A.N.A.L.O.G. ISSUE 50 / JANUARY 1987 / PAGE 28

Krazy Katerpillars

Larvicide won’t be enough when you’re
up against these vermiform villains.

Krazy Katerpillars is a fast-action arcade-type game. Your job is to clear the screen of the swarming katerpillars before they do you in. Though you start out in the screen center, in a zone clear of the bugs, you’re surrounded—above and below. Katerpillars begin to move across the screen, advancing on you. Shoot as many as possible, while trying to outmaneuver the rest. Be careful. If you miss your target, your missile cycles to the screen bottom and forms a deadly spike that heads straight toward you.

Typing it in.

Listing 1 is the BASIC data used to create both cassette and disk versions of Krazy Katerpillars. Those readers who are interested in how the game works may obtain the assembly listing on either the magazine disk version or the ANALOG Computing Atari Users’ Group on Delphi.

Disk users should refer to the M/L Editor article on page 10 for typing instructions.

If you have a cassette system, type in Listing 1, then add the lines shown in Listing 2. Type RUN and press RETURN. The program will begin checking the data statements, printing the line numbers as it goes. It will alert you to any problems. Fix any incorrect lines and rerun the program until all errors are eliminated.

When all your data lines are correct, the computer will beep twice and prompt you to READY CASSETTE AND PRESS RETURN. Now, insert a blank cassette in your recorder, press the RECORD and PLAY buttons simultaneously, and hit RETURN. The message WRITING FILE will appear, and the program will create a machine language boot tape version of Krazy Katerpillars, printing each data line number as it goes. When the READY prompt appears, the game is recorded and ready to play. CSAVE the BASIC program onto a separate tape before continuing.

To play the game, rewind the tape created with the BASIC program to the beginning. Turn your computer off and remove all cartridges. Press the PLAY button on your recorder and turn on your computer, while holding down the START key. If you have an XL or XE series computer, you must hold the START and OPTION keys when you turn on the power. The computer will beep once. Hit the RETURN key, and Krazy Katerpillars will load and run automatically.

Rules.

When the title screen appears, use the SELECT key to choose a starting level, 1-9, then press START to begin playing.

In Krazy Katerpillars, you have four lives. The number remaining is shown in the upper right corner, under your level. Contact with any creature or a spike will take one life. A level is completed when all the Katerpillars have been destroyed. The larvae going off the screen’s bottom will cycle back to the top and reappear.

Any of your missiles that reach the top of the screen are reset to the bottom and become spikes. Remember, contact with a spike is deadly. Spikes can be useful, though, for killing Katerpillars—the tip is deadly to them.

When over, the game may be restarted at the original starting level by pressing the fire button. To pick a new level, press START. The title screen will appear, with the level selector.

Hints.

Go with the flow of bugs from left to right. Try to shoot and maneuver your way up above the top layer. Then destroy the Katerpillars, using the spikes. On higher levels, you have to do this; it’s impossible to shoot them all on the first run-through.

Listing 1.

