关于跳跃地址表的实现

DATAS SEGMENT
table  dw prog4,prog1,prog2,prog3,prog4
lat1   db 0ah,0dh,'(1)    GUESS NUMBER GAME       $'
lat2   db 0ah,0dh,'(2)    CHAR SELECTION PROGRAM  $'
lat3   db 0ah,0dh,'(3)    PASSWORD PROGRAM        $'
lat4   db 0ah,0dh,'(4)    PRESS  "ESC" TO  QUIT   $'

mess1 db 0ah,0dh,'input 1-4:$'
mess2 db 0ah,0dh,'Your selection is 1,the program will execute GUESS NUMBER GAME!$'
mess3 db 0ah,0dh,'Your selection is 2,the program will execute CHAR SELECTION PROGRAM!$'
mess4 db 0ah,0dh,'Your selection is 3,the program will execute PASSWORD PROGRAM!$'
mess5 db 0ah,0dh,'Your selection is 4,the program will execute PRESS  "ESC"  TO  QUIT!$'
mess6 db 0ah,0dh,'will you continue program really?(Y:N)$'
mess7 db 0ah,0dh,'Please press ESC key to exit!$'

M db '5'
N db ?
str11 db 0ah,0dh,'now please input a number: ','$'
str12 db 'TOO BIG','$'
str13 db 'TOO SMALL','$'
str14 db 'YOUR ARE RIGHT','$'

str21 db 0ah,0dh,'you can input "<CR>" to go out,if you want go on ,please input others besides "<CR>" $'
str22 db 0ah,0dh,'you input:','$'
str23 db 0ah,0dh,'IT IS A DIGITAL','$'
str24 db 0ah,0dh,'IT IS A LOWCASE LETTER','$'

str31 db '123'   
str32 db 0ah,0dh,'please input a string:','$'
len equ str32-str31  
str_d db 50,?,50 dup(?)
mess31 db 0ah,0dh,'MATCH!$'
mess32 db 0ah,0dh,'NOMATCH!,PROGRAM TERMINATED!$'
DATAS ENDS

CODES SEGMENT
    ASSUME CS:CODES,DS:DATAS
START:
    MOV AX,DATAS
    MOV DS,AX
    push ax
mas:
   lea dx,lat1
   mov ah,09h
   int 21h
   lea dx,lat2
   mov ah,09h
   int 21h
   lea dx,lat3
   mov ah,09h
   int 21h
   lea dx,lat4
   mov ah,09h
   int 21h
  
   mov dx,offset mess1
   mov ah,09h
   int 21h
   mov ah,1
   int 21h
   and al,03h
   mov ah,0
   shl ax,1
   mov bx,ax
   push bx
to:  jmp table[bx]
prog1:
    mov dx,offset mess2
    mov ah,09h
    int 21h
    mov bl,M
    mov dx,offset str11
    mov ah,09h
    int 21h
    mov ah,01h
    int 21h
    mov N,al
    cmp bl,al
    jb  a
    cmp bl,al
    ja  b
    mov dl,0ah
    mov ah,02h
    int 21h
    mov dl,0dh
    int 21h
    mov dx,offset str14
    mov ah,09h
    int 21h
    jmp let1
a:  mov dl,0ah
    mov ah,02h
    int 21h
    mov dl,0dh
    int 21h
    mov dx,offset str13
    mov ah,09h
    int 21h
    jmp let1
b:  mov dl,0ah
    mov ah,02h
    int 21h
    mov dl,0dh
    int 21h
    mov dx,offset str12
    mov ah,09h
    int 21h   
    jmp let1

 
prog2:
    lea dx,mess3
    mov ah,09h
    int 21h
    mov dx,offset str21
    mov ah,09h
    int 21h
    mov dx,offset str22
    mov ah,09h
    int 21h
    mov ah,01h
    int 21h
    cmp al,0dh
    jz exit
    cmp al,'1'   
    jb another
    cmp al,'9'
    ja another
    mov dx,offset str23
    mov ah,09h
    int 21h
    jmp let1
another:
      cmp al,'A'
      jb  another2
      cmp al,'Z'
      ja  another2
      mov dx,offset str24
      mov ah,09h
      int 21h
      jmp let1
another2:
      cmp al,'a'
      jb  another3
      cmp al,'z'
      ja  another3
      mov dx,offset str24
      mov ah,09h
      int 21h
      jmp let1
another3:
      jmp let1
     
prog3:
    lea dx,mess4
    mov ah,09h
    int 21h
    mov dx,offset str32
    mov ah,09h
    int 21h
    pop ax
    mov es,ax
    lea dx,str_d
    mov ah,0ah
    int 21h
    xor cx,cx
    mov cl,str_d+1
    cmp cl,len
    jne ms
    lea si,str31
    lea di,str_d+2
mad:mov al,ds:[si]
    mov bl,es:[di]
    cmp al,bl
    jne ms
    inc si
    inc di
    loop mad
    lea dx,mess31
    mov ah,09h
    int 21h
    jmp  let1
ms:
    lea dx,mess32
    mov ah,09h
    int 21h        
let1:
  pop bx
  lea dx,mess6
  mov ah,09h
  int 21h
  mov ah,01h
  int 21h
  cmp al,'Y'
  jz to
  cmp al,'N'
  jz mas
prog4:
   lea dx,mess5
   mov ah,09h
   int 21h
   lea dx,mess7
   mov ah,09h
   int 21h
   mov ah,01h
   int 21h
   cmp al,27
   jZ exit
   jmp mas
exit:    MOV AH,4CH
    INT 21H
CODES ENDS
    END START