4.asm

汇编发声程序

 title  musex--TONE  OF  DO  -RE-MI  
STACK  SEGMENT  PARA  STACK  'STACK'  
           DB  200  DUP('STACK.......')  
STACK  ENDS  
dseg  segment  para  'data'  
         
mus_freq  DW 220,262,330,330,330,294,330,330,330,294,330,294,262,262,100,330,294 
DW 330,294,262,294,262,247,262,247,220,220,100,220,262 
DW 330,330,330,294,330,330,330,294,330,294,262,262,100,330,294 
DW 330,294,262,294,330,220,220,100,-1 
mus_time  DW 12 DUP(25),50,4 DUP(25) 
DW 25,50,25,25,50,25,25,25,25,50,25,25,25,25 
DW 12 DUP(25),50,4 DUP(25) 
DW 25,50,25,25,50,50,100,25,25 
 
dseg  ends  
 
cseg  segment  para  'code'  
         assume  cs:cseg,ss:stack,ds:dseg  
tone  proc            far  
         push            ds                            ;put  return  addr.  
         sub              ax,ax                      ;    on  stack  
         push            ax  
         mov              ax,dseg                  ;initialize  DS  
           
         lea              si,mus_freq              ;freq  table  offset  in  SI  
next:lea              bp,mus_time                ;time  table  offset  in  BP  
 
freq:mov              di,[si]                  ;read  next  frequency  
         cmp              di,-1                      ;end  of  tone?  
         je                end_f                      ;yes,one  time  is  end  
         mov              bx,ds:[bp]            ;no,fetch  the  duration  
 
         mov              al,0b6h                  ;put  magic  number  
         out              43h,al                    ;      into    timer2  
         mov              dx,12h  
         mov              ax,533h*896  
         div              di                            ;(dx,ax)/(DI)  
         out              42h,al                    ;LSB  into  timer2  
         mov              al,ah  
         out              42h,al                    ;MSB  into  timer2  
         in                al,61h  
         mov              ah,al  
         or                al,3                        ;turn  speake  on  
         out              61h,al  
long:mov              cx,2801                  ;length  of  tone  
delay:loop          delay  
           dec            bx  
           jnz            long  
           mov            al,ah                      ;recover  the  port  
           out            61h,al  
 
           
           add            si,2                        ;inc  the  freq  pointer  
         
cont:  add            bp,2                        ;update  mus_t  pointer  
           jmp            freq                        ;go  process  next  note  
end_f:  
           mov            al,48h                    ;reset  port  
           out            61h,al  
           ret  
tone  endp  
cseg  ends  
;  
           end  tone