1000 DATA 255,255,0,32,181,39,76,181,32,112,112,112,112,112,71,33,3613
1010 DATA 32,112,7,112,112,112,6,112,112,6,112,112,112,112,112,112,4045
1020 DATA 112,6,48,6,65,3,32,0,0,0,0,0,0,0,43,114,4348
1030 DATA 161,58,121,0,0,0,0,0,0,0,0,0,0,0,0,43,2358
1040 DATA 97,180,37,114,176,41,108,172,33,114,179,0,0,0,0,0,8728
1050 DATA 0,0,0,0,0,0,0,0,226,249,0,0,0,0,0,0,5574
1060 DATA 0,0,0,0,0,0,0,0,228,225,246,233,228,0,232,245,1228
1070 DATA 230,230,0,0,0,0,0,0,0,0,0,243,229,236,229,227,8024
1080 DATA 244,0,236,229,246,229,236,0,0,0,0,0,0,0,0,240,1044
1090 DATA 242,229,243,243,0,243,244,225,242,244,0,0,0,0,0,0,3075
1100 DATA 0,0,0,0,112,112,112,70,0,48,134,197,40,48,133,133,3309
1110 DATA 133,133,133,133,133,133,133,133,65,158,32,216,169,72,141,196,9463
1120 DATA 2,169,40,141,197,2,169,120,141,198,2,169,104,141,199,2,6926
1130 DATA 169,0,141,200,2,169,3,141,48,2,169,32,141,49,2,162,2531
1140 DATA 31,169,0,149,176,202,16,251,162,0,138,157,0,6,202,208,7619
1150 DATA 250,169,40,133,194,169,48,133,195,32,230,37,162,8,169,0,5576
1160 DATA 157,0,210,202,16,250,32,101,228,160,115,162,38,169,7,32,5705
1170 DATA 92,228,162,1,142,11,6,173,198,2,72,162,1,189,196,2,4579
1180 DATA 157,197,2,202,16,247,104,141,196,2,169,15,141,24,6,173,4813
1190 DATA 31,208,41,1,240,52,173,24,6,208,244,173,31,208,41,2,5535
1200 DATA 208,18,238,11,6,169,170,141,7,210,169,121,141,6,210,169,8809
1210 DATA 10,141,8,6,173,11,6,201,10,144,5,169,1,141,11,6,9992
1220 DATA 9,208,162,97,157,33,32,76,17,33,206,11,6,174,11,6,9990
1230 DATA 142,10,6,142,12,6,169,224,133,198,169,40,133,200,169,0,7629
1240 DATA 133,197,133,199,162,1,160,0,177,197,145,199,136,208,249,230,4539
1250 DATA 198,230,200,202,16,240,162,39,189,101,39,157,0,40,202,16,5152
1260 DATA 247,169,28,141,196,2,169,136,141,197,2,169,204,141,198,2,8673
1270 DATA 169,42,141,199,2,169,0,141,200,2,169,158,141,48,2,169,5708
1280 DATA 32,141,49,2,169,103,141,0,2,169,37,141,1,2,169,192,3654
1290 DATA 141,14,212,169,40,141,244,2,169,3,141,29,208,169,62,141,7247
1300 DATA 47,2,169,40,141,7,212,169,16,141,111,2,162,0,142,8,2764
1310 DATA 208,142,12,208,169,44,133,177,169,43,133,191,32,163,37,162,7677
1320 DATA 39,189,141,39,157,0,48,202,16,247,162,0,142,16,6,142,3881
1330 DATA 17,6,142,18,6,32,217,36,162,4,142,23,6,32,0,36,8324
1340 DATA 162,1,142,0,6,142,30,208,32,117,36,32,225,34,32,217,4277
1350 DATA 36,32,105,36,32,225,34,32,82,38,173,9,6,240,3,32,1037
1360 DATA 0,36,173,13,6,240,3,76,71,34,76,34,34,169,0,141,1389
1370 DATA 0,6,141,13,6,160,17,185,46,39,145,176,136,16,248,169,7373
1380 DATA 32,141,4,210,169,34,141,7,6,173,7,6,208,251,32,163,5877
1390 DATA 37,206,23,6,173,23,6,240,23,32,37,37,32,230,37,32,978
1400 DATA 250,37,32,203,37,169,1,141,30,208,141,0,6,76,34,34,1063
1410 DATA 162,8,189,92,39,157,25,48,202,16,247,32,230,37,169,10,5501
1420 DATA 141,15,6,32,44,38,169,10,141,15,6,230,195,32,44,38,1944
1430 DATA 198,195,173,31,208,41,1,208,10,173,31,208,41,1,240,249,8406
1440 DATA 76,181,32,173,132,2,240,16,173,24,6,208,229,32,117,36,5261
1450 DATA 169,10,141,24,6,76,172,34,174,12,6,142,10,6,142,11,96
1460 DATA 6,32,230,37,76,249,33,162,3,189,8,208,240,6,238,13,7252
1470 DATA 6,76,251,35,202,16,242,162,3,189,0,208,240,3,32,208,8000
1480 DATA 35,202,16,245,162,1,142,30,208,162,3,173,27,6,61,252,5980
1490 DATA 35,240,3,32,110,35,202,16,242,173,4,6,240,6,206,4,4826
1500 DATA 6,76,251,35,169,4,141,4,6,173,132,2,240,3,76,251,6017
1510 DATA 35,162,3,173,27,6,61,252,35,208,15,189,252,35,13,27,4405
1520 DATA 6,141,27,6,32,74,35,76,251,35,202,16,230,76,251,35,6772
1530 DATA 169,166,141,1,210,169,15,141,5,6,165,178,24,105,3,157,4150
1540 DATA 4,208,149,181,56,165,176,233,5,149,185,169,65,157,28,6,6654
1550 DATA 32,110,35,96,181,185,133,190,222,28,6,240,53,189,32,6,5892
1560 DATA 208,14,160,2,189,252,35,73,255,49,190,145,190,136,16,244,703
1570 DATA 56,165,190,233,3,133,190,149,185,201,50,144,13,160,2,177,8017
1580 DATA 190,29,252,35,145,190,136,16,246,96,169,255,149,185,157,32,1156
1590 DATA 6,96,160,0,169,0,133,190,189,252,35,73,255,49,190,145,217
1600 DATA 190,136,208,244,169,0,157,28,6,157,32,6,189,252,35,77,5620
1610 DATA 27,6,141,27,6,96,32,172,35,181,185,133,190,181,181,133,9989
1620 DATA 189,142,3,6,32,159,36,169,0,145,192,200,145,192,169,32,8426
1630 DATA 141,21,6,169,168,141,3,210,169,11,141,6,6,174,3,6,1803
1640 DATA 96,96,3,12,48,192,248,24,173,10,6,105,1,141,10,6,521
1650 DATA 216,169,0,141,0,6,141,9,6,238,11,6,173,11,6,201,2199
1660 DATA 16,144,5,169,14,141,11,6,174,11,6,189,89,36,141,14,1706
1670 DATA 6,169,168,141,7,210,169,200,141,6,210,169,80,141,8,6,6057
1680 DATA 32,163,37,32,37,37,32,217,36,32,250,37,32,203,37,169,4999
1690 DATA 150,141,24,6,173,24,6,208,251,169,1,141,0,6,96,0,2109
1700 DATA 30,25,20,25,17,10,15,12,10,10,7,6,5,5,4,174,5604
1710 DATA 14,6,160,255,136,208,253,202,208,248,96,162,2,142,25,6,8388
1720 DATA 160,255,230,195,177,194,170,198,195,160,0,142,26,6,177,194,9923
1730 DATA 170,173,26,6,145,194,200,208,242,230,195,206,25,6,208,233,3653
1740 DATA 198,195,198,195,96,56,165,189,233,48,74,74,170,169,0,141,8296
1750 DATA 1,6,56,165,190,233,48,41,240,74,141,2,6,10,10,46,1182
1760 DATA 1,6,24,109,2,6,133,192,173,1,6,105,0,133,193,24,2828
1770 DATA 169,40,101,192,133,192,169,48,101,193,133,193,138,168,96,248,2646
1780 DATA 24,162,2,189,16,6,125,19,6,157,16,6,202,16,244,216,5871
1790 DATA 162,2,169,0,157,19,6,202,16,250,162,6,160,0,185,16,4629
1800 DATA 6,32,14,37,232,232,200,192,3,208,243,162,17,173,10,6,7161
1810 DATA 32,14,37,96,141,22,6,41,15,9,16,157,1,48,173,22,9489
1820 DATA 6,74,74,74,74,9,16,157,0,48,96,169,45,133,180,169,5699
1830 DATA 38,133,179,162,3,169,0,157,0,208,202,208,250,169,26,141,664
1840 DATA 193,2,141,194,2,141,195,2,162,2,160,13,185,32,39,145,4625
1850 DATA 179,136,16,248,230,180,202,16,241,174,23,6,202,240,9,189,492
1860 DATA 99,37,157,0,208,202,208,247,96,0,176,183,190,72,138,72,9884
1870 DATA 152,72,166,196,189,141,37,188,152,37,141,10,212,141,22,208,8799
1880 DATA 140,23,208,230,196,224,11,208,4,162,0,134,196,104,168,104,9127
1890 DATA 170,104,64,134,198,24,86,126,182,70,42,6,102,14,14,26,760
1900 DATA 60,28,136,202,122,70,28,60,168,169,0,133,190,162,5,169,7253
1910 DATA 0,168,145,190,136,208,251,230,191,202,208,246,169,43,133,191,5795
1920 DATA 162,3,169,0,157,32,6,157,28,6,141,27,6,202,16,244,4107
1930 DATA 96,169,128,133,176,169,100,141,0,208,133,178,169,14,141,192,261
1940 DATA 2,160,13,185,32,39,145,176,136,16,248,96,162,1,169,0,5777
1950 DATA 168,145,194,136,208,251,230,195,202,16,246,169,48,133,195,96,2909
1960 DATA 32,35,38,230,195,32,35,38,198,195,24,165,194,105,160,133,9308
1970 DATA 194,165,195,105,0,133,195,160,160,169,0,145,194,136,208,251,3374
1980 DATA 169,40,133,194,169,48,133,195,96,174,11,6,189,66,38,141,6032
1990 DATA 15,6,172,10,210,32,56,38,206,15,6,16,245,96,162,4,3796
2000 DATA 138,145,194,136,202,208,249,96,0,6,10,15,25,16,10,20,9692
2010 DATA 22,25,25,27,30,30,35,35,162,1,160,0,177,194,208,15,4725
2020 DATA 136,208,249,230,195,202,16,244,162,1,142,9,6,208,5,162,7285
2030 DATA 0,142,9,6,169,48,133,195,96,216,174,24,6,240,3,206,7994
2040 DATA 24,6,174,5,6,240,11,189,64,39,141,0,210,206,5,6,3979
2050 DATA 208,5,169,0,141,1,210,174,6,6,240,11,189,80,39,141,5652
2060 DATA 2,210,206,6,6,208,5,169,0,141,3,210,173,7,6,240,6029
2070 DATA 9,74,141,5,210,206,7,6,208,5,169,0,141,5,210,174,6671
2080 DATA 8,6,240,5,206,8,6,208,5,169,0,141,7,210,173,0,4677
2090 DATA 6,208,3,76,98,228,173,4,208,240,6,238,13,6,76,205,7793
2100 DATA 38,166,178,164,176,173,120,2,74,176,2,136,136,74,176,2,5990
2110 DATA 200,200,74,176,2,202,202,74,176,2,232,232,224,50,144,11,9752
2120 DATA 224,208,144,2,162,50,134,178,142,0,208,192,90,144,6,192,8890
2130 DATA 185,176,2,132,176,160,13,185,32,39,145,176,136,16,248,169,9413
2140 DATA 0,133,77,76,205,38,0,0,8,8,8,28,28,62,62,62,7924
2150 DATA 62,62,0,0,8,16,74,34,72,68,16,133,16,4,162,20,9376
2160 DATA 69,18,72,18,8,16,230,240,250,255,230,200,180,170,150,130,4999
2170 DATA 100,75,65,50,45,40,120,100,90,80,75,70,50,40,30,20,175
2180 DATA 10,5,167,161,173,165,0,175,182,165,178,0,0,0,0,0,1846
2190 DATA 0,0,0,0,12,51,86,90,86,51,12,0,204,51,149,165,3535
2200 DATA 149,51,204,0,204,51,86,90,86,51,204,0,192,48,148,165,7267
2210 DATA 148,48,192,115,99,111,114,101,0,0,0,0,0,0,0,0,6257
2220 DATA 108,118,108,0,0,0,0,0,0,0,0,0,0,0,0,0,2888
2230 DATA 0,0,0,0,0,0,0,0,0,0,0,0,0,255,0,255,9880
2240 DATA 37,224,2,225,2,0,32,0,0,0,0,0,0,0,0,0,3865

