IC(1)

NAME
ic - integer calculator

SYNOPSIS
ic [expression]

EXAMPLES

DESCRIPTION

Ic is a simple RPN (Reverse Polish Notation) calculator, used for small calculations and base conversions. All calculations are done using 32 bit integers. The standard input is usually a keyboard and the standard output requires a device with a 'termcap' entry. The program starts by interpreting any <args> as commands, where the separation between arguments is considered to be the same as the ENTER key. For example,

"ic 692 784+

After reading the arguments input is from the keyboard.

  Stack Operations

The operation of this program is similar to an RPN calculator. A six level stack is used. The ENTER key pushes the stack up one level. For example, '12+5' is entered as '12 ENTER 5 +".

The top two entries on the stack are exchanged by the x command, and the stack is rolled down one (popped) by the p key. The top of the stack may be cleared by pressing the back-space key. The whole stack and the registers are initialized by a z.

  Numeric Entry

The input and output bases are initially decimal, but they may be changed using the i and o commands. The i command changes both bases, but the o command changes just the output base. These commands take a one character argument of h, d, o or b to change to Hexadecimal, Decimal, Octal or Binary. While the input base is hexadecimal the letters a through f are used to represent the decimal values 10 through 15.

When the input base is decimal: multiply, divide and remainder are signed, otherwise they are performed unsigned.

The output base may also be changed to ASCII (a), this causes the least significant 7 bits of a value to be displayed as a character. To input an ASCII value the translate (t) command may be used, it accepts one character as its argument.

  Calculations

The arithmetic operations supported are: Negate ('.'), Add ('+'), Subtract ('-'), Multiply ('*'), Divide ('/'), and Remainder ('%'). The logical (Boolean) operations available are: NOT ('~'), AND ('&'), OR ('|'), and EXCLUSIVE-OR ('^').

After one of these operations the last top of stack value is saved. It may be restored by pressing l (L).

  Saving Results

Ten temporary registers are available. The Store (s) command followed by a digit ('0'..'9') will copy the top of the stack to the specified register. The Recall (r) command pushes the contents of a register onto the top of the stack.

If the Store command is followed by a '+' preceding the digit, then the top of the stack will be added to the specified 'accumulator' register.

Values may also be written to a file. The w command writes the top of the stack, using the current output base, to a file called 'pad' in the current directory. If the user does not have write access to the current directory then the file /tmp/pad_$USER is used as the scratch pad. The scratch pad file is erased on the first use of the w command within each new invocation of 'ic'.

  Miscellaneous

The Quit (q) key causes an immediate exit. The m command temporarily leaves ic by invoking the shell as a sub-process. For help while using ic, hit the h key. If an erroneous key is pressed the bell will sound.

  Command Summary

Note that many commands have an alternative key-code available on the extended AT keyboard. This aids entry by including most commands on the right side of the keyboard.

	ENTER	Enter (push up)
	BS (DEL)	Clear top of stack
	h	Help
	i	Input base  (h, d, o, b)
	l  (PGDN)	Last top of stack
	m	MINIX shell
	o	Output base (h, d, o, b, a)
	p  (DOWN)	Pop stack (roll down)
	q  (END)	Quit
	r  (LEFT)	Recall (0-9)
	s  (RIGHT)	Store [+] (0-9)
	t	Translate (char)
	w  (PGUP)	Write top of stack to scratch pad
	x  (UP)	Exchange top of stack
	z  (HOME)	Zero all state
	.	Change sign
	+  (+)	Add
	-  (-)	Subtract
	*	Multiply
	/	Divide
	%  (sh/5)	Remainder
	(tilde)	Not
	&	And
	|	Or
	^	Exclusive-or

  Author

Ic was written by Terrence W. Holm.