ysk3.asm

4.asm…… 响铃程序

       STACK  SEGMENT   STACK
              DB        512 DUP(?)
       STACK  ENDS
        DATA  SEGMENT
     STRING1  DB        '* $ '
     STRING2  DB        0DH,0AH,'$'
        DATA  ENDS
        CODE  SEGMENT
              ASSUME    DS:DATA,CS:CODE
START:
              MOV       AX,DATA
              MOV       DS,AX
      
              MOV       CX,10
    REAGAIN:  SUB       CX,1
              CMP       CX,0
              JNE       AGAIN
              JMP       EXIT
               
      AGAIN:  MOV       BX,CX
    AGAIN_1:  MOV       AH,09H
              MOV       DX,OFFSET STRING1
              INT       21H
              ADD       BX,-1
              CMP       BX,0
              JNE       AGAIN_1
              MOV       AH,09H
              MOV       DX,OFFSET STRING2
              INT       21H
              JMP       REAGAIN
       EXIT:  MOV       AH,1
              INT       21H
              MOV       AX,4C00H
              INT       21H
        CODE  ENDS
              END       START