I need help with inline assembly for visual studio

[zodiacbrave]

So, I want to do these operations using inline assembly. I'm using visual studio 2008 and I'm getting weird results towards the end. I think it has to do with the fpu register stack. norm2 comes out as garbage values, while c, b and a are what they are supposed to be. Anyway, this is my c code and my asm is beneath it.

double a = 1.0, b = 2.0, norm2 = 0.0, two = 2.0, x = 3.0, y = 4.0, c;
    c = a*a - b*b + x;
    b = 2.0*a*b + y;
    a = c;
    norm2 = a*a + b*b;

__asm 
  {
    fld b ; st: b
    fmul st(0), st(0) ; st: b * b
    fld a ; st: a, b * b
    fmul st(0), st(0) ; st: a * a, b * b
    fsub st(0), st(1) ; st: a * a - b * b, b * b
    fld x ; st: x, a * a - b * b, b * b
    fadd st(0), st(1) ;  st: x + a * a - b * b,a * a - b * b, b * b
    fstp c  ; our new c  st: a * a - b * b, b * b

  
    fld b ; st: b
    fld a ; st: a, b
    fmul st(0), st(1) ; a * b, b
    fld two ; 2, a * b, b
    fmul st(0), st(1) ; a * b * 2, a * b, b
    fld y ; y, a * b * 2, a * b, b
    fadd st(0), st(1)
    fstp b


    fld c
    fst a

    fmul st(0), st(0)
    fld b
    fmul st(0), st(0)
    fadd st(0), st(1)
    fstp norm2
  }

Is it important to pop the stack? Does that slow down the program?

Thank you