[HVM] Move RTC emulation into the hypervisor.

Signed-off-by: Xiaowei Yang <xiaowei.yang@intel.com>

1 files changed, 77 insertions, 0 deletions

diff --git a/xen/common/time.c b/xen/common/time.c
new file mode 100644
index 0000000000..65929d1c1f
--- /dev/null
+++ b/xen/common/time.c
@@ -0,0 +1,77 @@
+/******************************************************************************
+ * time.c
+ * 
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ * 
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ * 
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <xen/config.h>
+#include <xen/time.h>
+
+/* Nonzero if YEAR is a leap year (every 4 years,
+   except every 100th isn't, and every 400th is).  */
+#define __isleap(year) \
+  ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))
+
+/* How many days are in each month.  */
+const unsigned short int __mon_lengths[2][12] = {
+    /* Normal years.  */
+    {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
+    /* Leap years.  */
+    {31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}
+};
+
+#define SECS_PER_HOUR (60 * 60)
+#define SECS_PER_DAY  (SECS_PER_HOUR * 24)
+
+struct tm gmtime(unsigned long t)
+{
+    struct tm tbuf;
+    long days, rem;
+    int y;
+    unsigned short int *ip;
+
+    days = t / SECS_PER_DAY;
+    rem = t % SECS_PER_DAY;
+
+    tbuf.tm_hour = rem / SECS_PER_HOUR;
+    rem %= SECS_PER_HOUR;
+    tbuf.tm_min = rem / 60;
+    tbuf.tm_sec = rem % 60;
+    /* January 1, 1970 was a Thursday.  */
+    tbuf.tm_wday = (4 + days) % 7;
+    if ( tbuf.tm_wday < 0 )
+        tbuf.tm_wday += 7;
+    y = 1970;
+    while ( days >= (rem = __isleap(y) ? 366 : 365) )
+    {
+        ++y;
+        days -= rem;
+    }
+    while ( days < 0 )
+    {
+        --y;
+        days += __isleap(y) ? 366 : 365;
+    }
+    tbuf.tm_year = y - 1900;
+    tbuf.tm_yday = days;
+    ip = (unsigned short int *)__mon_lengths[__isleap(y)];
+    for ( y = 0; days >= ip[y]; ++y )
+        days -= ip[y];
+    tbuf.tm_mon = y;
+    tbuf.tm_mday = days + 1;
+    tbuf.tm_isdst = -1;
+
+    return tbuf;
+}