一段汇编程序

assume cs:code,ds:data,ss:stack;关联各段

data segment
        db 'ibm             '；定义数据
        db 'dec             '
        db 'com             '
data ends

stack segment
        dw 0,0,0,0,0,0,0,0,0,0,0;堆栈段
stack ends
code segment
        start:
                mov ax,data
                mov ds,ax;真正关联数据段

                mov ax,stack;关联堆栈段
                mov ss,ax
                mov sp,10h

                mov bx,0
                mov cx,3

                s:
                    push cx;双层循环，保存外层循环的cx
                        mov cx,3
                        mov si,0
                        s1:
                                mov al,ds:[bx+si]
                                and al,11011111b;变成大写
                                mov ds:[bx+si],al
                                inc si
                        loop s1
                    pop cx
                    add bx,16
                loop s

                mov ax,4c00h
                int 21h
code ends

end start