////////////////////////////////////////////////////////////////////////////
//                                Dúshlán                                 //
//                    Copyright (c)2016 Peter McQuillan                   //
//                          All Rights Reserved.                          //
//      Distributed under the BSD Software License (see license.txt)      //
////////////////////////////////////////////////////////////////////////////

This package contains the source code for the game 'Dúshlán'.
Dúshlán is the Irish for 'Challenge'.
This game is written in 6502 assembly for the Nintendo Entertainment System (NES).

The code was developed using the ASM6 assembler.

There is a NES file included in the package that can be used on an emulator,
or an a real NES using a Flash cart like Powerpak or Everdrive.

The game itself is based on the classic Tetris, but with a few twists on the 
game and some extra features that are not commonly available like ghost (where
you can see where your piece would go if you dropped it) and save (where you 
can swap a piece in play for later usage).

There are two possible button controls for the game, the normal controls are

LEFT     -  Move left
RIGHT    -  Move right
DOWN     -  Drop piece
UP       -  Swap/Save a piece for later usage
A        -  Rotate piece clockwise
B        -  Rotate piece anticlockwise
START    -  Pause/Resume game
SELECT   -  Enable/Disable ghost mode

There is also an alternate control system available on the main menu, these
are the button definitions for it:

LEFT     -  move left
RIGHT    -  move right
DOWN     -  Rotate piece clockwise
UP       -  Rotate piece anticlockwise
A        -  Drop piece
B        -  Swap/Save a piece for later usage
START    -  Pause/Resume game
SELECT   -  Enable/Disable ghost mode

You are able to modify the behaviour of the 'Drop piece' key in the settings 
on the main menu. The three possible options are

Full - Pressing the drop key will cause the piece to fall down the screen as far as 
possible
While Held - This will cause the piece to drop as long as the drop key is pressed 
(effectively works like a down key)
Mixture - If you quickly press/tap the drop key, the piece will fall down the screen
as far as possible, however holding the drop key will drop the piece as long as the 
drop key is pressed - therefore a mixture of 'Full' and 'While Held'

Thanks to Teuthida for the music and sound effects.
Thanks to Derek Andrews for the ggsound sound engine
Thanks also to Shiru, Drag, Damian Yerrick and Joe Granato for some code snippets used.

Please direct any questions or comments to [email protected]