BASIC listing.

10 REM *** KRAZY KATERPILLARS ***
20 REM CASSETTE MAKER PROGRAM
40 DIM DAT(16):LINE=990:RESTORE 10000:TRAP 120:? "CHECKING DATA"
50 LINE=LINE+10:? "LINE :"; LINE : FOR X=1 TO 16:READ DAT:IF DAT<0 OR DAT>255 THEN 220
60 DAT(X)=DAT:NEKT X:DATLIN=PEEK(183)+PEEK(843)*256:IF DATLIN<>LINE THEN ? "LINE ";LINE;" MISSING !":END
70 TOTAL=LINE:FOR X=1 TO 16
80 IF PASS=0 THEN PUT #1,DAT(X):NEXT X:READ CHKSUM:GOTO 50
90 TOTAL=TOTAL+DAT(X)*X:IF TOTAL>9999 THEN TOTAL=TOTAL−10000
100 NEXT X:READ CHKSUM:IF TOTAL=CHKSUM THEN 50
110 GOTO 220
120 IF PEEK(195)<>6 THEN 220
130 IF PASS=0 THEN 200
160 FOR X=1 TO 128:PUT #1,0:NEXT X:CLOSE #1:END
200 ? "READY CASSETTE AND PRESS RETURN";:OPEN #1,8,128,"C:":RESTORE 230:FOR X=1 TO 40:READ N:PUT #1,N:NEXT X
210 ? :? "WRITING FILE":PASS=2:LINE=990:RESTORE 1000:TRAP 120:GOTO 50
220 ? "BAD DATA: LINE ";LINE:END
230 DATA 0,16,210,31,249,31,169,0,234,234,234,169,60,141,2,211,169,0,141,231,2,133,14,169,86,141,232,2
240 DATA 133,15,169,0,133,10,169,32,13

Assembly listing.

