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MultiCalc 1.0
A Precision Calculator
for the
Commodore
AMIGA
November 1, 1988
Kenneth Johnson
Introduction
The purpose of this document is to describe the features
of
MultiCalc 1.0
and help the user make the most of them.
This program originated as an exercise in curiosity - both in
terms of the methods used to compute the standard functions
on a scientific calculator and with regard to the features of
the
AMIGA
. I have never seen a high-precision general
purpose calculator on a computer, and I thought it might be a
useful addition to
AMIGA
public domain programs as well as a
good first project for myself.
MultiCalc 1.0
is not blazingly fast. It is optimized
for doing operations with precision from 50 to around 3000
digits. However, dealing with numbers this large is always
slow, and this program is no exception. The slowest opera-
tions are those involving inverse trigonometric functions: I
would not recommend using these functions with precision over
100 unless you have plenty of time to wait. The program can
handle numbers of any size up to 32000 digits. If you need
greater precision than this, I would recommend buying time on
a supercomputer!
In designing the program I opted to use a Reverse Polish
Notation (RPN) stack-based format. Memory is allocated
dynamically, so your stack size is only limited by the amount
of available memory. If you are not familiar with stack
based calculators, the concept is quite simple: all opera-
tions are computed on the numbers at the top of the stack,
and the <Enter> key is used to place numbers on the stack.
There is an indicator at the top of the display that indicat-
ing the current depth of the stack. I have implemented a
circular stack - the number shown in the display is always
the top of the stack. Moving down places the top item at the
bottom of the stack, and moving up places the bottom item at
the top of the stack.
I hope that this program will be useful. It is fairly
compact, requiring only 24K of Chip memory, and I used an
adaptation of Leo Schwab's iconify routine so that it can be
loaded without cluttering the screen when not in use. Still,
it is far from perfect, and suggestions for improvement are
always welcome. Please address any correspondence to:
Kenneth Johnson
3018 Trail's End NW
Albuquerque, NM 87120
Getting Started
MultiCalc 1.0
can be started from either the Workbench
or CLI. The program takes one optional argument, namely the
numeric precision. This can be any number from 20 to 32000;
anything else will result in the default precision of 48 (the
size of the display). A sample call is as follows:
1>
MultiCalc 500
This would bring up the calculator with a precision of 500
digits. Keep in mind that you cannot change the precision
once the program has started, so if you will be dealing with
very large or very small numbers, you should set the preci-
sion accordingly.
When running from the Workbench, it is only necessary to
double-click on the
MultiCalc 1.0
icon. The precision will
default to 48, but it can be set with a Tool Type entry. To
make this entry, select the icon from Workbench and then
selct the Info item from the Workbench menu. You can then
ADD a Tool Type entry as follows:
PRECISION=500
This entry would set the calculator's precision to 500
digits. Finally, you must press the SAVE gadget on the
bottom left corner of the Info window. It is important that
the entry be made in capital letters and without any spaces.
Once this is done, double-clicking on the calculator icon
will bring up
MultiCalc 1.0
with the desired precision.
Entering Numbers and Using the Stack
Almost every feature of
MultiCalc 1.0
can be accessed
either with the mouse or the keyboard. Numbers can be
entered with the mouse by clicking on the number gadgets in
the calculator window, using the left mouse button. Each
click is registered upon releasing the mouse button, so if
you change your mind about a digit, simply move the mouse
away from the gadget before releasing the button. If a
mistake is made in entering a number, the BackSpace gadget
can be used to remove one digit at a time.
Using the keyboard, the digits can be entered using
either the numeric keypad or the regular typewriter numbers.
The space bar is used to change the sign of the number, and
the BACK SPACE key is used to back up one digit at a time.
Keep in mind while backspacing that the decimal point (.)
will "absorb" a back space, even though the display will not
change when this happens.
The <RETURN> and <ENTER> keys are used to add numbers to
the stack. When either is pressed, the number currently in
the display is duplicated and placed on top of the stack, so
that a number can easily be entered many times. However, if
any digit is pressed at this point, the display will be
initialized and a new number will be started. In this case,
BACK SPACE has the same function as the Clear button ('c' on
the keyboard): the display is cleared and initialized to
zero. However, the Change Sign button (space bar on the
keyboard) will not initialize the display - it merely changes
the sign of the current entry.
If the number is larger that the display, the left and
right arrow keys can be used to shift the display to the left
and right, respectively. Also, the SHIFT key can be used in
conjunction with the arrow keys on the keyboard to shift the
display to the left and right ends of the number. The up and
down arrow keys are used to rotate through the contents of
the stack. The Swap button (HELP key on the keyboard)
switches the places of the top two entries of the stack.
If a number key is pressed after using any of the
arithmetic, function, or stack-manipulation keys, a new entry
is added to the stack automatically, and the preivious
contents of the display are preserved as the second item on
the stack. However, the BACK SPACE and Clear buttons retain
their function of merely resetting the contents of current
display entry to zero.
Finally, the Delete button (SHIFT-DEL from the keyboard)
is used to remove an entry from the stack. If there is only
one entry on the stack, this button acts like the Clear
button.
Use of Function Keys
All of the arithmetic and other function keys are
available from both mouse and keyboard. For the keyboard
equivalents, please see the Summary of Keyboard Functions
below. There are some special considerations with regard to
a few of these functions, and these are detailed in this
section.
