A great software repository for HP42s is the www.hp42s.com

Mathematics

QPI Approximate decimal numbers by fractions on various forms

Prime Number Factorisation Factorises integers up to 99 999 999

Miller-Rabin Primality Test Primality test for integers up to 999 999 999 999.

Big Factorial Aproximate factorials (N!) for N larger than 253.

Find the root, min and max of a function using Newton's algorithm

Find the roots of two nonlinear equations using Newton's algorithm

Find the roots of several nonlinear equations using Newton's algorithm

Games

Minehunt game Graphical minehunt game for the HP-42S

Okie Dokie Graphical puzzle game converted from the Atari 2600

The Caves Adaptation of a classic HP-41C game

Trek Star Trek game written originally for the HP-42S

Black Jack Black Jack game adatpted from the HP-41C

Programs for Free42s/Hp42s (taken from Thomas Okken website):

plot_orig.raw | Original version of PLOT from the HP-42S manual. Plots a function on an HP-82240 printer. |

plot_thomas.raw | Modified version of PLOT; like the original, with SOLVE support added. |

miscfn.raw | Original version of MISCFN from the HP-42S manual. Calculates (x/360) * sin(3*x) + 1; used to demonstrate the PLOT program. Set DEG and ALL modes; in PLOT, use YMIN=-0.5, YMAX=2, AXIS=0, XMIN=-360, XMAX=360, XINC=45. |

dplot_orig.raw | Original version of DPLOT from the HP-42S manual. |

dplot_thomas.raw | Modified version of DPLOT; like the original, with SOLVE support added. |

wave.raw | Calculates sin(x) * sin(5*x). Used to demonstrate DPLOT. Set DEG mode; in DPLOT, use YMIN=-1, YMAX=1, AXIS=0, XMIN=0, XMAX=180. |

gc.raw | SOLVE program to compute the Great Circle Distance between two points on the Earth. Coordinates should be entered in decimal degrees; distance is computed in kilometers. |

sun.raw | SOLVE program to compute the height of the sun above the horizon. Variables used: TILT: the angle between the Earth's axis of rotation and the normal of the ecliptic (23.5 degrees); LAT: observer's latitude (use positive values for Northern latitudes, negative values for Southern latitudes); SEAS: the current season, given as an angle between 0 and 360 degrees, with 0 being mid-winter in the Northern hemisphere, 90 being the Northern Spring equinox, etc.; TOD: time of day (solar time, from 0-24, where 12 is noon; solar time differs from official time, depending on where you are within your time zone); HGHT: height of the sun above the horizon, in degrees; negative numbers mean nighttime. |

prm_dec.raw | Original version of Erik Ehrling's PRM? program. NOTE: this program relies on decimal math, and will NOT produce correct results on Free42 Binary. |

prm_bin.raw | Modified version of PRM?; works with binary math, enabling it to run on Free42 Binary. Before using, store 2^20 in "E6" and 2^40 in "E12" (you can use 2^26 and 2^52, respectively, too; that way the program can work with even larger numbers). |

diag.raw | Constructs band-diagonal matrices. Put the desired dimension in X, and put a vector containing the (off-)diagonal elements in Y. If the vector's length is odd, its middle element will go on the diagonal; if its length is even, the element just before the middle will go on the diagonal. |

stress.raw | Not actually a functional program; just contains all the HP-42S instructions with all legal types of arguments. I used this to test the "raw" mode program import/export in Free42. |

mast.raw | The classic Master Mind number-guessing game. Numbers can contain digits 1 to 6, with duplicates allowed. Results are displayed as B.W, with B the number of black pegs (right color AND right position), and W the number of white pegs (right color, wrong position). Use the "up" and "down" keys to scroll through the current game's history. |

minehunt.raw | Minehunt game, similar to the built-in game on the HP-48. By Erik Ehrling. |

rtmin.raw | A program that finds extrema and roots of arbitrary functions. Contributed by Namir Shammas; see here for documentation. |

RootsEqns.raw | A program that solves multiple nonlinear equations. Contributed by Namir Shammas; see here for documentation. |

mlran.raw | A program that performs multiple linear regression. Contributed by Namir Shammas; see here for documentation. |

pi_dec.raw | Calculates up to 1110 Digits of pi on the HP-41, more on a 42S. Put the desired number of digits in X and do XEQ "PI". When done, the digits of pi will be stored in register 04 and up. See here for documentation and the program listing. NOTE: this program relies on decimal math, and will NOT produce correct results on Free42 Binary. |

NikkelTaylorCadastral.zip | Cadastral Program, contributed by Tony Nikkel. (Blurb, Flyer, Installation Instructions. Note: these materials are also included in the download package.) |

aes.raw, aesprep.raw | Advanced Encryption Standard, contributed by Brett Stevens. Program listing and documentation is here; the author's web page is here. Note: the aesprep.raw file contains a program that initializes registers 00-63 and 90-153 as described in the documentation; the aes.raw file contains the AES code itself. |

