floating point unit programming problem

[Silvercord]

I'm bored, no school today, so I'm learning how to do assembly with the floating point unit instruction set. I'm trying to normalize a vector, but I cannot access the vector's x,y,or z components, instead i've got to copy to a local variable. Any way around doing that? Here's the code (with comments)

void	Vector3::Normalize()
{
#if	1

	float	basic = x*x + y*y + z*z;
		_asm
		{
			FLD	basic; //Put basic length into st(0)
			FSQRT;		//Put SQUARE ROOT of basic into st(0)
			FSTP basic; //Store square root of basic into memory address of basic, pop stack
		}
		if(basic>.0001) //won't ever be exactly zero
		{
			//Can't seem to access this->x,y,or z
			float	x1 = x;
			float	y1 = y;
			float	z1 = z;
			_asm
			{
				FLD	x1;			//Load into FPU stack element zero
				FDIV	basic;	//divide by length
				FSTP	x1;		//store in x1 and pop stack 

				FLD	y1;
				FDIV	basic;
				FSTP	y1;

				FLD z1;
				FDIV	basic;
				FSTP	z1;
			}
			x =	x1;
			y = y1;
			z = z1;
		}
#else
	float	magnitude = sqrt( (x * x) + (y * y) + (z * z) );
	if(magnitude)
	{
		x /= magnitude;
		y /= magnitude;
		z /= magnitude;
	}
#endif
}