JRPN 15C/16C - User Guide
This is the user guide for JRPN 15C and JRPN 16C calculator
simulators. The main page is
here, and the privacy policy is
here.
Both simulators try to be a faithful implementation of the behavior
of the original 1980s calculator. For the most part, the user guide
for the original calculators applies. It can readily be found on the
internet. Those guides aren't copied here because I'm unsure of
copyright, and JRPN is a clean-room implementation.
This guide concentrates on some slight extensions, and various settings
that are part of the application. Be aware that the calculation results
in floating point modes can be expected to diverge somewhat from the
original calculator. JRPN maintains floating-point numbers internally
as a binary-coded decimal value with a ten digit mantissa, like the
original. However, for many calculations, the value is converted into
a standard 64 bit double, then the calculation is performed and the result
is converted back. Other operations, like the 15C's integrate and solve
functions, almost certainly use a different algorithm than the
original. Addition, subtraction, multiplication and division are performed
internally in decimal. The trip operations are special-cased at multiples
of 90 degrees/100 gradians, to avoid surprising results. Generally speaking,
Results are believed to be compatible, and in some cases slightly
more accurate.
To illustrate this, consider 9^7.1. With a 12 digit mantissa,
that comes to 5958292.46652. The real HP 15C gives
5958292.466, whereas JRPN gives the slightly more accurate
result of 5958292.467. Neither is wrong - the real calculator
is behaving as advertised, applying the even-odd rule to an 11 digit
internal mantissa, rouding the 5 to an even number in the next digit over.
JRPN's value is a 64 bit IEEE float, which has a more precise 53 bit
binary mantissa that's used when rounding to a 10 digit decimal mantissa.
A 53 bit binary mantissa is equivalent to between 15 and 16 decimal digits.
The ON Button
The original calculators let you access special functions by simultaneously
pressing the ON butten and some other buttons. In the simulator, press the
ON button once to access these functions; pressing it a second time quits
the program. The other "hidden" features are swapping commas and decimal
points ("Euro mode"), a calculator reset, and a calculator self-test.
Settings
Note that some settings are only available on mobile platforms
(Andriod and IOS).
- Show Menu Icon - If unchecked, gets rid of the
Android-style dots that provide a visual cue that a menu
is there. In this mode, you still access the menu by pressing
in the upper-right hand corner of the UI.
- Disable System UI Overlays (mobile) - Hides Android/IOS
system UI elements, so you just see the calculator.
- Orientation (mobile) - Lets you lock the orientation to
portrait or landscape. Personally, I leave this locked to
landscape, since this simulates the real calculator.
- Key Feedback - Lets you force a key feedback different
than the platform default. For example, on Android the default
platform key feedback is a click, but I prefer haptic feedback.
If you want key feedback on Android, make sure you have
"Touch sounds" and/or "Touch vibration" enabled in your device
settings.
See also
Issue 63 and
Issue 102.
This area has been an area of significant churn in the Android
platform. Normal haptic feedback uses the Android haptic API, and
heavy haptic feedback uses the vibration API (well, one of three
APIs, depending on OS level.) It seems that it is not uncommon
for one to work and the other not to, depending on Android device.
¯\_(ツ)_/¯
- Long Numbers - Controls how long numbers are displayed,
like "123456789ABCDEF0 h" or "-1.234567891 27". The default
is to behave like the original calculator. In landscape mode,
the LCD display can be stretched enough to fit a 64 bit hex
number. The digit size can also be shrunk to fit more in.
- Show Accelerators - Shows keyboard accelerators.
- System Settings, ms/Program Instruction - lets you control
how fast programs execute. By default, the calculator delays for
50ms after each instruction, which generally yields performance about
3x the original in my experience.
- System Settings, Total Memory - lets you control the user
memory, which is used for registers, programs, matrices on the 15C,
etc. It does not include memory used for the index register,
the stack, and other fixed memory overheads. Memory can't be set
to less than the original calculator's, and can be set up to
1 Mega-nybble. A nybble is half a byte, that is, four bits.
- System Settings, Color Settings - lets you tweak various
colors in
the UI, by entering a hex RGB value. For example, if you like a
slightly different shade of gold for the F key, you can set it here.
- System Settings, Read/Write Config - lets you set a
screen configuration / layout to
customize the button arrangement.
- System Settings, Debug Log - captures debug information,
including a record of keypresses, in an internal memory buffer.
This information is included if you copy the calculator state
to the clipboard in the File menu, and might be useful for a
bug report. To date, this has never been necessary.
File Menu - Read
- Restore Starting State - Restores the calculator to its
last saved state.
- Read from Clipboard - Reads calculator state from the
clipboard. This can be used to copy it from JRPN on another
device, by sending the string and copying it to the clipboard.
File Menu - Save
- Save as Starting State - saves the current calculator state.
The calculator does this automatically when it's shut down or when
you turn it off using the ON button, so normally this isn't needed.
- Copy to Clipboard - Copies the current calculator state to
the clipboard. You can use this to send it to another copy of JRPN
on a different device.
- Export to Application - Like Copy to Clipboard, but sends
the data to another program, e.g. using an Android intent.
- Copy URL to Clipboard - Like the previous two, but encodes
the state as a URL that can be used to launch the web version of
JRPN.
File Menu - Import/Export Program
These menu options let you import and export a human-readable
program listing. It may be possible to use this to send and receive
programs to/from other HP 15C/16C simulators. The format is based
on the documentation from
Torsten's
HP 15C Simulator. I added this feature at Torsten's request.
Reset All
Restores the simulator to its default settings.
Bill Foote