;KRAZY KATERPILLARS
;DAVID HUFF
;
;
;RUN ADDRESS: $2000
;
;
	.OPT	NOEJECT
	.TAB	12,17,28
;
;SYSTEM EQUATES
;
HPOSP0	=	$D000
HPOSM0	=	$D004
SIZEP0	=	$D008
SIZEM	=	$D00C
M0PF	=	$D000
P0PF	=	$D004
M0PL	=	$D008
PMBASE	=	$D407
HITCLR	=	$D01E
GRACTL	=	$D01D
SDMCTL	=	$022F
GPRIOR	=	$026F
SDLSTL	=	$0230
VDSLST	=	$0200
CHBAS	=	$02F4
STICK0	=	$0278
STRIG0	=	$0284
PCOLR0	=	$02C0
COLOR0	=	$02C4
ATRACT	=	$4D
COLPF0	=	$D016
AUDCTL	=	$D208
AUDF1	=	$D200
AUDC1	=	$D201
AUDF2	=	$D202
AUDC2	=	$D203
AUDF3	=	$D204
AUDC3	=	$D205
AUDF4	=	$D206
AUDC4	=	$D207
RANDOM	=	$D20A
XITVBV	=	$E462
SETVBV	=	$E45C
SIOINV	=	$E465
NMIEN	=	$D40E
WSYNC	=	$D40A
CONSOL	=	$D01F
;
;PROGRAM REGISTERS
;
	*=	$B0
;
VP0LO	*=	*+1	;Y POS. PLAYER0
VP0HI	*=	*+1
SHP0	*=	*+1	;X POS. PLAYER0
VP1LO	*=	*+1	;Y POS. PLAYER1
VP1HI	*=	*+1
SHM0	*=	*+4	;X POS. MISSILES
VPMLO	*=	*+4	;Y POS. MISSILES
HPOSM	*=	*+1	;X POS. COLLISION
VPM0LO	*=	*+1	;Y POS. COLLISION
VPM0HI	*=	*+1
COLLO	*=	*+1	;COLLISION ADDR
COLHI	*=	*+1
DMLO	*=	*+1	;START SCREEN MEM
DMHI	*=	*+1
DLCNT	*=	*+1	;DLI COUNTER
OLDSET	*=	*+2	;ADDR ROM CHSET
NEWSET	*=	*+2	;ADDR NEW CHSET
;
	*=	$0600
;
STOP	*=	*+1	;PLAYER MOVEMENT?
TEMPHI	*=	*+1	;TEMPS
LOX8	*=	*+1
SAVEX	*=	*+1
TRGCNT	*=	*+1	;READ TRIGGER?
M0SND	*=	*+1	;SOUNDS
HITSND	*=	*+1
P0SND	*=	*+1
LVLSND	*=	*+1
LVLFLG	*=	*+1	;NEW LEVEL?
LEVEL	*=	*+1	;BCD LEVEL #
LEVHEX	*=	*+1	;HEX LEVEL #
LEVORG	*=	*+1	;ORIGINAL LEVEL
P0DEAD	*=	*+1	;PLAYER DEAD?
SPEED	*=	*+1	;BUGS SPEED
BUGCNT	*=	*+1	;# OF BUGS
SCORE	*=	*+3	;SCORE
SCOADD	*=	*+3	;ADD TO SCORE
DIGIT	*=	*+1	;FOR DISPLAY
LIVES	*=	*+1	;LIVES
TIMER	*=	*+1	;DELAY TIMER
CPYCNT	*=	*+1	;PAGES TO MOVE
CPYTMP	*=	*+1	;TEMP
MSTAT	*=	*+1	;WHICH MISSILES OUT
MSTOP	*=	*+4	;DISTANCE TO GO
SPKFLG	*=	*+4	;SPIKE ON?
;
PMB	=	$2800	;PMBASE ADDRESS
CHBASE	=	PMB	;CHARACTER SET BASE
SCOMEM	=	$3000	;SCORE LINE
DMEM	=	SCOMEM+40	;DISPLAY MEMORY
;
;
	*=	$2000
;
	JMP	START
;
;
;DISPLAY LIST FOR TITLE
;
DLTITL	.BYTE	$70,$70,$70,$70,$70
	.BYTE	$47
	.WORD	TITLE
	.BYTE	$70,7,$70,$70,$70,6,$70,$70,6
	.BYTE	$70,$70,$70,$70,$70,$70,$70,6,$30,6
	.BYTE	$41
	.WORD	DLTITL
;
;
;TITLE MEMORY
;
TITLE
	.BYTE	0,0,0,0,0,0,0,43,114,161,58,121
	*=	*+12
	.BYTE	43,97,180,37,114,176,41
	.BYTE	108,172,33,114,179
	*=	*+13
	.BYTE	226,249
	*=	*+14
	.BYTE	228,225,246,233,228,0,232,245,230,230
	*=	*+9
	.BYTE	243,229,236,229,227,244,0
	.BYTE	236,229,246,229,236
	*=	*+8
	.BYTE	240,242,229,243,243,0
	.BYTE	243,244,225,242,244
	*=	*+10
;
;
;GAME DISPLAY LIST
;
DLIST	.BYTE	$70,$70,$70
	.BYTE	$46
	.WORD	SCOMEM
	.BYTE	$86,$C5
	.WORD	DMEM
	.BYTE	$85,$85,$85,$85,$85,$85,$85,$85,$85,$85
	.BYTE	$41
	.WORD	DLIST
;
;
START	CLD
	LDA	#72	;TITLE COLORS
	STA	COLOR0
	LDA	#40
	STA	COLOR0+1
	LDA	#120
	STA	COLOR0+2
	LDA	#104
	STA	COLOR0+3
	LDA	#0	;BACKGND
	STA	COLOR0+4
;
	LDA	#DLTITL&$FF	;SHOW TITLE
	STA	SDLSTL
	LDA	#DLTITL/256
	STA	SDLSTL+1
;
	LDX	#31	;CLEAR PAGE0 REGISTERS
	LDA	#0
CLRP0	STA	$B0,X
	DEX
	BPL	CLRP0
;
	LDX	#0	;CLEAR PAGE6
	TXA
CLRP6	STA	$0600,X
	DEX
	BNE	CLRP6
;
	LDA	#DMEM&$FF	;SET POINTER TO
	STA	DMLO	;SCREEN MEMORY
	LDA	#DMEM/256
	STA	DMHI
	JSR	CLRSM	;CLEAR PLAYFIELD
;
	LDX	#8	;INITIALIZE SOUNDS
	LDA	#0
NOSND	STA	AUDF1,X
	DEX
	BPL	NOSND
	JSR	SIOINV
;
	LDY	#VBLANK&$FF	;START VBI
	LDX	#VBLANK/256
	LDA	#7
	JSR	SETVBV
;
	LDX	#1	;SET LEVEL
	STX	LEVHEX
;
;
;ROTATE TITLE COLORS
;
ROTCOL	LDA	COLOR0+2	;GET COLOR2
	PHA		;SAVE IT
	LDX	#1
COLR	LDA	COLOR0,X	;GET COLOR
	STA	COLOR0+1,X	;MOVE IT
	DEX		;NEXT COLOR
	BPL	COLR
	PLA		;GET COLOR2
	STA	COLOR0	;TO COLOR0
