From Maciej Bartosiak:
nonpareil for OS X is a vintage HP calculator simulator. Version provided for OS X is based on nonpareil for Linux - a micro-assembler and simulator package written originally for Linux by Eric Smith.
nonpareil is made available under the terms of the Free Software Foundation's General Public License, Version 2. nonpareil for OS X currently can simulate following calculators: classic (hp-35, hp-45, hp-55, hp-80), woodstock (hp-21, hp-25), woodstock-spice (hp-32e, hp-33c, hp-34c, hp-37e, hp-38c, hp-38e), nut-voyager (hp 11c, hp 12c, hp 15c, hp 16c).
What's new in this version:
Added support for use comma as decimal separator.