sound0.asm

在提示符后从键盘上输入I（或i）进入到频率变化率输入

DATAS SEGMENT para 'data' 
freq  dw  300
chnrate label byte
max  db 4
act  db ?
acchnrate db 4 dup (?)
msg1       db  'press I to input the change rate;press Q to quit:',13,10,'$'
msg2       db  'please input the rate of change:',13,10,'$'
errormsg   db  'Wrong instruction  ,please input again!',13,10,'$'
DATAS ENDS
STACKS SEGMENT  stack para  'stack'
                db 64 dup('stack...')
STACKS ENDS

CODES SEGMENT
main proc far
   ASSUME CS:CODES,DS:DATAS,SS:STACKS
   MOV    AX,DATAS
   MOV    DS,AX

repeat:
   mov   ah,09h
   lea   dx,msg1
   int   21h   
   mov   ah,08
   int   21h
   
   cmp   al,'q'
   jz   exit
   cmp   al,'Q'
   jz   exit
   cmp   al, 'i'
   jz    product
   cmp   al,'I'
   jz    product
   
   lea   dx,errormsg
   mov   ah,09h
   int   21h
   jmp   repeat
product:
   mov   ah,09h
   lea   dx,msg2
   int   21h
     
   
   mov   ah,10
   lea   dx,chnrate    
   int   21h
   mov   ah,2
   mov   dl,13
   int   21h
   mov   dl,10
   int   21h
                       ;得到输入的变化率
   sub   ax,ax
   sub   cx,cx
   sub   bx,bx
   mov   cl,act
 
   mov   dl,10
   lea   si,acchnrate 
convert:
   mov   al,[si]
   sub   al,30h
   push  cx
   dec   cx 
   and   cx,cx
   jz    add1
multiply:
   mul   dl
   loop  multiply
add1: 
   pop   cx
   add   bx,ax
   inc   si
   loop  convert
   mov   ax,bx
      
   lea   si,freq
   mov   bx,20
callproc:    
   call  changefre  
   jmp   repeat
exit:  
   mov   ax,4c00h
   int   21h
main endp

changefre  proc  near
   mov di,[si]
   add ax,di

next :
    call sound
    inc  di
    cmp  di,ax
    jne  next
    ret
changefre  endp

sound proc near
      push di
      push ax
      push dx
      push bx    
      mov  al,0b6h    
      out  43h,al      ;初始化43端口
      mov  dx,12h
      mov  ax,348ch    ;系统固有频率
      div  di
      out  42h,al
      mov  al,ah
      out  42h,al
    
      in   al,61h
      mov  ah,al
      or   al,3         ;打开蜂鸣器
      out  61h,al
lenth:                  ;延时10ms
      mov  cx,633

waitf:
      in   al,61h        ;测试 第 4位是否 为 1  得到 15.6 ns的 延时 
      and  al,10h
      jz   waitf
      loop waitf
      dec  bx 
      jne  lenth
      mov  al,ah
      and  al,0fch
      out  61h,al
      
      pop  bx                                 
      pop  dx
      pop  ax
      pop  di
      ret
 
sound endp
  CODES ENDS
    END main