readme

关于SHELL方面的

This directory contains the source code for a simple game called Xinu
worm.  The game started as a lab assignment for CS503, our operating
systems class, and was ported to Sun3 Xinu to use for testing and
debugging.  It is intended as a simple example of some of the
capabilities of Xinu, and not as a full-fledged game.  The game is
process and message passing based.  Part of the assignment was to
write a "wide message" passing scheme, that could send messages of
multiple words to other processes using a simple procedure call style.

The game contains the following communicating processes:

plotter:  Responsible for all screen output
mover:    Responsible for accepting keyboard input and moving the
          player's worm figure.
robot:    A robot is created as an opponent. It always heads for the target.
targeter: In charge of placing and timing out the target on the screen.
referee:  Watches the game at low priority and looks for players
          hitting the target, or running into the walls.

Interaction between the processes is handled by using the existing
Xinu low level message passing, or the new "wide" messages for
communicating with the plotter.

Since Xinu does not support anything like "curses", it is necessary to
hard code the strings necessary to clear the screen, and to position
the cursor to a random point on the screen.  These constants are given
in the file "game.h", and presently work on xterm, vt100, and raw Sun
terminals.
	  
Shawn Ostermann