LAB 4 IS DONE.

lab/kern/kclock.c

@@ -0,0 +1,22 @@
+/* See COPYRIGHT for copyright information. */
+
+/* Support for reading the NVRAM from the real-time clock. */
+
+#include <inc/x86.h>
+
+#include <kern/kclock.h>
+
+
+unsigned
+mc146818_read(unsigned reg)
+{
+	outb(IO_RTC, reg);
+	return inb(IO_RTC+1);
+}
+
+void
+mc146818_write(unsigned reg, unsigned datum)
+{
+	outb(IO_RTC, reg);
+	outb(IO_RTC+1, datum);
+}