paracommr.asm

大学微型计算机接口技术实验源代码,直接就可以运行,包含了C++和asm代码,比较前面.

;*-------------------------------------------------------*/
;*    ParaCommR.asm(双机并行通信接口实验－接收端程序)         */
;*    并行通信接收程序 Source File                        */
;*    Copyright (c) 2001 by HUST                         */
;*		Modify	 Date	2005.4.10											*/
;*------------------------------------------------------ */

Stack1 segment
dw  200 dup(?)
stack1 ends
data     segment
message  db'now receiving, please wait ! '   ;系统提示信息
         db 0dh,0ah
         db'strike "esc" to exit',0dh,0ah,'$'
wait_mes db'send no ready ! if want to exit,please strike ESC',0DH,0AH,'$'
data     ends
code     segment
         assume cs:code,ds:data,ss:stack1
start:  mov ax,data
         mov ds,ax               ;取程序数据段地址
         mov ax,stack1    
          mov ss,ax          
main proc near
         mov  dx,303h             ;初始化8255
         mov  al,10011000b
         out  dx,al
         mov  al,00000111b         ;置ACK=1
         out  dx,al

         lea dx,message
         mov ah,09h              ;显示系统提示信息
         int 21h 
    
    L:   mov  ah,0bh             ;查有任意键按下？
         int  21h
         cmp  al,0
         je   m2                 ;若无，则转查有数据接收？
         mov  ah,08h
         int  21h
         cmp  al,1bh             ;若是ESC键，则退出
         jz   over 
     
m2:      mov  dx,302h            ;查有数据接收？
         in   al,dx
         and  al,80h
         jnz   l                   ;若无数据接收，则继续查任意键按下

         mov  dx,300h             ;若有数据接收，则接收1个字符
         in   al,dx
         mov  dl,al
         mov  ah,02h              ;显示1个字符
         int  21h

         mov  dx,303h             ;发送回答信号ACK
         mov  al,00000110b
         out  dx,al
         nop 
         nop
         mov  al,00000111b
         out  dx,al

delay1:  mov  cx,1000
lop:     loop lop
         jmp  L                    ;继续

over:    mov  ax,4c00h             ;程序退出
         int  21h
main  endp
code  ends
     end start