$O = 19, $C = ~$C& 0x4D; # bits 7+ all 0
$O = 20, $C = ~$C| 0x20; # bits 7+ all 1
$O = 21, $C = ~$C^ 0x70; # bits 7+ all 0 bits 6543210
$O = 22, $C =  $C&~0x6F; # bits 7+ all 0      00?0000
$O = 23, $C = ~$C| 0x73; # bits 7+ all 1      1111111
$O = 24, $C =  $C^~0x74; # bits 7+ all 0      1110100