汇编程序18：利用and和or指令变换大小写

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,0
          mov cx,5
        s:
          mov al,[bx]
          and al,11011111B
          mov [bx],al
          inc bx
          loop s
          mov bx,5
          mov cx,11
       s0:
          mov al,[bx]
          or al,00100000B
          mov [bx],al
          inc bx
          loop s0
    mov ax,4c00h
    int 21h
code ends

end start