[delphi-br] Off Topic Converter função de VB p/ Delphi

[fabio_giro]

Alguém poderia me ajudar a converter esta função?

VB
Public Function binret(s1 As String, i1 As Integer) As Double
   Dim l1 As Double
   Dim i2 As Integer
   Dim i3 As Integer
   l1 = 0
   For i2 = 1 To i1
      i3 = Asc(Mid$(s1, i2, 1))
      l1 = l1 + (i3 * (256 ^ (i1 - i2)))
   Next
   binret = l1
End Function

Delphi
Function binret(s1 : string; i1 : Integer) : Double;
var
   l1 : Double;
   i2 : Integer;
   i3 : Integer;
begin
   l1 := 0;
   For i2 := 1 To i1 do
    begin
      i3 := ord(copy(s1, i2, 1)[1]);
      l1 := l1 + (i3 * (?????));
    end;
   binret := l1;
End;

Agradeço antecipadamente.