Shl

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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

<delphi> function ClearBit( const aValue, aBitNumber : integer ) : integer; begin

  result := aValue and not( 1 shl aBitNumber );

end; </delphi>

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) .

See e.g