INT2_CTL0
outb(INT2_CTL0, ICW1_AT); /* ICW1 */
outb(irc_no ? INT2_CTL0 : INT_CTL0, OCW3_PL);
data = inb(irc_no ? INT2_CTL0 : INT_CTL0);
outb(INT2_CTL0, OCW2_CLEAR | (irq_no >> 3));