汇编作业 16和10进制的相互转换

data segment
    firstline db "cin 1(hex to dec) or 2(dec to hec) (cin # means exit):$"
ends

display equ 2h
key_in  equ 1h
doscall equ 21h
hexidec segment
;---------------------------------
main proc far
    start:
         mov  ax, data
         mov  ds, ax
         mov  es, ax
         lea  dx, firstline
         mov  ah, 9
         int  doscall

         ;-------------------
         mov  ah, key_in
         int  doscall
         push ax
         call crlf
         pop  ax
         cmp  al,31h
         je   hextodec
         cmp  al,32h
         je   dectohex

dectohex:                   ;10进制换成16进制
         call decibin
         call crlf
         call binihex
         call crlf
         jmp  start
hextodec:                   ;十六进制换成10进制
         call hexibin
         call crlf
         call binidec
         call crlf
         jmp  start
         main endp
;----------------------------------------
hexibin  proc near         ;16-->2
         mov  bx,0
newchar:
         mov  ah,key_in    ;输入1位字符
         int  doscall
         cmp  al,'#'
         je   exit
         sub  al,30h       ;小于0，退出
         jl   exit
         cmp  al,10d       ;不大于10
         jl   add_to

         sub  al,7h        ;al-=7
         cmp  al,0ah
         jl   exit         ;比'A'小,退出
         cmp  al,10h       ;比较al和'G'
         jge  exit         ;大于等于'G'，退出
add_to:
         mov  cl,4
         shl  bx,cl      ;bx左移4位,bx+=ax
         mov  ah,0
         add  bx,ax
         jmp  newchar
exit:
         ret
hexibin  endp
;------------------------------------
binidec  proc near
         mov  cx,10000d  ;bx/10000
         call dec_div
         mov  cx,1000d   ;bx/1000
         call dec_div
         mov  cx,100d
         call dec_div
         mov  cx,10d
         call dec_div
         mov  cx,1d
         call dec_div
         ret
binidec  endp
;--------------------------------------
dec_div  proc near
         mov  ax,bx
         mov  dx,0
         div  cx        ;dx,ax/cx
         mov  bx,dx     ;商
         mov  dl,al     ;余数

         add  dl,30h
         mov  ah,display
         int  doscall
         ret
dec_div  endp
;-----------------------------
crlf     proc near            ;输出回车
         mov  dl,0ah
         mov  ah,display
         int  doscall

         mov  dl,0dh
         mov  ah,display
         int  doscall
         ret
crlf     endp
;---------------------------
hexidec  ends
;===============================
decibin  proc near           ;10-->2
         mov  bx,0
newchar1:
         mov  ah,key_in
         int  doscall
         cmp  al,'#'
         je   exit1
         sub  al,30h          ;al-'0'
         jl   exit1           ;小于0
         cmp  al,9d
         jg   exit1           ;大于9
         cbw                  ;8位-->16位
         xchg ax,bx           ;bx<--ax
         mov  cx,10d
         mul  cx              ;ax*=10
         xchg ax,bx

         add  bx,ax
         jmp  newchar1
exit1:
         ret
decibin  endp
;---------------------------------
binihex  proc near
         mov  ch,4          ;bx为16位，要做四次
rotate:  mov  cl,4
         rol  bx,cl         ;循环右移4位，即bx/16
         mov  al,bl         ;bl-->al
         and  al,0fh        ;al & 00001111
         add  al,30h
         cmp  al,3ah        ;比较al和"10"
         jl   print
         add  al,7h         ;'10'-->'A'
print:
         mov  dl,al
         mov  ah,display
         int  doscall
         dec  ch
         jnz  rotate
         ret
binihex  endp
;--------------------------------
         end  start

学汇编，伤不起，没本事，更伤不起。