Nonpareil – microcode-level simulator for electronic calculators

Nonpareil is an open source microcode-level simulator for electronic calculators. The software simulates some of the HP calculators introduced between 1972 and 1982.

Simulation fidelity is achieved through the use of the actual microcode of the calculators. Consequently, the simulation behaviour exactly matches that of the real calculator. In particular, numerical results will be identical, because the simulator is using the BCD arithmetic algorithms from the calculator.

Nonpareil attempts to run the simulation at the same nominal rate of microinstruction execution as a real calculator, e.g., 3500 microinstructions per second for an HP-55.

Nonpareil requires the GTK+ toolkit.

Features include:

  • Simulates the following calculators:
    • HP-35, HP-45, HP-55, HP-80;
    • HP-21, HP-25;
    • HP-31E, HP-33C, HP-34C, HP-37E, HP-38E, HP-38C;
    • HP-41CV, HP-41CX.
  • Simulates an 82143A printer.

Support: Microcode-Level Calculator Simulation
Developer: Eric Smith
License: GNU GPL v2


Nonpareil is written in C. Learn C with our recommended free books and free tutorials.

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