WRPN Calculator
| Company type | Open-source software |
|---|---|
| Industry | Software, Scientific calculators |
| Founded | April 3, 1995 |
| Founder | Emmet P. Gray |
Area served | Worldwide |
| Products | Scientific calculator software (HP-16C emulator) |
WRPN (Windows Reverse Polish Notation) is an open-source scientific calculator software designed to imitate the Hewlett-Packard Voyager series' HP-16C "Computer Scientist" programmable calculator.
History
Emmet P. Gray, an American software developer and former civilian employee of the US Army (currently an adjunct professor at Texas A&M University), launched WRPN version 1.0 on April 3, 1995. This 16-bit program, created using Borland C++ 4.0, was distributed as public domain software compatible with early Microsoft Windows platforms.
As of September 2024, WRPN continues to be actively maintained. The most recent release, version 7.1.1, dated August 26, 2024, supports contemporary operating systems via the Java Runtime Environment and is also accessible as an Android application. Its source code is available in multiple programming languages including C#, VB.NET, ASP.NET, and Java.
Features
WRPN closely mimics almost all functionalities of the HP-16C, featuring:
- RPN (Reverse Polish notation) input method
- Modes for Floating point, Decimal, Hexadecimal, Octal, and Binary calculations
- Configurable word lengths ranging from 1 to 64 bits
- Support for signed number arithmetic
- Implementation of Logical operators and Bitwise operators
- A total of 32 storage registers
- A four-level stack
- Program memory accommodating up to 203 instructions
JRPN
In 2019, Bill Foote—formerly the lead engineer at Sun Microsystems responsible for Blu-ray and TV platform standards—created JRPN (JOVIAL Reverse Polish Notation Calculators), an open-source Java-based HP-16C emulator derived from WRPN version 6.0.2. Unlike WRPN’s bitmap font usage, JRPN employs scalable vector fonts and is distributed under the Apache License.
During the COVID-19 pandemic, Foote redeveloped JRPN using Flutter and reissued it under the GPLv3 license. This application provides two versions—15C and 16C—that replicate the HP-15C and HP-16C calculators respectively. It is available across multiple platforms including Android, Linux, Mac OS, Windows, and as a web app.
Separately, an unrelated freeware RPN calculator named JRPN was created by William Giel with its last update in 1999.