1 files changed, 19 insertions, 6 deletions

diff --git a/mcs/class/corlib/System/DateTime.cs b/mcs/class/corlib/System/DateTime.cs
index 2c1a193fed7..af483154ee0 100644
--- a/mcs/class/corlib/System/DateTime.cs
+++ b/mcs/class/corlib/System/DateTime.cs
@@ -431,6 +431,18 @@ namespace System
 

 			return AddTicks (msticks);

 		}

+
+		// required to match MS implementation for OADate (OLE Automation)
+		private DateTime AddRoundedMilliseconds (double ms)

+		{

+			if ((ms * TimeSpan.TicksPerMillisecond) > long.MaxValue ||
+				(ms * TimeSpan.TicksPerMillisecond) < long.MinValue) {
+ 				throw new ArgumentOutOfRangeException ();
+ 			}
+			long msticks = (long) (ms += ms > 0 ? 0.5 : -0.5) * TimeSpan.TicksPerMillisecond;
+
+			return AddTicks (msticks);

+		}

 

 		public DateTime AddMinutes (double minutes)

 		{

@@ -551,17 +563,18 @@ namespace System
 			if (d < 0.0d) {
 				Double days = Math.Ceiling (d);
 				// integer part is the number of days (negative)
-				dt = dt.AddDays (days);
+				dt = dt.AddRoundedMilliseconds (days * 86400000);
 				// but decimals are the number of hours (in days fractions) and positive
 				Double hours = (days - d);
-				dt = dt.AddDays (hours);
+				dt = dt.AddRoundedMilliseconds (hours * 86400000);
+			}
+			else {
+				dt = dt.AddRoundedMilliseconds (d * 86400000);
 			}
-			else
-				dt = dt.AddDays (d);
 
 			return dt;

-		}

-

+		}
+
 		public string[] GetDateTimeFormats() 

 		{

 			return GetDateTimeFormats (CultureInfo.CurrentCulture);