fsqrt

[David Laight]

> > +
> > +static double crackpot_sqrt(double val)
> > +{
> > +    int i;
> > +    float x, y;
> > +    const float f = 1.5F;
> > +
> > +    x = val * 0.5F;
> > +    y  = val;
> > +    i  = * ( int * ) &y;
> > +    i  = 0x5f3759df - ( i >> 1 );
> > +    y  = * ( float * ) &i;
> > +    y  = y * ( f - ( x * y * y ) );
> > +    y  = y * ( f - ( x * y * y ) );
> > +    return val * y;
> > +}
> > +
> 
> For those interested, this is the Quake3 sqrt from Carmack ... there's
> plenty of literature about it one or two google clicks away :-)

I guess that is a rough enough approximation for graphics.

However it will be miscompiled unless i and y are put in a union.

	David