macro putchar() {
    @1 = 0; // write
    @2 = 10; // ptr
    @3 = 1; // size
    @10 = /1/; // value
    system(); // interrupt (@0 = 2; halt;)
}

putchar(['h']);
putchar(['e']);
putchar(['l']);
putchar(['l']);
putchar(['o']);

exit(0);