;
	LDA	#15	;DELAY
	STA	TIMER
TM	LDA	CONSOL
	AND	#1	;CHECK START
	BEQ	BEGIN	;PRESSED, BEGIN GAME
	LDA	TIMER	;TIME UP?
	BNE	TM	;NO
;
	LDA	CONSOL
	AND	#2	;CHECK SELECT
	BNE	SHOLEV	;NOT PRESSED
	INC	LEVHEX	;PRESSED
	LDA	#$AA	;BEEP
	STA	AUDC4
	LDA	#121
	STA	AUDF4
	LDA	#10	;DURATION
	STA	LVLSND
SHOLEV	LDA	LEVHEX	;GET LEVEL
	CMP	#10	;TO BIG?
	BCC	OKLEV	;NO
	LDA	#1	;YES,RESET
	STA	LEVHEX
OKLEV	ORA	#$D0	;COLOR3
	LDX	#97
	STA	TITLE,X	;DISPLAY IT
	JMP	ROTCOL	;TITLE ROUTINE
;
BEGIN	DEC	LEVHEX	;WANT (0-9)
	LDX	LEVHEX	;START LEVEL
	STX	LEVEL
	STX	LEVORG	;KEEP ORIGINAL LEVEL
;
;
;REDEFINE CHARACTERS
;
	LDA	#$E0	;ADDR ROM CHSET
	STA	OLDSET+1
	LDA	#CHBASE/256	;NEW CHBASE
	STA	NEWSET+1
	LDA	#0	;LOW BYTES
	STA	OLDSET
	STA	NEWSET
;
	LDX	#1	;DO 2 PAGES OF CHSET
CH1	LDY	#0
CH2	LDA	(OLDSET),Y	;GET ROM
	STA	(NEWSET),Y	;PUT IN RAM
	DEY
	BNE	CH2
	INC	OLDSET+1	;DO NEXT PAGE
	INC	NEWSET+1
	DEX
	BPL	CH1
;
NEWCH	LDX	#39	;REDEFINE CHARACTERS
NEW1	LDA	CHR1,X	;GET CHAR DATA
	STA	CHBASE,X	;MOVE IT
	DEX
	BPL	NEW1
;
;GAME COLORS
;
	LDA	#28	;SCORE NUMBERS
	STA	COLOR0
	LDA	#136	;SCORE LETTERS
	STA	COLOR0+1
	LDA	#204	;BUGS LEGS
	STA	COLOR0+2
	LDA	#42	;MISSILES
	STA	COLOR0+3
	LDA	#0	;BACKGND
	STA	COLOR0+4
;
	LDA	#DLIST&$FF	;GAME DISPLA ON
	STA	SDLSTL
	LDA	#DLIST/256
	STA	SDLSTL+1
;
	LDA	#DLI&$FF	;SET DLI VECTOR
	STA	VDSLST
	LDA	#DLI/256
	STA	VDSLST+1
;
	LDA	#$C0	;ENABLE DLI
	STA	NMIEN
;
	LDA	#CHBASE/256	;SWITCH CHAR BASE
	STA	CHBAS
;
	LDA	#3	;ENABLE P/M
	STA	GRACTL
	LDA	#62	;SINGLE LINE RES.
	STA	SDMCTL
	LDA	#PMB/256	;HI BYTE PMBASE
	STA	PMBASE
	LDA	#16	;FIFTH PLAYER ENABLE
	STA	GPRIOR
	LDX	#0	;NORMAL SIZE
	STX	SIZEP0
	STX	SIZEM
	LDA	#PMB/256+4	;PLAYER0 BASE
	STA	VP0HI
	LDA	#PMB/256+3	;MISSILE BASE
	STA	VPM0HI
	JSR	CLRPM	;CLEAR P/M AREA
;
RESET	LDX	#39	;DISPLAY SCORE LINE
SCRLN	LDA	SCOLN,X
	STA	SCOMEM,X
	DEX
	BPL	SCRLN
;
	LDX	#0	;SCORE = 0
	STX	SCORE
	STX	SCORE+1
	STX	SCORE+2
	JSR	DISPSCO	;PUT ON SCORE
;
	LDX	#4	;4 LIVES
	STX	LIVES
	JSR	NEWLVL	;GET FIRST LEVEL
;
	LDX	#1	;ENABLE MOVEMENT
	STX	STOP
	STX	HITCLR	;CLEAR COLLISIONS
;
;
;
;MAIN LOOP
;
PLAY	JSR	COPY	;MOVE BUGS
	JSR	MFIRE	;MOVE MISSILES
	JSR	DISPSCO	;SHOW SCORE
	JSR	DELAY	;SLOW IT DOWN
	JSR	MFIRE	;MOVE AGAIN
	JSR	CKLEV	;CHECK LEVEL
	LDA	LVLFLG	;COMPLETE?
	BEQ	CHKP0	;NO
	JSR	NEWLVL	;YES,DO NEXT LEVEL
;
CHKP0	LDA	P0DEAD	;PLAYER DEAD
	BEQ	ALIVE	;NO
	JMP	KILLP0	;YES,EXPLOSION
;
ALIVE	JMP	PLAY	;CONTINUE GAME
;
;
;PLAYER KILLED
;
KILLP0	LDA	#0	;NO MOTION
	STA	STOP
	STA	P0DEAD	;RESET FLAG
;
	LDY	#17	;SHOW EXPLOSION
EXP	LDA	EXPLODE,Y	;DATA
	STA	(VP0LO),Y	;SHOW IT
	DEY
	BPL	EXP
;
	LDA	#32	;TURN ON SOUND
	STA	AUDF3
	LDA	#34
	STA	P0SND
DLY	LDA	P0SND	;WAIT
	BNE	DLY
;
	JSR	CLRPM	;CLEAR P/M AREA
;
	DEC	LIVES	;LOSE A LIFE
	LDA	LIVES	;ANY LEFT?
	BEQ	DEAD	;NO
	JSR	DISPLIV	;YES,SHOW THEM
	JSR	CLRSM	;CLEAR SCREEN
	JSR	SETUP	;SETUP LEVEL
	JSR	STARTP0	;RESTART
	LDA	#1
	STA	HITCLR	;CLEAR COLLISION
	STA	STOP	;ALLOW MOVEMENT
	JMP	PLAY	;TO MAIN LOOP
;
;
;
; GAME OVER ROUTINE
;
DEAD	LDX	#8
DD1	LDA	MESSAGE,X	;GAME OVER
	STA	SCOMEM+25,X	;SHOW IT
	DEX
	BPL	DD1
;
	JSR	CLRSM	;CLEAR SCREEN
	LDA	#10
	STA	BUGCNT	;10 BUGS
	JSR	SET1	;SHOW THEM
	LDA	#10
	STA	BUGCNT	;10 BUGS
	INC	DMHI	;NEXT PAGE
	JSR	SET1	;SHOW THEM
	DEC	DMHI	;RESTORE
;
WAIT	LDA	CONSOL
	AND	#1	;START?
	BNE	WT1	;NO
WT2	LDA	CONSOL	;YES
	AND	#1	;RELEASED?
	BEQ	WT2	;NO
	JMP	START	;YES, DO TITLE
;
WT1	LDA	STRIG0	;PRESSED?
	BEQ	RESTART	;YES
	LDA	TIMER	;TIME UP?
	BNE	WAIT	;NO
	JSR	COPY	;MOVE BUGS
	LDA	#10	;RELOAD TIMER
	STA	TIMER
