汇编语言problem

Error A2062:missing or unreachable cs

代码段要和cs关联

//assume cs:data,ds:code is error
assume cs:code,ds:data

data segment
      db 'DEC'
      db 'Ken Olsen'
      dw 127
      dw 40
      db 'PDP'
data ends
code segment
 start: mov ax,data
     mov ds,ax
     mov di,0CH
     mov bx,38
     mov [di],bx
     
     mov ax,4c00h
     int 21h
     
code ends
end start