10 REM COPYRIGHT 1987 COMPUTE! PUBLICATIONS INC. - ALL RIGHTS RESERVED
20 IFPEEK(49179)<>56THENLOAD"SCROLL.ML",8,1
30 SYS49873:POKE53280,11:POKE53281,0:PRINT"[147]"
40 PRINT"   COPYRIGHT 1987 COMPUTE! PUB., INC."
50 PRINTTAB(10)"ALL RIGHTS RESERVED[150]"
60 PRINT"           ...PLEASE WAIT..."
70 GOSUB480
80 GOSUB320
90 PRINT"[145]INTRODUCING THE IMPOSSIBLE SCROLL"
100 PRINT"PROGRAM. JUST WATCH THE SCROLLING"
110 PRINT"MESSAGE AT THE BOTTOM. NOTE HOW IT"
120 PRINT"IS BELOW THE NORMAL DATA AREA, AWAY"
130 PRINT"FROM INTERFERING WITH A TEXT DISPLAY."
140 GOSUB430
150 SYS49152
160 GETA$
170 PRINT"[147][153]THE SCROLLING MESSAGE CAN BE ENLARGED"
180 POKE53271,255
190 PRINT"BY CHANGING THE PROGRAM, OR BY SETTING"
200 PRINT"THE SPRITE Y-EXPANSION."
210 GOSUB430
220 SYS49628:GETA$
230 POKE53271,170
240 PRINT"[154]OR HOW ABOUT 'UP AND DOWN SCROLL'?":SYS49628
250 PRINT"[147][154]   ...OR COLOR CHANGES TO THE SCREEN?"
260 FORA=0TO240:POKE49267,A:NEXT:POKE198,0
270 PRINT"[147][154]    PRESS ANY KEY TO START DEMO OVER"
280 POKE53269,0
290 POKE53280,RND(1)*15:GETA$:ON-(A$="")GOTO290:RUN
300 END
310 REM POKE IN MESSAGE FROM DATA
320 I=7*4096
330 READ X$:IF X$="END" THEN POKE I,0:RETURN
340 FORZ=1TOLEN(X$):G=ASC(MID$(X$,Z,1)):IFG>=64ANDG<=95THENG=G-64:GOTO360
350 IFG>95THENG=INT(G-128)
360 POKEI,G:I=I+1:NEXT:GOTO330
370 REM DATA FOR MESSAGE
380 DATA"THIS IS THE SCROLL PROGRAM WHICH DEFIES THE NORMAL PHYSICS OF THE"
390 DATA" VIC-II CHIP...    BY USING RASTER INTERRUPTS, THE PROGRAM TRICKS "
400 DATA"THE COMPUTER INTO DISPLAYING SPRITES BELOW THE BORDER. THIS "
410 DATA"ENABLES THE USER TO SCROLL MESSAGES IN THE AREA WHERE DATA USUALLY "
420 DATA"DOESN'T BELONG!   ","END"
430 PRINT"";:FORA=1TO40:PRINT"-";:NEXT
440 PRINT"[158]       PRESS ANY KEY TO SEE MORE"
450 FORA=1TO40:PRINT"-";:NEXT:PRINT"":RETURN
460 END
470 REM LOAD A CHARACTER SET
480 RETURN: <-------REM ERASE THIS LINE TO LOAD CUSTOMIZED CHARACTERS
490 POKE49725,96 :REM TURN OFF COPY SUBROUTINE (POKE49725,234 TO RESTORE COPY)
500 POKE184,2:POKE185,0:POKE186,8:REM POKE 186,1 FOR DATASSETTE
510 F$="CHARSET":REM THE NAME OF THE CHARACTER SET
520 POKE183,LEN(F$):POKE187,0:POKE188,2:FORI=1TOLEN(F$)
530 POKE511+I,ASC(MID$(F$,I,1)):NEXT
540 POKE780,0:POKE781,0:POKE782,160:SYS65493
550 RETURN