+void
+useRTC(void)
+{
+ u16 ebda_seg = get_ebda_seg();
+ int count = GET_EBDA2(ebda_seg, RTCusers);
+ SET_EBDA2(ebda_seg, RTCusers, count+1);
+ if (count)
+ return;
+ // Turn on the Periodic Interrupt timer
+ u8 bRegister = inb_cmos(CMOS_STATUS_B);
+ outb_cmos(bRegister | RTC_B_PIE, CMOS_STATUS_B);
+}
+
+void
+releaseRTC(void)
+{
+ u16 ebda_seg = get_ebda_seg();
+ int count = GET_EBDA2(ebda_seg, RTCusers);
+ SET_EBDA2(ebda_seg, RTCusers, count-1);
+ if (count != 1)
+ return;
+ // Clear the Periodic Interrupt.
+ u8 bRegister = inb_cmos(CMOS_STATUS_B);
+ outb_cmos(bRegister & ~RTC_B_PIE, CMOS_STATUS_B);
+}
+