Game variables

80:81	Note1	Tone value for note 1
82:83	Note2	Tone value for note 2
84:85	NoteC1	Note1 tally count
86:87	NoteC2	Note2 tally count
88	BitPos	Pixel position while printing, neighbor count in maze generation
89	BitPosSrc	Pixel position of the source while drawing the magnifier
8A:8B	HeadCellList	Start of the list of cells needing visiting in the maze draw
8C:8D	EndCellList	End of the list (+1) of cells needing visiting
8E:8F	Temp1	Used to check coordinates and other
90:91	RndSeed	Used to fetch bytes from ROM as random numbers
92	RequestedPage	Upper byte of address of visible screen page (04, 10, or 1C)
93:94	GenDirection	Current direction in maze generation
95:96	TargetCell	The target cell last used by the open-cell-wall function
97	WallOpened	Maze generation. 00 if a wall was opened during the dig run
98	Temp2	General use
99	Temp3	General use (used as a counter in finding possible directions for a bug)
9A:9B	DrawingScreenPtr	The screen that is currently being drawn on (1000 or 1C00)
9C:9D	VisibleScreenPtr	The screen that is currently being shown (1000 or 1C00)
9E:9F	ScreenPtr	Pointer to the screen buffer being drawn on (1000, 1C00, or 0400)
A0	NumBugs	Number of bugs in game
A1	MouthOpen	0 if mouth is open or 1 if mouth is closed. Used as a temporary between rounds.
A2:A3	PlayerCoords	Player's coordinates on the screen (y,x)
A4	PlayerDir	Player's facing direction
A5	HorzDoubler	Flag used to double the horizontal pixels when magnified
A6	Temp4	Used with A5 as a temporary word
A7:A8	MagnifierStart	Starting point screen pointer of the magnifier
A9:AA	MagnifierEnd	The last screen pointer of the magnifier
AB:AC	PixCoords	Coordinates on the screen (y,x)
AD	ColorMask	A color mask for printing characters
AE	ChangeColor	Rotate the color mask after every character (for splash)
AF	NumMinutes	Number of minutes in game time BCD
B0	NumSeconds	Number of seconds in game time BCD
B1:B2	Score	Game score BCD
B3:B4	HighScore	High score BDC
B5	LiveOrDemo	0 if demo game, not 0 if live game
B6	ISRCountScore	Counts ISRs in live game mode to decrement score once a second
B7	ISRCountTime	Counts ISRs in live game to increment the time once a second
B8	DrawScore	0 to skip drawing the score or non-zero to draw it
B9	DrawCountSecs	0 to skip drawing seconds-count or non-zero to draw it
BA	MakeEatSound	Non-zero to play the eat-dot-sound
BB	EatSnd1	Used in timing the sound effect for eating-a-dot
BC	EatSnd2	Used in timing the sound effect for eating-a-dot
BD	EatSnd3	Used in timing the sound effect for eating-a-dot
BE:BF	DotsLeft	Number of dots left to be eaten in the maze
C0	MazeLoopiness	Controls the loopiness of the maze. If RND>=<$C0 then dead-end, otherwise a loop. Starts at $C0 and divides by two each level (more dead-ends)
C1	ShowingGame	FF if game screen is showing. 00 if other things are being shown.
C2	JoyOrKey	FF if player is using joystick or 00 if player is using keyboard
C3:C4	DemoTimer	Count-down by the ISR used to time the demo play (and direct restart after losing)
C5	NumStartBugs	Hold ENTER down at powerup to start the game with 16 bugs
C6	PlayShortSong	00 if we should play the long song or FF if we already have (and should play the short song)
C7	VisiblePage	Upper byte of address of visible screen page

Graphics pages (3K each)

• 0400 - 0FFF
• 1000 - 1BFF
• 1C00 - 27FF

The data on the bugs is kept in an array at $2808. 3 bytes each: y,x,dir

• 2800:2807: during maze generation, list of unvisited neighbors (2 bytes * 4 possible)
• 2808:2868: 1st set of data on up to 32 bugs ... 3 bytes each (y,x,dir)
• 2868:28C7: 2nd set (starts as a duplicate of 1st) of bug data (y,x,dir). Two sets of data for mouth open/close times
• 28C8:28E7: column-has-content flags set by the draw-magnifier routine and read by the draw-bug routine
• 28E8:2A27: array of bytes, one per cell, 20*10 cells. 00=not visited, FF=visited
• 2A28:? : array of words, coordinates of cells we need to revisit in the maze generation