static void vlength(void)
{
	float a = fifoin_pop_f() - tgp_vr_base[0];
	float b = fifoin_pop_f() - tgp_vr_base[1];
	float c = fifoin_pop_f() - tgp_vr_base[2];

	a = (a*a+b*b+c*c);
	b = sqrt(a); 
	c = b - tgp_vr_base[3];

	fifoout_push_f(c); 
	next_fn();
}