Ti-89 Chess4
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Programmed by: Richard Hambleton

For Questions/Comments email: hambleton.5@osu.edu


Overview:
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Chess 4 is a two player chess game for the ti-89 written in basic.  Player's select pieces using a coordinate grid system.  The program then verify that the move complies with the rules of chess.

Installation:
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1) Create a folder on your ti-89 called "chess4" (without quotes)
2) transfer all files (except this readme file) into that folder on your calculator.

The program is now ready to play


Instructions:
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The progam will immediately display the chess board, and after a brief initialization, prompt for White's move.

To enter a move simply type the cooardinates of the piece you wish to move, followed by the coordinates of the square to which you wish to move it.  For example:  a2 -> a4, or c1 -> e3

*WHEN ENTERING MOVES PLAYERS DO NOT NEED TO WORRY ABOUT THE "alpha" KEY.  The program automatically accepts only those values that make sense.*

After a player enters a move, there will be a short pause while the program checks to make sure the move is legal.

	- if the move is legal the program will prompt for black's first move.  Black moves are entered in the same manner as white's.
	
	- if the move is illegal, the program will reprompt white for their move.
	
Pressing ESC at anytime exits the program.

Castling:
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If a player wishes to castle, when the program prompts them for their move, they must simply press "0" (zero).  The program will then ask whether they wish to castle on the King or Queen side.  The player simply enteres either "K" or "Q" accordingly.  The program then makes sure that the move is legal, and then performs the castle.

	- In order to castle, the king, and involved rook must not have been moved since the beginning of the game
	
	- in order to castle, all squares between the king and involved rook must be clear.


**En Passant is not currently supported
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Features / short comings:
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	- the program validates each move.
		- bishops only go diagonally
		- rooks only straight
		- pawns only forward
		- pawns take diagonally
		- king only one square
		- etc.
	- Pawn Promotion
		- a pawn that makes it across the board, becomes a queen
	
	- Castling
		- see above for instructions on castling.
	
	- Currently the program does NOT check in anyway for CHECK, or 
	  CHECKMATE situations.  It is left to the user's to recognize
	  these situations and move accordingly.