This is the original readme file from the MS-DOS program in 1999
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BigCalc Extended Precision Calculator

BIGCALC works like an H-P calculator with stack and ten memory registers.
Maximum precision settable from 3 to 1075 digits. Exponents to 999999999.
Execute BIGCALC like this:

  BIGCALC precision   (precision is maximum number of digits, default is 50)

BIGCALC has +, -, x, , vX, X, X!, Y^X, logs, trig, pi, e, print, much more.
All trig functions work in radians. BIGCALC is fast, but some operations on
large numbers may take up to several minutes. You can abort long calculations
by pressing the Escape key. Press F1 for on-screen help. Registers can be
viewed in full, or printed to printer or disk.

You can specify floating decimal or scientific notation display. Large numbers
display in scientific notation to about 65 digits all the time, but the view
and print commands show full precision in 3 or 5 digit groups.

Data entry:
To enter a number just begin typing it in. Use Backspace to back up.
To enter an exponent press E then enter the exponent.
Press S while entering mantissa or exponent to change respective sign.
If you start a number with E a mantissa of 1 is assumed.

View displays any register to full precision.
Clear, Print, View, Store, Recall & eXchange ask for affected register.
BackSpace backs up while entering number.

This program emulates a Hewlett-Packard calculator with four register stack
and ten memory registers.  The stack consists of the X, Y, Z & T registers.
The memory registers are 0-9.

The X register is 'where the action is'.  When you enter a number it is entered
into the X register.  If X already contains a number, that number is 'pushed'
up to Y, Y is pushed to Z, Z to T, and the contents of T is lost.  The 'Enter'
key pushes the stack and duplicates X into Y. A number entered into X after
Enter or ClearX DOES NOT push the stack. When you use a function that acts on
two numbers (like + or -) it always acts on X & Y (except for Store, Recall &
eXchange which act on X and a memory register).  The result is put in X, and
the stack is 'Dropped'.  That is, Z copies to Y and T duplicates into Z.

Numbers are displayed in 'Floating Decimal' or 'Scientific Notation' format.
Floating Decimal looks like this:    1.2     123.45     -12300000000  0.000002
Scientific Notation looks like this: 1.2 e0  1.2345 e2  -1.23 e10     2.0 e-6
Very long numbers take longer to compute, of course. You can abort a long
calculation by pressing the Escape key.

If a number is too large or small for the screen, Scientific Notation is used.
All results are truncated except for Y^X which is rounded: 5 up 4 down.

 Judson D. McClendon           $20 gets you a disk with the complete C source.
 Sun Valley Systems
 4522 Shadow Ridge Pkwy        There is no warranty of any kind.
 Pinson, AL 35126-2192         The author assumes no responsibility for the
     205-680-0460              use of this program.
