freepascal.compiler/docs/mathex/ex22.pp

Program Example22;

{ Program to demonstrate the log2 function. }

Uses math;

begin
  Writeln(Log2(2):8:4);
  Writeln(Log2(4):8:4);
  Writeln(Log2(8):8:4);
  Writeln(Log2(1):8:4);
  Writeln(Log2(0.5):8:4);
  Writeln(Log2(0.25):8:4);
  Writeln(Log2(0.125):8:4);
end.