org 100h

terminar equ 4ch

mov ah, 4fh
mov al, 02
mov bx,13h
int 10h
mov [cor],8;cor
mov [col],100;coluna incial
mov [lin],100;linha incial
mov [tam],50;
mov [sentido], '1'
call reta
mov [cor],1;cor
mov [col],150;coluna incial
mov [lin],50;linha incial
mov [tam],50;
mov [sentido], '2'
call reta
mov [cor],4;cor
mov [col],100;coluna incial
mov [lin],100;linha incial
mov [tam],100;
mov [sentido], '3'
call reta
        mov ah, 07h
        int 21h

;leitura para parar o ecran
mov ah, terminar
int 21h

pixel:
        mov ah,0ch
        mov bh,0
        int 10h
        ret
reta:
   mov cx,[col]
   mov dx,[lin]
ciclo:
   call pixel
   cmp [sentido], '1'
   je obA
   cmp [sentido], '2'
   je obB
   cmp [sentido], '3'
   je hor

   jmp sai
   obA:
   inc cx
   dec dx
   jmp segue
   obB:
   inc cx
   inc dx
   jmp segue
   hor:
   inc cx
   jmp segue
segue:
   dec byte[tam]
jnz ciclo

  sai:
   ret
        tam rb 1;
        cor rb 1;
        lin rw 1;
        col rw 1;
        sentido rb 1;