;使用8253实现使用1到8弹奏歌曲 ;其他键退出 data segment
message db 'Use 1 ... 8 to play the music','$'
frequ dw 262, 294, 330, 347, 392, 440, 494, 524
data ends
code segment
assume cs:code, ds:data
start:
mov ax, data
mov ds, ax
lea dx, message
mov ah, 09h
int 21h
mov al, 10110110b
out 43h, al ;set the control
next: mov ah, 7
int 21h
cmp al, '1'
jb exit
cmp al, '8'
ja exit
;get the frequency of the number
sub al, 30h
mov ah, 0
mov bx, ax
sub bx, 1
shl bx, 1
mov cx, frequ[bx]
;get the counter
mov ax, 34dch
mov dx, 12h ;DX:AX=1234DCH=1193180D
div cx
mov bx, ax ;set the counter
mov ax, bx
out 42h, al ;send the lower
mov al, ah
out 42h, al ;send th higner
in al, 61h ;set the 0 and 1 as '1'
or al, 03h
out 61h, al
mov cx, 0ffffh
delay: mov dx, 100h
dec_dx: dec dx
jnz dec_dx
loop delay
in al, 61h
and al, 11111100b
out 61h, al ;open the voice
jmp next
exit:
mov ah, 4ch
int 21h
code ends
end start 
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