MOV BL,3F;

loop:
IN 00;
INC BL;
MOV [BL],AL;

CMP BL,7F;
JZ init;
CMP AL,0D;
JNZ loop;

init:
MOV CL,C0;
MOV DL,40;
list:
MOV AL,[DL]
MOV [CL],AL;
PUSH DL;
POP AL;
INC DL;
INC CL;
CMP AL,BL;
JNZ list;