将所有字母转化为大写

;===================
;将所有字母转化为大写
;====================
assume cs:code,ds:data

data segment
    db 'welcome to china'
    db 'dec             '
    db 'dos             '
    db 'vax             '
data ends

code segment
  start:mov ax,data
    mov ds,ax
    mov cx,4
      s:mov si,cx
    mov cx,16
     s0:mov al,[bx]
    and al,11011111b
    mov [bx],al
    inc bx
    loop s0
    mov cx,si
    loop s
    mov ax,4c00h
    int 21h
code ends
end start