assume cs:code,ds:data

 //and指令使某位变0,or指令使某位变1

 data segment

     db 'BaSic','iNfOrMaTiOn' //db指令:定义字节数据,与dw指令:定义字数据

 data ends

 code segment

     start:

           mov ax,data

           mov ds,ax

           mov bx,

           mov cx,

         s:

           mov al,[bx]

           and al,11011111B

           mov [bx],al

           inc bx

           loop s

           mov bx,

           mov cx,

        s0:

           mov al,[bx]

           or al,00100000B

           mov [bx],al

           inc bx

           loop s0

     mov ax,4c00h

     int 21h

 code ends

 end start