OCW3_SEL
atpic_write(sc, icu, 0, OCW3_SEL | OCW3_RR);
atpic_write(sc, ATPIC_MASTER, 0, OCW3_SEL | OCW3_P);
atpic_write(sc, ATPIC_MASTER, 0, OCW3_SEL | OCW3_RR);
atpic_write(sc, ATPIC_SLAVE, 0, OCW3_SEL | OCW3_P);
atpic_write(sc, ATPIC_SLAVE, 0, OCW3_SEL | OCW3_RR);
outb(pic->at_ioaddr, OCW3_SEL | OCW3_RR);
outb(port, OCW3_SEL | OCW3_RR | OCW3_RIS);
outb(port, OCW3_SEL | OCW3_RR);
outb(IO_ICU1, OCW3_SEL | OCW3_RR);
outb(IO_ICU2, OCW3_SEL | OCW3_RR);