Half-float to single precision floating point conversion routine

union U {
    int i;
    float f;
};


float h2f(unsigned short y)
{

    if (BigEndian)
    y=ToLittleEndian(y);

    U value;

    int s = (y >> 15) & 0x00000001;
    int e = (y >> 10) & 0x0000001f;
    int m =  y        & 0x000003ff;

    if (e == 0)
    {
    if (m == 0)
    {
        //
        // Plus or minus zero
        //

        return s << 31;
    }
    else
    {
        //
        // Denormalized number -- renormalize it
        //

        while (!(m & 0x00000400))
        {
        m <<= 1;
        e -=  1;
        }

        e += 1;
        m &= ~0x00000400;
    }
    }
    else if (e == 31)
    {
    if (m == 0)
    {
        //
        // Positive or negative infinity
        //

        return (s << 31) | 0x7f800000;
    }
    else
    {
        //
        // Nan -- preserve sign and significand bits
        //

        return (s << 31) | 0x7f800000 | (m << 13);
    }
    }

    //
    // Normalized number
    //

    e = e + (127 - 15);
    m = m << 13;

    //
    // Assemble s, e and m.
    //

    value.i = (s << 31) | (e << 23) | m;
    return value.f;

}