Base.raw | ASCII, Hex, Decimal, and Binary conversions. See here for documentation. Contributed by Ton van de Burgt. |

Convert.raw | Unit conversions. See here for documentation. Contributed by Ton van de Burgt. |

Finance.raw | A collection of financial programs. See here for documentation. Contributed by Ton van de Burgt. |

Triangle.raw | Calculate the sides and angles of a triangle. See here for documentation. Contributed by Ton van de Burgt. |

ses.raw, sestest.raw | Simultaneous Equation Solver, based on an RPL program by Mike Ingle. See here for documentation. |

RealEigenvalues.raw | Calculate real eigenvalues of a real-valued square matrix. Contributed by Pierre Gillet; see here for documentation. |

G4_G3_G2.raw | Solves 2nd, 3rd, and 4th order polynomials. using closed-form solutions. Contributed by Christian Vetterli. |

STATISTICS.raw | Statistics package, with four regression models, mean, standard deviation, median, extremes, chi-square and Student-t distributions, and more. There is some documentationhere. Contributed by William Solano. |

days.raw | Calculate the number of days between dates. Contributed by Russ Jones. |

ntrp.raw | Perform linear interpolation. Contributed by Russ Jones. |

lrnc.raw | Perform learning curve calculations. Contributed by Russ Jones. |

mort.raw | Perform mive value of money (annuity) calculations. Contributed by Russ Jones. |

FWIW-1.0.zip | SHOW replacement that displays the contents of X in Free42's full 25 digits of precision. Includes an annotated listing. Contributed by Glen Sanft. |

delsnider.zip | A collection of civil, road, and municipal programs. Contributed by Ken Delsnider. |

Other interesting HP42s related links:

**HP-42S - Wikipedia, the free encyclopedia** 64 KB of ROM; Functions: Over 600; Expandability: Officially no other than IR printing (32K ... * in all samples the line numbers are part of HP-42S code editor, and programmer does not ...**HP Looks into Plans to Publish the HP-42S ROM Online** HP Looks into Plans to Publish the HP-42S ROM Online Friday 12th of March 2004 In response to a request to publish the HP-42S ROMs online at www.hp42s.com - Gene Vicino (Marketing ...**HP-42S: New Facts** HP-42S: New Facts. Posted by J-F Garnier (France) on 10 Apr 2002, 4:32 p.m. Contents: Introduction 1. ROM dump 2. Hardware 2.1 Display 2.2 Announciators**HP-42S** The serial interface came only later with the much larger HP-48. According to Nelson M. Sicuro the ROM version of the HP-42S can be determined as follows:**HP-42S Features** Features in optional ROMs are listed as Option. Features in HP mag card or tape Application Pacs are listed as +. Other software is not included.**Free42, an HP-42S calculator simulator** It is a complete rewrite, and doesn't use any HP code. You do not need an HP-42S ROM image in order to use it, yet it is fully HP-42S compatible.**An Alternative HP-42S/Free42 Manual** And it also would be nice to have HP-42S ROM images for free just like what happened to HP-48G and other models and keeping PDF versions of the manuals of retired models to download ...**HP Calculator Emulators for the PC** Emulators for Hewlett Packard ... simulator of the HP 42S scientific programmable RPN calculator. Because this is a written-from-scratch simulator, it does not need a ROM from ...**Christoph Giesselink Emu42 Page** Includes KML scripts for the HP-17B, HP-17BII, HP-27S, HP-28S and HP-42S and the source code of the emulator, but no ROM images.**Keep the HP spirit alive!** HP will never include Emu42 and the HP-42S ROM in the factory setup of their Pocket PC:s (why not include the HP-17BII and the HP-27S ROM at the same time and no-one would ever ask ... **HP-42S Links** Thomas Okken's implementation of the HP-42S for a wide range of computers and operating systems. This software does not require any HP ROM images and was written from scratch by ... **Free42 - HP-42S Emulator** Free42 (v.1.4) is an open source and skinnable emulator for the HP-42S calculator. Although, there are other emulators like Emu42, this one does not require the original ROM image ... **Christoph Giesselink Emu48 10 Years Anniversary Page** He and Jean-Francois Garnier worked on disassembling the HP-42S ROM. The only thing we know at this time was that the HP-42S is using a chip called Lewis, having a Saturn ... **HP-42X MicroCode Emulator: Installation Guide** Receive the HP42X file from the computer and store the (unnamed) backup object containing the HP-42S/Emulator ROM (from the HP42X variable) to Port2 with 2 STO (or Port1 with 1 STO **Hewlett-Packard HP-42S | A collection of programmable and non ...** ROM: Functions + - × ÷ Display: Type: LCD: Size: 131×16 pixels: Dimensions: L×W ... http://cgi.ebay.com.au/HP-Hewlett-Packard-Scientific-Calculator-RPN-42S ...