	JMP	WAIT	;KEEP CHECKING
;
RESTART	LDX	LEVORG	;ORIGINAL LEV
	STX	LEVEL	;RESET
	STX	LEVHEX
	JSR	CLRSM	;CLEAR SCREEN
	JMP	RESET	;RESTART
;
;
;
;
;SUBROUTINES
;
;
;MISSILE ROUTINES
;
MFIRE	LDX	#3	;DO 4 MISSILES
CKP0	LDA	M0PL,X	;PLAYER HIT?
	BEQ	NOMHIT	;NO
	INC	P0DEAD	;YES,SET FLAG
	JMP	FMEXIT	;DONE
NOMHIT	DEX		;NEXT MISSILE
	BPL	CKP0
;
	LDX	#3	;DO 4 MISSILES
CKM	LDA	M0PF,X	;BUG HIT?
	BEQ	NOHIT	;NO
	JSR	KILLBUG	;YES, DESTROY IT
NOHIT	DEX		;NEXT MISSILE
	BPL	CKM
;
	LDX	#1	;CLEAR COLLISIONS
	STX	HITCLR
;
	LDX	#3	;MOVE MISSILES IF OUT
FIREM	LDA	MSTAT	;MISSILE STATUS
	AND	MDATA,X	;IS IT OUT?
	BEQ	NOMOVE	;NO
	JSR	MOVEM	;YES, MOVE IT
NOMOVE	DEX		;NEXT ONE
	BPL	FIREM
;
TRIG	LDA	TRGCNT	;CHECK TRIG?
	BEQ	CKTRIG	;YES
	DEC	TRGCNT	;NO
	JMP	FMEXIT	;DONE
;
CKTRIG	LDA	#4	;RESET IT
	STA	TRGCNT
	LDA	STRIG0	;PRESSED?
	BEQ	LAUNCH	;YES, TRY TO FIRE
	JMP	FMEXIT	;NO
;
LAUNCH	LDX	#3
NEXTM	LDA	MSTAT	;ANY AVAILABLE?
	AND	MDATA,X	;CHECK BITS
	BNE	MOUT	;NO,ALREADY OUT
	LDA	MDATA,X	;YES
	ORA	MSTAT	;UPDATE MSTAT
	STA	MSTAT	;TO SHOW IT'S OUT
	JSR	STARTM	;START IT
	JMP	FMEXIT	;CAN ONLY FIRE 1
MOUT	DEX		;TRY NEXT ONE
	BPL	NEXTM
	JMP	FMEXIT
;
STARTM	LDA	#$A6	;MISSILE SOUND
	STA	AUDC1
	LDA	#15
	STA	M0SND
;
	LDA	SHP0	;GET PLAYERS X POS.
	CLC
	ADC	#3	;OFFSET
	STA	HPOSM0,X
	STA	SHM0,X	;SAVE MISSILE POS.
;
	SEC
	LDA	VP0LO	;PLAYERS VERT .POS
	SBC	#5	;OFFSET
	STA	VPMLO,X	;SAVE IT
;
	LDA	#65	;MOVE IT 65 TIMES
	STA	MSTOP,X
;
	JSR	MOVEM	;MOVE IT
	RTS
;
MOVEM	LDA	VPMLO,X	;GET Y
	STA	VPM0LO	;SAVE IT
;
	DEC	MSTOP,X	;DONE?
	BEQ	CLEARM	;YES, CLEAR IT
;
	LDA	SPKFLG,X	;SPIKE?
	BNE	SPIKE	;YES
	LDY	#2	;NO,ERASE OLD POS.
CLRM	LDA	MDATA,X	;GET BITS
	EOR	#$FF	;MAKE MASK
	AND	(VPM0LO),Y	;ZERO BITS
	STA	(VPM0LO),Y	;MISSILE OFF
	DEY
	BPL	CLRM
;
SPIKE	SEC
	LDA	VPM0LO	;OLD Y
	SBC	#3	;MOVE UP 3
	STA	VPM0LO
	STA	VPMLO,X	;SAVE NEW Y
	CMP	#50	;TOP LIMIT
	BCC	SPKON	;YES,SPIKE ON
	LDY	#2	;NO
LOADM	LDA	(VPM0LO),Y
	ORA	MDATA,X	;GET MISSILE BITS
	STA	(VPM0LO),Y	;MISSILE ON
	DEY
	BPL	LOADM
	RTS
;
SPKON	LDA	#255	;SPIKE ON
	STA	VPMLO,X	;MISSILE TO BOTTOM
	STA	SPKFLG,X	;SET FLAG
	RTS
;
CLEARM	LDY	#0	;ERASE A MISSILE
	LDA	#0
	STA	VPM0LO
CLM	LDA	MDATA,X	;GET MISSILE BITS
	EOR	#$FF	;MAKE MASK
	AND	(VPM0LO),Y	;ZERO BITS
	STA	(VPM0LO),Y	;TURN IT OFF
	DEY		;DO ALL OF MISSILE
	BNE	CLM
;
	LDA	#0	;RESET
	STA	MSTOP,X
	STA	SPKFLG,X
;
	LDA	MDATA,X	;MISSILE BITS
	EOR	MSTAT	;MISSILE NOT OUT
	STA	MSTAT	;UPDATE MSTAT
	RTS
;
;
KILLBUG	JSR	CLEARM	;HIT A BUG
	LDA	VPMLO,X	;GET Y POS.
	STA	VPM0LO
	LDA	SHM0,X	;GET X POS
	STA	HPOSM
;
	STX	SAVEX	;SAVE MISSILE #
	JSR	FIND	;GET MEMORY LOCATION
;
	LDA	#0	;ERASE THE BUG
	STA	(COLLO),Y	;FIRST PART
	INY
	STA	(COLLO),Y	;SECOND PART
;
	LDA	#$20	;UP SCORE
	STA	SCOADD+2
;
	LDA	#$A8	;SOUND ON
	STA	AUDC2
	LDA	#11
	STA	HITSND
	LDX	SAVEX	;RECOVER MISSILE #
	RTS
;
FMEXIT	RTS		TO MAIN LOOP
;
MDATA	.BYTE	3,12,48,192
;
;
;
;SHOW NEXT LEVEL
;
NEWLVL	SED		;BCD ADDITION
	CLC
	LDA	LEVEL	;BCD LEVEL
	ADC	#1
	STA	LEVEL
	CLD
;
	LDA	#0
	STA	STOP	;STOP MOVEMENT
	STA	LVLFLG	;RESET FLAG
;
	INC	LEVHEX	;HEX LEVEL
	LDA	LEVHEX
	CMP	#16	;TOO BIG?
	BCC	LEVOK	;NO
	LDA	#14	;YES
	STA	LEVHEX
LEVOK	LDX	LEVHEX	;INDEX
	LDA	LEVSPEED,X	;GET LEVEL SPEED
	STA	SPEED	;FOR COPY ROUTINE
;
	LDA	#$A8	;NEW LEVEL SOUND
	STA	AUDC4
	LDA	#200
	STA	AUDF4
	LDA	#80	;SOUND DURATION
	STA	LVLSND
;
	JSR	CLRPM	;CLEAR P/M
	JSR	DISPLIV	;SHOW LIVES
	JSR	DISPSCO	;SHOW SCORE
	JSR	SETUP	;NEXT LEVEL
	JSR	STARTP0	;START PLAYER
;
	LDA	#150	;DELAY BETWEEN LEVELS
	STA	TIMER
DLEV1	LDA	TIMER
	BNE	DLEV1
