gistfile1.c

/*
** float q_rsqrt( float number )
*/
float Q_rsqrt( float number )
{
	floatint_t t;
	float x2, y;
	const float threehalfs = 1.5F;

	x2 = number * 0.5F;
	t.f  = number;
	t.i  = 0x5f3759df - ( t.i >> 1 );               // what the fuck?
	y  = t.f;
	y  = y * ( threehalfs - ( x2 * y * y ) );   // 1st iteration
//	y  = y * ( threehalfs - ( x2 * y * y ) );   // 2nd iteration, this can be removed

	return y;
}

float Q_fabs( float f ) {
	floatint_t fi;
	fi.f = f;
	fi.i &= 0x7FFFFFFF;
	return fi.f;
}