sieve-c64

100 MA=100:MP=20:T1=TIME:DIM NP(MA)
110 FOR I=2 TO 100:NP(I)=0:NEXT
120 D=2
130 IF D*D>MA GOTO 170
140 IF NP(D)=1 GOTO 160
150 FOR I=2*D TO MA STEP D:NP(I)=1:NEXT
160 D=D+1:GOTO 130
170 PRINT "CALCULATION TOOK";TIME-T1;" JIFFY TICKS":PRINT
180 PRINT"PRIMES:";:I=2:C=0 
190 IF NP(I) THEN I=I+1:GOTO 190
200 PRINT I;:I=I+1
210 C=C+1:IF C<MP THEN PRINT",";:GOTO 190

220 PRINT