;在AX中存放有两字节四位十六进制数,将其转换为四字节的
;ASCII码存放在以s2为首址的四个字节单元中。
data segment
s1 dw 3f5ah
s2 db 4 dup(?)
data ends
code segment
assume cs:code,ds:data
start:mov ax,data
      mov ds,ax
      mov ax,s1
      lea di,s2
      mov ch,4
j1:   mov bx,ax
      and ax,0fh
      add al,30h
      cmp al,3ah
      jb j2
      add al,7
j2:   mov [di],al
      inc di
      mov ax,bx
      mov cl,4
      shr ax,cl
      dec ch
      jnz j1
;---------------------
      mov cx,4
l1:   dec di
      mov ah,2
      mov dl,[di]
      int 21h
      loop l1
      mov ah,2
      mov dl,'H'
      int 21h
      mov ah,4ch
      int 21h
code  ends
      end start