About Free42

Free42 is a complete re-implementation of the HP-42S scientific programmable
RPN calculator, which was made from 1988 until 1995 by Hewlett-Packard.
Free42 is a complete rewrite and contains no HP code whatsoever.
At this time, the author supports versions that run on Android, iOS, Microsoft
Windows, MacOS (application and Dashboard widget), and Linux.


Installing Free42:

Copy Free42Decimal.exe (or Free42Binary.exe, or both) to wherever you want it,
e.g. create a directory "C:\Program Files\Free42" and put it there.
When Free42 runs, it will create three additional files; they are state.bin,
print.bin, and keymap.txt, and they are used to store the calculator's internal
state, the contents of the print-out window, and the PC keyboard map,
respectively.
By default, these additional files will be stored in %APPDATA%\Free42, which is
typically C:\Users\<YourUserName>\AppData\Roaming\Free42.
If you want to run Free42 from a removable drive, like a USB stick, and keep
the state.bin, print.bin, and keymap.txt file with Free42 on that drive, create
a file named "portable" in the same directory as Free42Decimal.exe or
Free42Binary.exe. When Free42 sees this file, it will ignore %APPDATA%\Free42
and keep those files in its own directory.

Free42 comes with two skins built in, but you may use different ones, by
storing them in the directory where Free42Decimal.exe or Free42Binary are
located, or (if not running from a removable drive with the "portable" file),
in %APPDATA%\Free42.

If, when you try to run Free42, Windows says "This application has failed to
start because the application configuration was incorrect. Reinstalling the
application may fix this problem," then you also need to download and install
the Microsoft Visual C++ 2008 Redistributable Package. 
You can download this package from
http://www.microsoft.com/en-us/download/details.aspx?id=29


Uninstalling Free42:

Remove Free42Decimal.exe, Free42Binary.exe, and %APPDATA%\Free42 and its
contents.


Documentation

The ultimate documentation for Free42 is the manual for the HP-42S. You can
obtain this manual in PDF format by purchasing the CD or DVD set from The
Museum of HP Calculators (http://hpmuseum.org/). Alternatively, there is an
independently written HP-42S/Free42 manual, by Jose Lauro Strapasson, which
you can download free at http://joselauro.com/42s.pdf.


Keyboard Mapping

You don't have to use the mouse to press the keys of the emulated calculator
keyboard; all keys can be operated using the PC's keyboard as well. The
standard keyboard mapping is as follows:

Sigma+:   F1, or 'a' as in "Accumulate"
Sigma-:   Shift F1, or 'A' (Shift a)
1/X:      F2, or 'v' as in "inVerse"
Y^X:      Shift F2, or 'V' (Shift v)
SQRT:     F3, or 'q' as in "sQuare root"
X^2:      Shift F3, or 'Q' (Shift q)
LOG:      F4, or 'o' as in "lOg, not ln"
10^X:     Shift F4, or 'O' (Shift o)
LN:       F5, or 'l' as in "Ln, not log"
E^X:      Shift F5, or 'L" (Shift l)
XEQ:      F6, or 'x' as in "Xeq"
GTO:      Shift F6, or 'X' (Shift x), or 'g' as in "Gto"

STO:      'm' as in "Memory"
COMPLEX:  'M' (Shift m)
RCL:      'r' as in "Rcl"
%:        'R' (Shift r)
Rdown:    'd' as in "Down"
pi:       'D' (Shift d), or 'p' as in "Pi"
SIN:      's' as in "Sin"
ASIN:     'S' (Shift s)
COS:      'c' as in "Cos"
ACOS:     'C' (Shift c)
TAN:      't' as in "Tan"
ATAN:     'T' (Shift t)

ENTER:    Enter or Return
ALPHA:    Shift Enter or Shift Return
X<>Y:     'w' as in "sWap"
LASTX:    'W' (Shift w)
+/-:      'n' as in "Negative"
MODES:    'N' (Shift n)
E:        'e' as in "Exponent" (duh...)
DISP:     'E' (Shift e)
<-:       Backspace
CLEAR:    Shift Backspace

<Up>:     CursorUp
BST:      Shift CursorUp
7:        '7'
SOLVER:   '&' (Shift 7)
8:        '8'
Integral: Alt 8 (can't use Shift 8 because that's 'x' (multiply))
9:        '9'
MATRIX:   '(' (Shift 9)
divide:   '/'
STAT:     '?' (Shift /)

<Down>:   CursorDown
SST:      Shift CursorDown
4:        '4'
BASE:     '$' (Shift 4)
5:        '5'
CONVERT:  '%' (Shift 5)
6:        '6'
FLAGS:    '^' (Shift 6)
multiply: '*'
PROB:     Ctrl 8 (can't use Shift * because '*' is shifted itself (Shift 8))

Shift:    Shift
1:        '1'
ASSIGN:   '!' (Shift 1)
2:        '2'
CUSTOM:   '@' (Shift 2)
3:        '3'
PGM.FCN:  '#' (Shift 3)
subtract: '-'
PRINT:    '_' (Shift -)

EXIT:     Escape
OFF:      Shift Escape
0:        '0'
TOP.FCN:  ')' (Shift 0)
.:        . or ,
SHOW:     '<' or '>' (Shift . or Shift ,)
R/S:      '\' (ummm... because it's close to Enter (or Return))
PRGM:     '|' (Shift \)
add:      '+'
CATALOG:  '=' (Can't use Shift + because + is shifted itself (shift =))

In A..F mode (meaning the "A..F" submenu of the BASE menu), the PC keyboard
keys A through F are mapped to the top row of the calculator's keyboard (Sigma+
through XEQ); these mappings override any other mappings that may be defined
for A through F.

In ALPHA mode, all PC keyboard keys that normally generate printable ASCII
characters, enter those characters into the ALPHA register (or to the command
argument, if a command with an alphanumeric argument is being entered). These
mappings override any other mappings that may be defined for those keys.


What's the deal with the "Decimal" and "Binary"?

Starting with release 1.4, Free42 comes in decimal and binary versions. The two
look and behave identically; the only difference is the way they represent
numbers internally.
Free42 Decimal uses the Intel Decimal Floating-Point Math Library;
it uses IEEE-754-2008 quadruple precision decimal floating point, which
consumes 16 bytes per number, and gives 34 decimal digits of precision, with
exponents ranging from -6143 to +6144.
Free42 Binary uses the PC's FPU; it represents numbers as IEEE-754
compatible double precision binary floating point, which consumes 8 bytes per
number, and gives an effective precision of nearly 16 decimal digits, with
exponents ranging from -308 to +308.
The binary version has the advantage of being much faster than the decimal
version; also, it uses less memory. However, numbers such as 0.1 (one-tenth)
cannot be represented exactly in binary, since they are repeating fractions
then. This inexactness can cause some HP-42S programs to fail.
If you understand the issues surrounding binary floating point, and you do not
rely on legacy software that may depend on the exactness of decimal fractions,
you may use Free42 Binary and enjoy its speed advantage. If, on the other hand,
you need full HP-42S compatibility, you should use Free42 Decimal.
If you don't fully understand the above, it is best to play safe and use
Free42 Decimal.


Free42 is (C) 2004-2019, by Thomas Okken
Contact the author at thomasokken@gmail.com
Look for updates, and versions for other operating systems, at
https://thomasokken.com/free42/
