524.asm

本书为清华大学第二版汇编语言的课后题详解

;524.asm

datasg  segment
branch_table dw song_1
             dw song_2
             dw song_3
             dw song_4
             dw song_5
datasg  ends
codesg  segment
main    proc  far
        assume cs:codesg, ds:datasg
start:
        push  ds
        sub   ax,ax
        push  ax
        mov   ax,datasg
        mov   ds,ax
input:  mov   ah,1
        int   21h
        sub   al,30h
        cmp   al,1
        jl    exit
        cmp   al,5
        jg    exit
        sub   al,1
        mov   bl,2
        mul   bl
        mov   si,ax
        jmp   word ptr branch_table[si]
song_1: mov   cx,1
loop1:  mov   dl,07h
        mov   ah,2
        int   21h
        loop  loop1
        jmp   short  exit
song_2: mov   cx,2
loop2:  mov   dl,07h
        mov   ah,2
        int   21h
        loop  loop2
        jmp   short  exit
song_3: mov   cx,3
loop3:  mov   dl,07h
        mov   ah,2
        int   21h
        loop  loop3
        jmp   short  exit
song_4: mov   cx,4
loop4:  mov   dl,07h
        mov   ah,2
        int   21h
        loop  loop4
        jmp   short  exit
song_5: mov   cx,5
loop5:  mov   dl,07h
        mov   ah,2
        int   21h
        loop  loop5
exit:   ret
main    endp
codesg  ends
        end    start