存储器操作数和立即数在add指令下竟无动于衷的都市怪谈

; 表示楼主的代码用masm 5.00 + DOSBOX编译不通过
assume cs:codesg
assume ds:datasg
assume ss:stacksg
stacksg segment stack
db 100 dup (0)
stacksg ends
datasg segment
db '1997'
datasg ends
codesg segment
start:
mov ax, datasg
mov ds, ax
mov bx, 0
mov ax, 1
add [bx], ax
mov ah, 4CH
int 21H
codesg ends
end start