable calculator.

History

On April 3, 1995, Emmet P. Gray, an American programmer, at the time civilian employee at the US Army, now adjunct professor at the Texas A&M University, released WRPN 1.0, a public domain open-source software written in Borland C++ 4.0 for early versions of Microsoft Windows.
As of September 2024 the project is still in active development, and the latest WRPN 7.1.1 was released on August 26, 2024, for modern operating systems with Java installed, and as a mobile application for Android. Source code is available in C#, VB.NET, ASP.NET and Java.

Features

WRPN simulates almost all of the functions of HP-16C:

RPN input support
Floating point, Decimal, Hexadecimal, Octal and Binary modes
Word sizes from 1–64 bits per word
Signed math
Logical operators
Bitwise operators
32 storage registers
4 position stack
203 lines of program memory
JRPN

In 2019 Bill Foote, an American software engineer and ex-Lead of the Sun Microsystems' standardization of interactive technologies for Blu-ray and other TV platforms, created the JRPN, an open-source HP-16C simulator, forked from WRPN 6.0.2 in Java, but with all of the text set to be rendered from vector fonts, and licensed it under the free Apache License.
During the COVID-19 pandemic Foote fully rewrote JRPN code in Flutter and licensed it under GPLv3. JRPN is available now in two variants, 15C and 16C, for Android, Linux, Mac OS, Windows and as a web application.
Also there is another RPN calculator of the same name, developed by William Giel as freeware proprietary software. It has been last released in 1999.