CODE

proc A () {
	 int x = 0;

	 proc B() {
		  int y = 1;
		  int z = 1;

		  proc C() {
			   int y;
			   y = z;
			   x = z;
			   return;
		  }

		  proc D() {
			   call C();
			   z = x + y;
			   return;
		  }

		  x = 3;
		  call D();
		  return;
	  }

	  proc E() {
		   int y = 3;
		   x = x + 1;
		   x = x + 1;
		   call B();
		   y = 4;
		   return;
	  }

	  x = 5;
	  call E();
	  return;
}

---------------------------------------------------------------------------

STACK FRAME TEMPLATES  (ACTIVATION RECORDS)

   offset   content

A   0       return address
    1       static link
    2       x

B   0       return address
    1       static link
    2       y
    3       z

C   0       return address
    1       static link
    2       y

D   0       return address
    1       static link

E   0       return address
    1       static link
    2       y

---------------------------------------------------------------------------

RESOLVING VARIABLES (STATIC SCOPE)

In procedure        variable 	(static link steps, offset)
      A                x          (0, 2)

      B                x          (1, 2)
                       y          (0, 2)
                       z          (0, 3)

      C                x          (2, 2)
                       y          (0, 2)
                       z          (1, 3)

      D                x          (2, 2)
                       y          (1, 2)
                       z          (1, 3)

      E                x          (1, 2)
                       y          (0, 2)

---------------------------------------------------------------------------

RUN-TIME STACK (FIGURE 3.5) CALL SEQUENCE:A, E, B, D, C

static links		Stack frame

   ----------------     C       <--- top of stack
   |
   |
   |
   |
   | --------------     D
   | |
   | |
   | |
   | ------------->     B
   --------------->		
      ------------- 
      | 
      |
      |
      |     ---------	  E
      |     |
      |     |
      |     |
      |     |
      |     -------->   A
      -------------->