Asm中的串行端口

asm中的串行端口

.MODEL small
.STACK 100h
.data
.code
_start:
mov ax,@data
mov ds,ax
mov ah, 0           ;Initialize opcode
mov al, 11100011b   ;Parameter data.
mov dx, 0           ;COM1: port.
int 14h
again:
   mov  dx, 0           ;Select COM1:
   mov  al, 'm'        ;Character to transmit
   mov  ah, 1           ;Transmit opcode
   int  14h
   jmp again   
mov ah,1
int 21h
END _start