+/* Programmable Interrupt Controller (PIC) registers.
+ A PC has two PICs, called the master and slave PICs, with the
+ slave attached ("cascaded") to the master IRQ line 2. */
+#define PIC0_CTRL 0x20 /* Master PIC control register address. */
+#define PIC0_DATA 0x21 /* Master PIC data register address. */
+#define PIC1_CTRL 0xa0 /* Slave PIC control register address. */
+#define PIC1_DATA 0xa1 /* Slave PIC data register address. */
+