Assembler


         

300


= 03F8 SERIAL EQU 03F8H
 
0000 CODE SEGMENT
ASSUME CS:CODE
0000 ASYNC PROC FAR
0000 1E PUSH DS ;
0001 2B C0 SUB AX,AX
0003 50 PUSH AX
0004 BA 03FB MOV DX,SERIAL+3 ;
0007 B0 80 MOV AL,80H
0009 EE OUT DX,AL ;
000A B8 0180 MOV AX,384 ; 300
000D BA 03F8 MOV DX,SERIAL
0010 EE OUT DX,AL ;
0011 8A C4 MOV AL,AH
 
. 8.16 ()
0013 42 INC DX
0014 EE OUT DX,AL ;
0015 BA 03FB MOV DX,SERIAL+3 ;
0018 B0 03 MOV AL,00000011b ; ,8
001A EE OUT DX,AL
 
;-----
 
001B BA 03FD MOV DX,SERIAL+5 ;
001E SEND:
001E EC IN AL,DX
001F A8 20 TEST AL,20H
0021 74 FB JZ SEND
0023 B0 41 MOV AL,'A'
0025 BA 03F8 MOV DX,SERIAL