QNAN bei Floatmultiplikation auf 8051F und Keil

float iir(float NewSample) {

    idata float ACoef[NCoef+1] = {

        0.00000000000024335396,

        0.00000000000194683167,

        0.00000000000681391085,

        0.00000000001362782170,

        0.00000000001703477712,

        0.00000000001362782170,

        0.00000000000681391085,

        0.00000000000194683167,

        0.00000000000024335396

    };

    idata float BCoef[NCoef+1] = {

        1.00000000000000000000,

        -7.70663582543307600000,

        25.98811769708422400000,

        -50.08564889641004900000,

        60.33895663605833400000,

        -46.52942830250031400000,

        22.42862119389475600000,

        -6.17879494249887260000,

        0.74481243984022838000

    };

    static float y[NCoef+1]; //output samples

    static float x[NCoef+1]; //input samples

    int n;

  idata float test;

    //shift the old samples

    for(n=NCoef; n>0; n--) {

       x[n] = x[n-1];

       y[n] = y[n-1];

    }

    //Calculate the new output

    x[0] = NewSample;

    y[0] = ((ACoef[0]) * (x[0]));

    for(n=1; n<=NCoef; n++)

        y[0] += ACoef[n] * x[n] - BCoef[n] * y[n];

    return y[0];

}