2-13.asm

华工电信系汇编习题的编程实现

stack segment stack 'stack'
      dw 32 dup(?)
stack ends

data segment 
     FIRST dd 0FFFFFFFBH
     Forth db 4 dup(0)
data ends

code segment 
begin proc far
      assume ss:stack,cs:code,ds:data
      push ds
      sub ax,ax
      push ax
      mov ax,data
      mov ds,ax

      mov bx,word ptr FIRST + 2
      mov dx,bx
      and dx,0F0H
      JZ ZHENG
      and bh,07FH
      NOT bx
      mov dx,bx
      mov bx,word ptr FIRST
      NOT bx
      add bx,1
      adc dx,0
      mov Forth,dh
      mov Forth +1,dl
      mov Forth +2,bh
      mov Forth +3,bl
      JMP MYEND
ZHENG:
      mov bx,word ptr FIRST + 2
      mov Forth,bh
      mov Forth +1,bl
      mov bx,word ptr FIRST
      mov Forth +2,bh
      mov Forth +3,bl
      
MYEND:

      ret
begin   endp
code    ends
      end begin