	LDA	#1
	STA	STOP	;ALLOW MOVEMENT
	RTS
;
LEVSPEED	.BYTE	0,30,25,20,25,17,10,15
	.BYTE	12,10,10,7,6,5,5,4
;
;
;
DELAY	LDX	SPEED	;SLOW IT DOWN
DE1	LDY	#255
DE2	DEY
	BNE	DE2
	DEX
	BNE	DE1
	RTS
;
;
;
;MOVE THE BUGS
;
COPY	LDX	#2	;DO 2 PAGES
	STX	CPYCNT
;
	LDY	#$FF
	INC	DMHI
	LDA	(DMLO),Y	;GET LAST BYTE
	TAX		;SAVE IT
	DEC	DMHI	;RESTORE
;
CPY1	LDY	#0	;SET TO FIRST BYTE
CPY2	STX	CPYTMP
	LDA	(DMLO),Y	;GET BYTE
	TAX		;STORE
	LDA	CPYTMP	;GET PREVIOUS BYTE
	STA	(DMLO),Y	;MOVE IT
	INY		;NEXT BYTE
	BNE	CPY2
;
	INC	DMHI	;NEXT PAGE
	DEC	CPYCNT	;DONE?
	BNE	CPY1	;NO
;
	DEC	DMHI	;YES,RESTORE
	DEC	DMHI
	RTS
;
;
;
;CALCULATE SCREEN MEMORY ADDRESS
;FROM P/M COORDINATES
;
FIND	SEC
	LDA	HPOSM	;X POS
	SBC	#48	;OFFSET
	LSR	A	;/2
	LSR	A	;/4
	TAX		;X COORD
;
	LDA	#0	;CLEAR
	STA	TEMPHI
;
	SEC		;Y=Y/16*40 BYTES/LINE
	LDA	VPM0LO	;Y POS
	SBC	#48	;OFFSET
	AND	#$F0	;Y/16*16
	LSR	A	;SHIFT RIGHT (*8)
	STA	LOX8	;SAVE *8
;
	ASL	A	;*16
	ASL	A	;*32
	ROL	TEMPHI	;SHIFT CARRY
;
	CLC		;ADD *8+*32=*40
	ADC	LOX8
	STA	COLLO	;*40 LO
	LDA	TEMPHI
	ADC	#0
	STA	COLHI	;*40 HI
;
	CLC		;GET FINAL COLLISION ADDR
	LDA	#DMEM&$FF	;SCREEN MEM
	ADC	COLLO	;ADD POSITION
	STA	COLLO	;COLLISION ADDR LO
	LDA	#DMEM/256
	ADC	COLHI
	STA	COLHI	;COLLISION ADDR HI
;
	TXA		;GET X
	TAY		;Y=INDEX FOR X POS
	RTS
;
;
;
;SCORE AND LEVEL DISPLAY
;
DISPSCO	SED		;BCD ADDITION
	CLC
	LDX	#2	;DO 3 BYTES
TOTAL	LDA	SCORE,X	;GET OLD SCORE
	ADC	SCOADD,X	;ADD TO SCORE
	STA	SCORE,X	;SAVE SCORE
	DEX
	BPL	TOTAL
	CLD
;
	LDX	#2	;CLEAR SCOADD
	LDA	#0
ZERO	STA	SCOADD,X
	DEX
	BPL	ZERO
;
	LDX	#6	;POSITION 6
	LDY	#0
SCODP	LDA	SCORE,Y	;GET BYTE
	JSR	DISP	;DISPLAY IT
	INX		;NEXT POSITION
	INX
	INY		;NEXT BYTE
	CPY	#3	;DO 3 BYTES
	BNE	SCODP
;
DISPLVL	LDX	#17	;POSITION 17
	LDA	LEVEL	;LEVEL
	JSR	DISP	;DISPLAY IT
;
	RTS
;
;
DISP	STA	DIGIT	;BCD # TO SHOW
	AND	#$0F	;LOWER NIBBLE
	ORA	#$10	;COLOR0
;
	STA	SCOMEM+1,X	;DISLPAY IT
	LDA	DIGIT	;GET BCD #
	LSR	A	;GET HIGH NIBBLE
	LSR	A
	LSR	A
	LSR	A
	ORA	#$10	;COLOR0
	STA	SCOMEM,X	;DISPLAY IT
	RTS
;
;
;
;DISPLAY REMAINING LIVES
;
DISPLIV	LDA	#PMB/256+5	;PLAYER 1 Y POS.
	STA	VP1HI
	LDA	#38
	STA	VP1LO
;
	LDX	#3	;REMOVE ALL
	LDA	#0	;FROM SCREEN
LD1	STA	HPOSP0,X
	DEX
	BNE	LD1
;
	LDA	#26	;COLORS
	STA	PCOLR0+1
	STA	PCOLR0+2
	STA	PCOLR0+3
;
	LDX	#2	;DO 3 PLAYERS
LD2	LDY	#13
LD3	LDA	P0DATA,Y	;SHAPE DATA
	STA	(VP1LO),Y	;SHOW IT
	DEY
	BPL	LD3
	INC	VP1HI	;NEXT PLAYER
	DEX
	BPL	LD2
;
	LDX	LIVES
	DEX		;SHOW ONE LESS
	BEQ	LD5	;NONE TO SHOW
LD4	LDA	TABX,X	;POSITIONS
	STA	HPOSP0,X	;SHOW PLAYERS
	DEX
	BNE	LD4
LD5	RTS
;
TABX	.BYTE	0,176,183,190
;
;
;
;DISPLAY LIST INTERRUPT
;
DLI	PHA		;SAVE X,Y,A
	TXA
	PHA
	TYA
	PHA
;
	LDX	DLCNT	;WHICH LINE
	LDA	BODYCLR,X	;COLOR0
	LDY	SPOTCLR,X	;COLOR1
	STA	WSYNC	;WAIT FOR SYNC
	STA	COLPF0	;CHANGE HARDWARE REG
	STY	COLPF0+1
	INC	DLCNT	;NEXT LINE
	CPX	#11	;LAST ONE?
	BNE	DLIEND	;NO
	LDX	#0	;YES
	STX	DLCNT	;RESET TO TOP
;
DLIEND	PLA		;RESTORE X,Y,A
	TAY
	PLA
	TAX
	PLA
	RTI
;
BODYCLR	.BYTE	134,198,24,86,126,182,70,42,6,102,14
;
SPOTCLR	.BYTE	14,26,60,28,136,202,122,70,28,60,168
;
;
;
;
;CLEAR P/M MEMORY
;
CLRPM	LDA	#0	;MISSILE BASE
	STA	VPM0LO
;
	LDX	#5	;DO 5 PAGES UP
	LDA	#0
	TAY
CPM	STA	(VPM0LO),Y	;CLEAR IT
	DEY
	BNE	CPM
	INC	VPM0HI	;NEXT PAGE
	DEX
	BNE	CPM
;
	LDA	#PMB/256+3	;RESET
	STA	VPM0HI
;
	LDX	#3	;UPDATE TO SHOW
	LDA	#0	;ALL MISSILES OFF
OFF	STA	SPKFLG,X
	STA	MSTOP,X
	STA	MSTAT
	DEX
	BPL	OFF
;
	RTS
;
;
;
;START PLAYER
;
STARTP0	LDA	#128	;Y START POS.
	STA	VP0LO
	LDA	#100	;X
	STA	HPOSP0
	STA	SHP0
;
	LDA	#14
	STA	PCOLR0	;COLOR P0
