DATA1 DB +96
  DATA2 DB +70
  RESULT DW ?
  ......
  SUB AH,AH 
  MOV AL,DATA1 
  MOV BL,DATA2 
  ADD AL,BL 
  JNO OVER 
  MOV AL,DATA2 
  CBW 
  MOV BX,AX 
  MOV AL,DATA1 
  CBW 
  ADD AX,BX 
OVER: MOV RESULT,AX