Free42 Decimal3.3.12

Free42 Decimal runs HP-42S calculator programs on a Mac, letting you reproduce programmable calculator calculations in a desktop simulator. You can load and save programs, preserve multiple calculator states, switch between those states, and copy or paste scalar values during a calculation. Its decimal arithmetic uses a 34-digit mantissa with an exponent range from 10⁻⁶¹⁴³ to 10⁶¹⁴⁴, extending the HP-42S representation of a 12-digit mantissa and 10⁻⁴⁹⁹ to 10⁴⁹⁹.

The simulator adds HP-42S instructions and includes time and date functions, base-conversion enhancements, display options, and string and list operations. It also supports editing lists and provides the HP-42S undocumented MIN, MAX, and FIND functions. These features make it useful for people maintaining HP-42S programs, checking calculator routines, or carrying programmable scientific and engineering calculations on a Mac.

The current MacOS release is version 3.3.12 and supports both Intel and Apple Silicon hardware. It is freeware. After a hard reset, the decimal separator follows the computer’s locale: locales using a decimal comma select RDX, mode, while other locales select RDX. mode, so programs producing formatted output may require the matching setting.