;
	LDY	#13
DISP0	LDA	P0DATA,Y	;SHAPE DATA
	STA	(VP0LO),Y	;SHOW IT
	DEY
	BPL	DISP0
;
	RTS
;
;
;
;CLEAR SCREEN MEMORY
;
CLRSM	LDX	#1	;2 PAGES
	LDA	#0
	TAY
CSM	STA	(DMLO),Y	;CLEAR IT
	DEY
	BNE	CSM
	INC	DMHI	;NEXT PAGE
	DEX
	BPL	CSM
;
	LDA	#DMEM/256	;RESTORE
	STA	DMHI
;
	RTS
;
;
;
;PLAYFIELD SETUP
;
SETUP	JSR	RNDPF	;PUT ON BUGS
	INC	DMHI	;NEXT PAGE OF MEMORY
	JSR	RNDPF	;MORE BUGS
	DEC	DMHI	;RESTORE
;
	CLC
	LDA	DMLO	;FIND ADDR
	ADC	#160	;SCREEN CENTER
	STA	DMLO
	LDA	DMHI
	ADC	#0
	STA	DMHI
;
	LDY	#160	;CLEAR 4 LINES
	LDA	#0	;IN SCREEN CENTER
CP0S	STA	(DMLO),Y	;FOR START
	DEY
	BNE	CP0S
;
	LDA	#DMEM&$FF	;RESTORE
	STA	DMLO
	LDA	#DMEM/256
	STA	DMHI
	RTS
;
;
RNDPF	LDX	LEVHEX	;INDEX
	LDA	BUGLEV,X	;# TO DISPLAY
	STA	BUGCNT
;
SET1	LDY	RANDOM	;POSITION
	JSR	BUG	;SHOW THEM
	DEC	BUGCNT	;ANY MORE?
	BPL	SET1	;YES
	RTS		;NO
;
BUG	LDX	#4	;CHARACTERS 1-4
SBUG	TXA
	STA	(DMLO),Y	;SHOW BUGS
	DEY
	DEX
	BNE	SBUG
;
	RTS
;
BUGLEV	.BYTE	0,6,10,15,25,16,10
	.BYTE	20,22,25,25,27,30,30,35,35
;
;
;
;CHECK IF LEVEL COMPLETE
;
CKLEV	LDX	#1	;2 PAGES
	LDY	#0
CKL1	LDA	(DMLO),Y	;GET MEMORY
	BNE	NOTDONE	; IF<>0 NOT DONE
	DEY		;CHECK NEXT
	BNE	CKL1
	INC	DMHI	;NEXT PAGE
	DEX
	BPL	CKL1
;
	LDX	#1	;ALL ZERO,LEVEL DONE
	STX	LVLFLG	;SET FLAG
	BNE	LVLDONE
;
NOTDONE	LDX	#0	;NOT DONE
	STX	LVLFLG
LVLDONE	LDA	#DMEM/256	;RESET
	STA	DMHI
;
	RTS
;
;
;
;
;
; VBLANK ROUTINE
;
;
VBLANK	CLD
;
	LDX	TIMER	;COUNT DOWN TIMER
	BEQ	SOUND1
	DEC	TIMER
;
SOUND1	LDX	M0SND	;MISSILE SOUND ON?
	BEQ	NOSND1	;NO
	LDA	M0SND1,X	;YES, NEXT FREQ
	STA	AUDF1
	DEC	M0SND
	BNE	SOUND2
NOSND1	LDA	#0	;OFF
	STA	AUDC1
;
SOUND2	LDX	HITSND	;BUG HIT SND ON?
	BEQ	NOSND2	;NO
	LDA	HITSND2,X	;YES, NEXT FREQ
	STA	AUDF2
	DEC	HITSND
	BNE	SOUND3
NOSND2	LDA	#0	;OFF
	STA	AUDC2
;
SOUND3	LDA	P0SND	;BLOW UP SND ON?
	BEQ	NOSND3	;NO
	LSR	A	;YES,/2
	STA	AUDC3
	DEC	P0SND
	BNE	SOUND4
NOSND3	LDA	#0	;OFF
	STA	AUDC3
;
SOUND4	LDX	LVLSND	;SOUND 4 ON?
	BEQ	NOSND4	;NO
	DEC	LVLSND	;YES
	BNE	STOPVB
NOSND4	LDA	#$00	;OFF
	STA	AUDC4
;
STOPVB	LDA	STOP	;CONTINUE?
	BNE	COLCK	;YES
EXIT	JMP	XITVBV	;NO
;
COLCK	LDA	P0PF	;PLAYER HIT?
	BEQ	MOVE	;NO
	INC	P0DEAD	;YES,SET FLAG
	JMP	EXIT
;
MOVE	LDX	SHP0	;PLAYER X POS
	LDY	VP0LO	;Y POS
;
	LDA	STICK0
	LSR	A	;CHECK D0
	BCS	NOTUP	;SET,NO MOTION
	DEY		;NOT SET,MOVE UP 2
	DEY
;
NOTUP	LSR	A	;CHECK D1
	BCS	NOTDOWN	;NO
	INY		;MOVE DOWN 2
	INY
;
NOTDOWN	LSR	A	;CHECK D2
	BCS	NOTLEFT	;NO
	DEX		;MOVE 2 LEFT
	DEX
;
NOTLEFT	LSR	A	;CHECK D3
	BCS	NOTRT	;NO
	INX		;MOVE 2 RIGHT
	INX
;
NOTRT	CPX	#50	;LEFT LIMIT
	BCC	BADX	;TOO FAR
	CPX	#208	;RIGHT LIMIT
	BCC	GOODX	;OK? YES
	LDX	#50	;NO,RESET TO LEFT
GOODX	STX	SHP0	;NEW X POS
	STX	HPOSP0
;
BADX	CPY	#90	;UPPER LIMIT
	BCC	BADY	;TOO FAR? YES
	CPY	#185	;LOWER LIMIT
	BCS	BADY	;TOO FAR? YES
	STY	VP0LO	;OK, SAVE IT
;
BADY	LDY	#13	;READ IN PLAYER
LP1	LDA	P0DATA,Y	;AT VP0LO
	STA	(VP0LO),Y
	DEY
	BPL	LP1
;
	LDA	#0	;STOP ATTRACT
	STA	ATRACT
	JMP	EXIT	;ALL DONE
;
;
;
;DATA TABLES
;
P0DATA
	.BYTE	0,0,8,8,8,28,28,62,62,62,62,62,0,0
;
EXPLODE
	.BYTE	8,16,74,34,72,68,16,133,16
	.BYTE	4,162,20,69,18,72,18,8,16
;
M0SND1
	.BYTE	230,240,250,255,230,200,180,170,150,130
	.BYTE	100,75,65,50,45,40
;
HITSND2
	.BYTE	120,100,90,80,75,70,50,40,30,20,10,5
;
MESSAGE
	.BYTE	167,161,173,165,0,175,182,165,178
;
CHR1	.BYTE	0,0,0,0,0,0,0,0
	.BYTE	0,12,51,86,90,86,51,12
	.BYTE	0,204,51,149,165,149,51,204
	.BYTE	0,204,51,86,90,86,51,204
	.BYTE	0,192,48,148,165,148,48,192
;
SCOLN
	.BYTE	$73,$63,$6F,$72,$65,0,0,0,0,0,0,0,0
	.BYTE	$6C,$76,$6C,0,0,0
	*=	*+21
;
	.END