1 PMBASE=54279:REM Player-missile base pointer
2 RAMTOP=106:REM OS top of RAM pointer
3 SDMCTL=559:REM RAM shadow of DMACTL register
4 GRACTL=53277:REM CTIA graphics control register
5 HPOSP0=53248:REM Horizontal position of P0
6 PCOLR0=704:REM Shadow of player 0 color
10 GRAPHICS 0:SETCOLOR 2,0,0:REM Set background color to black
20 X=100:REM BASIC's player horizontal position
30 Y=48:REM BASIC's player vertical position
40 A=PEEK(RAMTOP)-8:REM Get RAM 2K below top of RAM
50 POKE PMBASE,A:REM Tell ANTIC where PM RAM is
60 MYPMBASE=256*A:REM Keep track of PM RAM address
70 POKE SDMCTL,46:REM Enable PM DMA with 2-line res
80 POKE GRACTL,3:REM Enable PM display
90 POKE HPOSP0,100:REM Declare horizontal position
100 FOR I=MYPMBASE+512 TO MYPMBASE+640:REM this loop clears player
110 POKE I,0
120 NEXT I
130 FOR I=MYPMBASE+512+Y TO MYPMBASE+518+Y
140 READ A:REM This loop draws the player
150 POKE I,A
160 NEXT I
170 DATA 8,17,35,255,32,16,8
180 POKE PCOLR0,88:REM Make the player pink
190 A=STICK(0):REM Read joystick
200 IF A=15 THEN GOTO 190:REM If inactive, try again
210 IF A=11 THEN X=X-1:POKE HPOSP0,X
220 IF A=7 THEN X=X+1:POKE HPOSP0,X
230 IF A<>13 THEN GOTO 280
240 FOR I=8 TO 0 STEP -1
250 POKE MYPMBASE+512+Y+I,PEEK(MYPMBASE+511+Y+I)
260 NEXT I
270 Y=Y+1
280 IF A<>14 THEN GOTO 190
290 FOR I=0 TO 8
300 POKE MYPMBASE+511+Y+I,PEEK(MYPMBASE+512+Y+I)
310 NEXT I
320 Y=Y-1
330 GOTO 190