汇编简易钢琴

试设计一个程序，能够使用键盘中字母键模拟钢琴按键发音。其中，按照字母在键盘中的排列方式，字母键z/x/c/v/b/n/m分别发出低1—低7共 7个低音音符，字母键a/s/d/f/g/h/j分别发出中1—中7共7个中音音符，字母键q/w/e/r/t/y/u分别发出高1—高7共7个高音音符。按回车键退出程序。

assume CS:code ,DS:data

data segment
              ;A 到Z 26个字母所对应的频率，其中0的只是填充位置，并不计入计算 
   HzInOrder dw 261,196,164,329,659,349,392,440,0,493,0,0,246,220,0,0,523,698,293,783,987,174,587,146,880,130 
   
data ends

code segment
start:
; set segment registers:
   MOV ax, data
   MOV ds, ax          
   
   Lop: 
   MOV AH,8
   INT 21H              ;获取单个字符,隐藏输入    
   MOV AH,0
   MOV si,0 
   
   CMP Al,0DH           ;如果是回车符则退出
   JZ  break    
             
   CALL Judge           ;判断输入是否合法，不合法则跳到循环开始部分
   SUB Al,41H;          将读入数据与大写A对应的ASCII码做减法 
   
   MOV si,ax                            
   MOV AX,SI            ;SI=SI*2
   ADD SI,AX
   
    
   MOV ax,0B6H
   OUT 43H,ax           ;初始化2号定时器   
  
   CALL DIVMOVE         ;除法和输送数据
     
   CALL MUSICON         ;控制扬声器发声     
    
   CALL DELAY           ;控制发声时间
   
   CALL MUSICOFF        ;取消发声
   
   Loop Lop 
   
break:       
   
   MOV ax, 4c00h ; 退出程序
   INT 21h  
     
;------------------------------------------------------------------------
;------------------------------------------------------------------------
;----判断输入是否合法    
Judge proc   
    
   cmp Al,41H   ;  
   jb Lop
   
   cmp Al,5AH   ;
   ja Lop     
   
   cmp Al,49H   ;
   jz Lop       
   
   cmp Al,4FH   ;
   jz Lop       
   
   cmp Al,50H   ;
   jz Lop      
   
   cmp Al,4BH   ;
   jz Lop      
   
   cmp Al,4CH   ;
   jz Lop   
    RET
Judge endp     
 
;------------------------------------------------------------------------
;------------------------------------------------------------------------
;------------------延迟一定时间
 DELAY  PROC
  PUSH CX

  MOV CX,10H;
DELAYLOOP1: 
  PUSH CX;
  
  MOV CX,0FFFFH
DELAYLOOP2:
  LOOP DELAYLOOP2
  
  POP CX;
  LOOP DELAYLOOP1
  
  POP CX
  RET
 DELAY ENDP       
   
;----------------------------------------------------------------------   
;------------------------------------------------------------------------
;-----------------控制发声   
MUSICON PROC   
   
   MOV AL,0       
   IN  AL,61H   
   OR  AL,03H
   OUT 61H,AL                 
   RET 
MUSICON ENDP    

;----------------------------------------------------------------------   
;------------------------------------------------------------------------
;-----------------取消发声   
MUSICOFF PROC   
           
   IN  AL,61H    
   MOV AL,03H
   AND AL,0FCH
   OUT 61H,AL                 
   RET 
MUSICOFF ENDP   

;----------------------------------------------------------------------   
;------------------------------------------------------------------------
;---除法和输送数据
DIVMOVE PROC   
   PUSH AX 
   MOV ax,2870H       
   MOV dx,0012H        
   DIV  word ptr HzInOrder[si]   ;除法，低位放在ax,高位放在dx,商放在ax中
   
   OUT 42H,al  
   MOV al,ah
   OUT 42h,al             ;分两次输送数据，先送低字节再送高字节 
   POP AX
   RET
    
DIVMOVE ENDP    
;----------------------------------------------------------------------
code ends
end start ; set entry point and stop the assembler.