First, it is important to keep in mind that all binary
operations use the two numbers on the top of the stack. In
some cases, the order of these numbers is important. When
using the division operator, the divisor is taken to be the
number on the top of the stack. In raising a number to a
power, the power is the number on top. Finally, Rectal
coordinates are stored with the y coordinate on top, while
Polar coordinates are stored with the angle on top.
There are three buttons that define how the calculator
will deal with the trigonometric functions. Unlike other
buttons on the calculator, these three register a change as
soon as the mouse button is pressed, instead of when it is
released. First, the Radians/Grads/Degrees button is used to
define the unit of angle measurement. This affects the
trigonometric functions (except when in Hyperbolic mode) as
well as the Polar to Rectal and Rectal to Polar conversions.
The default mode is Radians, so be aware of this if you need
to use something else.
The Trigonometric/Hyperbolic and Normal/Inverse buttons
only affect the outcome of the Trigonometric functions. The
default is Normal-Trigonometric, and the calculator is always
returned to this state after a Trigonometric operation.
Finally, the Fix button is used to restrict the display
to a specified number of digits after the decimal point. It
is important to keep in mind that this does not truncate the
number in any way - only the display of the number is affect-
ed. To use this feature, simply enter the number of digits
desired and press the Fix button. The display will then be
cleared and ready to accept input for another number. Any
fractional portion is ignored when using this function, and
the number zero is used to signify a full display. When
entering numbers in this mode, it is possible to continue
entering digits past the cutoff. These will not be seen, but
can nevertheless be edited in the standard way.
The Menu
The menu provides several additional non-numeric func-
tions to the calculator. The 'About...' item does nothing
especially useful, but gives some information about the
product. The 'Delimited' flag pertains to the 'Save Stack'
item and will be discussed with it below.
The 'Iconify' item causes the calculator window to
disappear and a small icon to take its place. My thanks to
Leo Schwab for providing the inspiration for and the basic
form of the routine that takes care of this function. This
icon can then be moved around the display, and out of the way
of other activities. In order to reopen the calculator
window, simply double-click on the icon.
The 'Load Stack' item will fill the stack with numbers
that are stored in ASCII form in a file. Most commonly this
will be used to restore numbers saved using the 'Save Stack'
item, but it can also be used in conjunction with any text
editor to load any numbers of your choice into the calcula-
tor. Invoking this option will bring up a requester for the
name of the file from which to load the numbers. Simply
click on the box to enter the name of the file, and click on
the 'Accept' gadget to initiate the load.
The 'Save Stack' item takes the contents of the stack
and saves them in a file. The procedure is similar to that
involved in 'Load Stack' above. However, the 'Delimited'
item in the menu can be selected or deselected to indicate
whether you want your output to be delimited by commas and
spaces. Also, if the file already exists, the current stack
will be appended to the end of its contents, otherwise a new
file will be created.
The 'Quit' option does just what its name implies - it
terminates the program. Keep in mind that several of the
menu items can be invoked with their keyboard equivalents
using the Right-Amiga key.
Summary of Keyboard Functions
* Multiplication
/ Division
+ Addition
- Subtraction
SPACE Change Sign
c Clear Display
BACK SPACE Delete a Digit
SHIFT-DEL Delete a Number from the Stack
RETURN Add a Number to the Stack
ENTER Add a Number to the Stack
HELP Swap the Top Two Stack Entries
Up Arrow Rotate the Stack Up
Down Arrow Rotate the Stack Down
Left Arrow Shift the Display to the Left
Right Arrow Shift the Display to the Right
SHIFT-Left Arrow Shift the Display to the Left End
SHIFT-Right Arrow Shift the Display to the Right End
ESC Rotate Radians/Grads/Degrees
F5 Rotate Trigonometric/Hyperbolic
F10 Rotate Normal/Inverse
F1 Log Base 10
F2 Log Base e
F3 10 Raised to a Power
F4 e Raised to a Power
F6 Sin/Sinh/ArcSin/ArcSinh
F7 Cos/Cosh/ArcCos/ArcCosh
F8 Tan/Tanh/ArcTan/ArcTanh
F9 Pi
SHIFT-F1 Reciprocal
SHIFT-F2 Square a Number
SHIFT-F3 Raise a Number to a Power
SHIFT-F4 Raise a Number to a Reciprocal Power
SHIFT-F6 Change Rectal to Polar
SHIFT-F7 Change Polar to Rectal
SHIFT-F8 Fix the Number of Decimal Digits
SHIFT-F9 Factorial
Amiga-I Iconify
Amiga-L Load the Stack from a File
Amiga-S Save the Stack to a File
Amiga-Q Exit the Program
Copyright Notice
MultiCalc
is copyright 1988 by Kenneth Johnson. The
binary code may be distributed free of charge in any form as
long as this document is included with it. Special permis-
sion must be obtained to distribute
MultiCalc
for a fee, and
this permission is extended to all not-for-profit User's
Groups to defray copy and distribution costs, as well as to
those distributing collections of
AMIGA
public domain soft-
ware.
If you find that
MultiCalc 1.0
is particularly useful,
or if you have any questions, comments, or suggestions for
future improvements, or if you would like a copy of the
source code, donations and other correspondence should be
addressed to:
Kenneth Johnson
3018 Trail's End NW
Albuquerque, NM 87120
Enjoy!
c