判断x+y是否溢出

;
; 
;判断x+y是否溢出
; author:  wangguolaing
; date:  revised 4/14


.386
.MODEL FLAT


INCLUDE io.h
includelib Kernel32.lib
ExitProcess PROTO NEAR32 stdcall, dwExitCode:DWORD


cr          EQU    0dh  
Lf          EQU    0ah      


.STACK      4096


.DATA


xnumber  WORD   ?
ynumber  WORD   ?
lable1   BYTE  cr,Lf,Lf,'Overflow',0
lable2   BYTE  cr,Lf,Lf,'No Overflow'


.CODE
_start:
      ;mov xnumber,67000000   ;大测试数据，证明溢出
      ;mov ynumber,870000
      
      mov xnumber,670   ;小测试数据，证明无溢出
      mov ynumber,8700
      




      mov ax,xnumber
	add ax,ynumber
	jo noo
	mov ax,0
	jmp endth
noo:	
      ;mov ax,1  ;产生了溢出
      output lable1
      jmp quit
endth   :
      output lable2
   
quit:       INVOKE ExitProcess, 0   ; exit with return code 0


PUBLIC _start                       ; make entry point public
            END                     ; end of source code