《汇编语言》 第七章 实验六

要求 将每个单词前四个字母转为大写

assume cs:codesg,ss:stacksg,ds:datasg
stacksg segment
  dw 0,0,0,0,0,0,0,0
stacksg ends
datasg segment
 db '1. display      '
 db '2. brwos        '
 db '3. replace      '
 db '4. modify       '
datasg ends
codesg segment
 start:
   mov ax,stacksg
   mov sp,16
   mov ax,datasg
   mov ds,ax
   mov bx,0
   mov cx,4
 s0:
   push cx
   mov si,3
   mov cx,4
 s:
   mov al,[bx+si]
   and al,11011111B
   mov [bx+si],al
   inc si
   loop s

   add bx,16
   pop cx
   loop s0

   mov ax,4c00h
   int 21h
codesg ends
end start