code:

float Q_rsqrt( float number )

{

	long i;

	float x2, y;

	const float threehalfs = 1.5F;


	x2 = number * 0.5F;

	y = number;

	i = * ( long * ) &y;						// evil floating point bit level hacking

	i = 0x5f3759df - ( i >> 1 ); // what the gently caress?

	y = * ( float * ) &i;

	y = y * ( threehalfs - ( x2 * y * y ) ); // 1st iteration

//	y = y * ( threehalfs - ( x2 * y * y ) ); // 2nd iteration, this can be removed


#ifndef Q3_VM

#ifdef __linux__

	assert( !isnan(y) ); // bk010122 - FPE?

#endif

#endif

	return y;

}