rem: dprintf("arch_int_enable_io_interrupt: irq %d\n", irq);
context: arch_int_enable_io_interrupt(int irq){	if (irq < 0 || irq >= 0x10)		return;	dprintf("arch_int_enable_io_interrupt: irq %d\n", irq);	/* if this is a external interrupt via 8239, enable it here */	if (irq < 8)		out8(in8(0x21) & ~(1 << irq), 0x21);	else		out8(in8(0xa1) & ~(1 << (irq - 8)), 0xa1);}