10REM Anti VDU 21 15REM (c) 1989 Ben Dooks 20oldvec=!&20E AND &FFFF 30FOR I%=0 TO 3 STEP 3 40P%=&900 50[OPT I% 60.newentry 70CMP #21 80BEQ bad 90CMP #156 100BEQ bad 110JMP ok 120.bad 130LDA #7 140.ok 150JMP oldvec 160]NEXT 170!&20E=!&20E AND &FFFF0000 OR newent ry