PowerFnc

Function IntPower(X: Real; I: LongInt): Real;
Var
    Y: LongInt;
    Res: Real;
Begin
    Y:= Abs(I);
    Res:= 1.0;
    While Y > 0 Do Begin
        While Not Odd(Y) Do Begin
            Y:= Y Shr 1;
            X:= X * X
        End;
        Dec(Y);
        Res:= Res * X;
    End;
    If I < 0 Then Res:= 1.0 / Res;
    IntPower:= Res;
End;


Function Power(B, E: Real): Real;
Begin
    If E = 0.0 Then
        Power:= 1.0
    Else If (B = 0.0) And (E > 0.0) Then
        Power:= 0.0
    Else If (Frac(E) = 0.0) And (Abs(E) <= MaxLongInt) Then
        Power:= IntPower(B, LongInt(Trunc(E)))
    Else
        Power:= Exp(E * Ln(B));
End;