8253-1.asm

用8253编制秒表延迟程序

;定时器8253的例子:利用BIOS调用INT1AH/00H取得计时单位(55MS),在屏幕上每个;以5秒间隔从1到8显示
DATA   SEGMENT
       SED  DB '0'
DATA   ENDS  
STACK  SEGMENT STACK
       DW  64  DUP(0)
STACK  ENDS

CODE   SEGMENT
       ASSUME CS:CODE,SS:STACK,DS:DATA

START:   MOV   AX,DATA
         MOV   DS,AX
   GOT:  MOV   AH,00H
         INT   1AH               ;BIOS调用,取计时单位(55ms),在DX
         ADD   DX,91             ;5s/55ms=5000ms/55ms=91 
         MOV   BX,DX
   LOP:  MOV   AH,00H
         INT   1AH
         CMP   DX,BX
         JNZ   LOP
         MOV   DL,SED
         MOV   AH,02H            ;DOS调用,显示一个字符
         INT   21H
         INC   SED
         CMP   SED,'9'
         JNZ   GOT 
         MOV   SED,'0'
         MOV   AH,4CH
         INT   21H           
CODE  ENDS
      END   START