kcalc -- a scientific calculator for CP/M
=========================================

kcalc is a scientific calculator utility for the CP/M 2.2 platform. It can
evaluate expressions from the command line, but it also has  an interactive
mode with rudimentary, WordStar-like line editing.

The floating point math library the program uses provides about 11-12
signigicant figures of precision, and results are displayed to nine figures.

kcalc follows proper arithmetic rules of precence; brackets can be used
to group terms in the conventional way.

A number of logarithmic and trig functions are provided -- type "list" at the
prompt to see them all.


Example
-------

    A> kcalc sin (pi/4)
    0.70710678     

Results are displayed in decimal or hexadecimal: use "dec" or "hex" at the
prompt to select which is used.

Numbers
-------

Numbers are assumed to be decimal, unless they are preceded by '#' to denote
a hexadecimal number.  Decimal numbers can be entered in scientific notation
(e.g., `1.2E10`).  To enter a negative hex number, put the minus sign first:
`-#20`. Hexadecimal numbers can't be fractional, or use scientific notation. 

Operators
---------

The usual math operators are supported; to calculate a power use `^`, e.g.,
`2^16`. The modulus (remainder) operator is `%`, e.g., `7%3`.

Enter `help` at the prompt for more information.

Interactive mode
----------------

kcalc enters interactive mode if invoked without an expression on the command
line.  It supports basic line editing, with WordStar-like key bindings.  To
get a list of key assignments, type "keys" at the prompt. 

To leave interactive mode, enter "quit", or just hit ctrl+C.

Use the `sigfig` command with a single digit (`sigfig 8`) to set the
precision of the output. Although the Aztec floating point library provides
about fourteen digits of precision, `KCalc-CPM` currently only 
displays one to nine digits, with five being the default.

Variables
---------

You can define up to ten new variables like this:

    kcalc> twopi = 2 * pi

Variables can freely be used in later expressions. 


Notes
-----

All function and variable names are case-insensitive.

All angles are in radians by default; to use degrees type "deg" at the
prompt. 

"ans" is a built-in variable that denotes the last result calculated.

The "log" function is the _natural_ (base-e) logarithm -- use "log10" for
common (base-10) logarith. The "exp" function is the base-e antilogarithm,
that is, e to the power x. There is no common antilogarithm function -- just
do "10^x".

The maximum line length in the editor is 127 characters

There is, at present, no way to define new functions, or to read definitions
from a file, or to log results to a file.

kcalc can only display hexadecimal numbers up to #FFFFFFFF.  Attempting to
display a number larger than this in HEX mode will lead to odd, completely
bogus, results.

Author
------
kcalc is maintained by Kevin Boone, and is distributed under the terms of the
GNU public licence, v3.0.