实验11代码

三田学校

代码如下：

assume cs:code,ds:data

data segment
db "Beginner's All-purpose Symbolic Instruction Code.",0
data ends

code segment
start:
mov ax,data
mov ds,ax

mov ax,0b878h
mov es,ax

mov si,0
mov di,0

call letterc
mov ax,4c00h
int 21h
letterc:
mov al,[si]
cmp al,0
je exit
cmp al,'a'
jb s0
cmp al,'z'
ja s0
and al,11011111b
mov byte ptr [si],al
s0:
;显示白底黑字
mov byte ptr es:[di],al
mov byte ptr es:1[di],01110000b
inc si
add di,2
jmp short letterc
exit:
ret
code ends
end start