README FILE FOR THE MIXAL DISTRIBUTION

This is an assembler and interpreter for Donald Knuth's mythical MIX computer,
defined in:

Donald Knuth, _The Art of Computer Programming, Vol. 1: Fundamental 
  Algorithms_.  Addison-Wesley, 1973 (2nd ed.)

This is *not* the GNU MIX Development Kit.  You can find that at:

	http://gnu.essentkabel.com/software/mdk/mdk.html

This implementation was designed and written by Darius Bacon
<djello@well.sf.ca.us>, then ported to UNIX and debugged by Eric S. Raymond
<esr@snark.thyrsus.com>.  Corrections to multiplication and division by
Larry Gately <lgately@rohan.btg.com>; see Notes.

		AUTHOR'S IMPLEMENTATION NOTES

There is one significant difference in the assembler format: Knuth puts
fields at fixed offsets on a line, while I separate them by whitespace.
(Purists may wish to fix this obvious bug.)

The tape devices are currently unimplemented.  (Use the 'card punch'
and 'printer' devices if you don't need mass storage.  They're
automatically connected to standard input and output.

Floating-point instructions aren't implemented either.  They weren't
covered in Volume I, which is all I've got so far.

This MIX is a binary machine.  I think that was a mistake -- decimal
would make debugging enough nicer to compensate for the decreased
efficiency.  When dumping internal values, it prints them in octal, so
you can get the field values by inspection.

Things to do are marked by a comment starting with **. 
The program still needs more testing.

			PORTING AND TESTING

The code is written in pure ANSI C.  It is known to work in the
following environments:

	OS		Compiler
	-----------	------------
	BSD/386		gcc
	AIX-3.2.5	gcc
	DOS		Watcom C
	DOS		Borland C

You can regression-test the interpreter with mixtest (under UNIX) or
test.bat (under DOS).

			FILES

asm.[ch]	A Silly Module
cell.[ch]	Operations on MIX words (Cells)
charset.[ch]	The character set
driver.[ch]	Assemble a single source line
elevator.mix	Sample code from Knuth vol. 1
io.[ch] 	Simulate MIX I/O devices
main.c		Main program
Makefile	Makefile for Unix
makefile.dos	Makefile for Borland C++ under MS-DOS
MIX.DOC  	Excerpt from The Art Of Computer Programming describing MIX.
mix.h		Header for things needed all over the program
mixtest 	Regression-testing shell script
mystery.mix	Sample program
mystery.out	Its output
NOTES		Notes on the MIX assembly language
op2c.awk	Converts the table of instructions into a C array
opcodes 	The table of instructions
ops.inc		The same, as a C array, for the awkless
parse.[ch]	Parse an operand field
prime.mix	Sample program, with notes on MIX assembly language
prime.out	Its output
README  	General info
run.[ch]	Simulate the MIX machine
symbol.[ch]	The symbol table
test.bat	Regression-testing DOS batch file