data segment

freq dw 196,220

dw 262,262,262,262,262,220,196

dw 262,262,262,262,294,262,220,262

dw 294,294,294,294,294,262,220

dw 294,294,294,294,330,294,330,392

dw 440,440,392,440,392,330

dw 294,294,330,294,262,220,196,220

dw 262,262,262,262,262,220

dw 262,196,220

dw 440,440,392,440,524,440

dw 392,330,294,262,220,196,220

dw 262,262,262,262,294,262

dw 262,330,392

dw 440,440,440,440,524,440

dw 392,392,392,440,392,330,294

dw 262,262,262,262,294

dw 330,330,294

dw 262,262,262,262,524,440

dw 392,392,392,440,392,330,392

dw 440,524,524,440,392

dw 392,330,392

dw 440,440,440,440,524,440

dw 392,392,392,440,392,330,294

dw 262,262,262,262,392

dw 330,330,294

dw 262,262,262,262,294,330

dw 392,392,330,392,330,392

dw 440

dw 19,19,196,660,294,294,262

dw 262,-1

time dw 400,400

dw 400,200,400,400,800,400,400

dw 400,200,400,200,200,800,400,400

dw 400,200,400,400,800,400,400

dw 400,200,400,200,200,800,400,400

dw 400,800,400,800,400,400

dw 400,200,200,400,400,800,400,400

dw 400,200,400,400,800,800

dw 1600,800,800

dw 400,800,400,800,400,400

dw 400,400,400,400,800,400,400

dw 400,800,400,800,400,200

dw 2400,400,400

dw 400,800,400,800,400,400

dw 400,800,200,200,800,400,400

dw 400,800,400,800,800

dw 2400,400,400

dw 400,800,400,800,400,400

dw 400,800,200,200,800,400,400

dw 800,400,800,400,200

dw 2400,400,400

dw 400,800,400,800,400,400

dw 400,800,200,200,800,400,400

dw 400,800,400,800,800

dw 2400,400,400

dw 400,800,400,800,400,400

dw 400,800,400,800,400,400

dw 3200

dw 800,400,400,400,400,400,400

dw 4000

data ends

code segment

assume cs:code,ds:data

start:

mov ax,data

mov ds,ax ;初始化数据段寄存器

lea si,freq ;把freq在数据段的偏移存入si

lea di,time ;把time在数据段的偏移存入di

l1:

mov cx,[si]

cmp cx,-1

je exit ;如果初始化失败，就像看到的一样，cx的值是负一那么就退出了

mov bx,[di]

call gensound

add si,2

add di,2

jmp l1 ;每次从time中取一个字，然后调用gensound

exit:

mov ax,4c00h

int 21h

;bx(放延时计数值)、cx(放频率计数值)为入口参数。

gensound proc near

push dx

MOV AL,0B6H ;位组合格式：通道2，两字节计数，模式3，二进制编码, 得到控制字；

OUT 43H,AL ;将控制字数送43H端口（方式寄存器）

mov dx,12h

mov ax,3280h

div cx ;计算123280h/cx--->dx,ax

out 42h,al ;把商的低字节（频率计数值）写入42h端口（定时器通道2）

mov al,ah

out 42h,al ;再把商的高字节写入到42h端口

in al,61h

mov ah,al

or al,3 ;控制音长的时间可以简单地通过反复执行循环指令来得到

out 61h,al

;接通扬声器

push ax

l2:

mov dx,8h ;送基准延时值

mov ax,0f05h

s1:

sub ax,1

sbb dx,0 ;DX:AX减去了1（sbb指令是带借位减法指令:(dx)=(dx)-0-CF）

jnz s1 ;kill time

dec bx ;这是第一次使用bx,也就是传入参数。

jnz l2 ;kill time

pop ax

mov al,ah ;果然是保护AH的值的

out 61h,al ;恢复扬声器原来的设置

pop dx

ret

gensound endp

code ends

end start