Adding 64 bits of data tutorial

Question
Show how to add the following two 64 bits of data using 8088/8086 assembly programming . The final answer must be located at CX-DX combination. Then show the final value of CF,PF,ZF,SF and AF flags.

X=4322FFFFh
Y=43210001h

Answer:

     CX DX
+   AX BX
------------
     CX DX
------------

DX+BX can be done using the normal ADD DX,BX. However DX + BX might have a carry result that should be added to the following CX+AX. Therefore to ensure the carry bit (if there is a carry) is added to the following segment ADC (ADD with Carry) must be used.

So the code for this program will be

ADD DX,BX
ADC CX,AX

4322FFFF₁₆=  0100 0011 0010 0010 1111 1111 1111 1111₂
43210001₁₆ =  0100 0011 0010 0001 0000 0000 0000 0001₂


  0100 0011 0010 0010 1111 1111 1111 1111

+0100 0011 0010 0001 0000 0000 0000 0001
-------------------------------------------------
  1000 0110 0100 0100 0000 0000 0000 0000 = 86440000₁₆
-------------------------------------------------

Therefore (check the second set/second command/ADC only)
SF=1 (the sign bit is number 1)
CF=0 (no carry) 
PF=0 (number of 1 is odd)
ZF=0 (result not zero)
AF = 0 (there is carry from bit 3 to bit 4)