Implement system time management functions

xtoskrnl/ke/systime.cc

@@ -0,0 +1,99 @@
+/**
+ * PROJECT:         ExectOS
+ * COPYRIGHT:       See COPYING.md in the top level directory
+ * FILE:            xtoskrnl/ke/systime.cc
+ * DESCRIPTION:     Timebase and system clock support
+ * DEVELOPERS:      Aiken Harris <harraiken91@gmail.com>
+ */
+
+#include <xtos.hh>
+
+
+/**
+ * Returns the current system time.
+ *
+ * @param SystemTime
+ *        Supplies a pointer to a variable that receives the current system time.
+ *
+ * @return This routine does not return any value.
+ *
+ * @since XT 1.0
+ */
+XTAPI
+VOID
+KE::SystemTime::GetSystemTime(OUT PLARGE_INTEGER SystemTime)
+{
+    LARGE_INTEGER CurrentTime;
+
+    /* Fetch the time using the lock-free shared data mechanism and return it */
+    CurrentTime = KE::SharedData::GetSystemTime();
+    SystemTime->QuadPart = CurrentTime.QuadPart;
+}
+
+/**
+ * Sets the system time, updates the boot time, and optionally updates the hardware Real-Time Clock (RTC).
+ *
+ * @param NewTime
+ *        Supplies a pointer to the new system time.
+ *
+ * @param OldTime
+ *        Supplies a pointer to a variable that receives the previous system time.
+ *
+ * @param AdjustInterruptTime
+ *        Specifies if the physical interrupt time should be adjusted.
+ *
+ * @param WriteToRtc
+ *        Specifies if the new system time should be written to RTC.
+ *
+ * @return This routine does not return any value.
+ *
+ * @since XT 1.0
+ */
+XTAPI
+VOID
+KE::SystemTime::SetSystemTime(IN PLARGE_INTEGER NewTime,
+                              OUT PLARGE_INTEGER OldTime,
+                              IN BOOLEAN CorrectInterruptTime,
+                              IN BOOLEAN WriteToRtc)
+{
+    LARGE_INTEGER TimeDelta;
+    TIME_FIELDS TimeFields;
+
+    /* Check if the new system time should be written to the RTC */
+    if(WriteToRtc)
+    {
+        /* Convert the new system time to a human-readable calendar structure */
+        RTL::Time::XtEpochToTimeFields(NewTime, &TimeFields);
+    }
+
+    /* Start a guarded code block */
+    {
+        /* Raise runlevel to HIGH level */
+        KE::RaiseRunLevel Runlevel(HIGH_LEVEL);
+
+        /* Save the previous system time for the caller and for delta calculation */
+        GetSystemTime(OldTime);
+
+        /* Write new system time to the Kernel Shared Data */
+        KE::SharedData::SetSystemTime(*NewTime);
+
+        /* Check if the new system time should be written to the RTC */
+        if(WriteToRtc)
+        {
+            /* Update the hardware CMOS clock */
+            HL::Rtc::SetRealTimeClock(&TimeFields);
+        }
+
+        /* Calculate the time difference */
+        TimeDelta.QuadPart = NewTime->QuadPart - OldTime->QuadPart;
+
+        /* Update the boot time by the delta */
+        BootTime.QuadPart += TimeDelta.QuadPart;
+    }
+
+    /* Check if interrupt time needs to be corrected */
+    if(CorrectInterruptTime)
+    {
+        UNIMPLEMENTED;
+    }
+}