Simple calculator for CP/M
==========================

scalc is a simple programmer's calculator for CP/M (Z80). It's designed to fit
into 16 disk blocks (about 2kB) and use no more memory than that.  It uses
16-bit integer arithmetic, which behaves the same way (including overflows) as
native Z80 16-bit arithmetic does.  

Usage
-----
Although simple, scalc follows proper rules of precedence, and supports
expressions with brackets. scalc calculates expressions directly from the
command line, and displays results in (signed) decimal and hexadecimal.

    A> scalc 2+8
    10  #000A

Alternatively, running scalc without an expression enters interactive mode, in
which expressions can be entered line by line. To leave interactive mode, enter
an empty line, or hit ctrl+c.

Hexadecimal numbers can be entered if preceded with a hash ('#'). As well as
the usual arithmetic operators, scalc supports bitwise logical operations.

The range of numbers is -32,768 to 32,767. The program won't warn you if you
enter a number that is too large to fit into that range, or perform
calculations that overflow the range.

Operators
---------
+, -, *, / have their usual meanings. scalc also supports:

|	bitwise OR
&	bitwise AND
^	bitwise exclusive OR
%	modulus (remainder after division).

The first three of these operators have the same precedence as +/-;
% has the same precedence as division.

Number symbols
--------------
Numbers are decimal unless indicated otherwise. A hexadecimal number is
introduced by a # symbol, e.g., #FF00. To the extent that it is meaningful to
do so, negative hexadecimal numbers can be used, like this: -#AABB. "#-AABB"
won't work. 

The special symbol @ substitutes the result of the last calculation.
Naturally, this only makes sense in interactive mode. This symbol will
otherwise by zero.

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