Librcx and associated programs (May 27 1999 release)
Written by Kekoa Proudfoot
Released February 9, 1999
Last original update:  Dec 16 2000

NOTE: Several float lib files were later tweaked in brickOS, including:
* addsf3.s
* divsf3.s
* expandsf.s
* fixsfsi.s
* floatisf.s
* joinsf.s
* normalsf.s


INTRODUCTION

Librcx is intended to be a lowest-level driver for the Lego RCX.  It
provides an interface between your C code and the ROM.  The intent is to
allow you to explore and write programs using the ROM interface, and to
provide a framework in which to start writing code that interacts with the
RCX at even lower levels.  It is therefore possible to use this code as a
starting point for writing something sophisticated, perhaps along the lines
of BrickOS (http://brickos.sf.net/).

Librcx is slowly evolving into a more generally useful library for writing
C code to drive the RCX.  As a first step toward this goal, floating point
support was added in the third release of this code.

Librcx is distributed under the Mozilla Public License.  Please see the
file ./LICENSE for details.

You can find Librcx at:

http://www.mralligator.com/rcx/tools.html#Librcx

COMPILING

I assume you have the GNU H8 cross development environment installed
somewhere, plus the GNU make utility, and maybe a few other tools.

Edit ./Config before compiling.

Type make, and everything should compile.

WRITING CODE

The code in ./progs shows some examples of how to use the routines I
provide; for the most part, you will want to interface with the RCX using
the routines defined and described in ./lib/rom.h.  These routines are
documented to some degree at: http://www.mralligator.com/rcx/#Rom.
Bug me enough and maybe I will finish up the ROM spec, which I have put
aside for the time being.

DOWNLOADING CODE

To download a .srec file to the RCX, compile ./tools/firmdl.c.  See the
comments at the top of that file for compilation and usage details.

NOTES

This program is not sponsored, authorized, or even endorsed by the LEGO
Group.  Do not associate this code with the LEGO Group, there is no such
association.

Librcx does not support C++, but it wouldn't be hard to modify
./lib/rcx.lds to put .ctors and .dtors somewhere and modify ./lib/init.c to
call them at startup/shutdown.  I think you'll also need a lib that
implements the C++ specific routines; I believe this lib is included with
the GCC distribution.

If you find problems with Librcx, of course I'd like to know about them;
however, I may or may not have the time to address any issues brought to my 
attention.  My apologies in advance.

VERSION HISTORY

Feb 9 1999

- initial release

Feb 22 1999

- changed rom.h documentation on read_sensor
- added defines for sensor modes and types
- added test4.c as a short demonstration of how to write sensor code

May 27 1999

- more rom.h header updates
- fixed bug in malloc (user got header address, not data address)
- added floating point support

Dec 16 2000

- updated floating point routines
- added firmdl3 to tools directory