PIC_SLAVE_MASK
out8(in8(PIC_SLAVE_MASK) & ~(1 << (num - PIC_SLAVE_INT_BASE)), PIC_SLAVE_MASK);
out8(in8(PIC_SLAVE_MASK) | (1 << (num - PIC_SLAVE_INT_BASE)), PIC_SLAVE_MASK);
out8(0xff, PIC_SLAVE_MASK); // Mask off interrupts on the slave.
enabledInterrupts = ~(in8(PIC_MASTER_MASK) | in8(PIC_SLAVE_MASK) << 8);
out8(0xff, PIC_SLAVE_MASK);
#define PIC_SLAVE_INIT2 PIC_SLAVE_MASK
#define PIC_SLAVE_INIT3 PIC_SLAVE_MASK
#define PIC_SLAVE_INIT4 PIC_SLAVE_MASK