汇编语言 第三版 王爽 实验6 更改大写字母

assume cs:code,ds:data,ss:stack
data segment
db '1. display      '
db '2. brows        '
db '3. replace      '
db '4. modify       '
data ends
code segment

stack segment
dw 0,0,0,0,0,0,0,0
stack ends

start:
	mov ax,data
	mov ds,ax
	mov bx,0
	
	mov ax,stack
	mov ss,ax
	mov sp,16

	mov cx,4
	s:push cx

	 mov si,0
	 mov cx,4
	 s1:
	  mov al,[bx+3+si]
	  and al,11011111b
	  mov [bx+3+si],al
	  inc si
	 loop s1
	 
	add bx,16
	pop cx
	loop s
	
	mov ax,4c00h
	int 21h
code ends
end start