Shl
From Free Pascal wiki
Template:shl
Shift left (shl) performs a left bit-shift operation (opposite than shr).
E.g
Command is: 00000100 shl 2 Action is: 00000100 <- 00 Result is: 00010000
Clear a bit
function ClearBit( const aValue, aBitNumber : integer ) : integer;
begin
result := aValue and not( 1 shl aBitNumber );
end;
If you call ClearBit(%1111,1) then get %1101 (%1111 = 15 and %1101 = 13). If you call ClearBit(13,2) then get 9 (9 = %1001) .