diff --git a/SOPE/NGCards/ChangeLog b/SOPE/NGCards/ChangeLog
index fbac587b8..b66b3e49d 100644
--- a/SOPE/NGCards/ChangeLog
+++ b/SOPE/NGCards/ChangeLog
@@ -1,3 +1,9 @@
+2008-01-28  Wolfgang Sourdeau  <wsourdeau@inverse.ca>
+
+	* iCalDailyRecurrenceCalculator.m ([iCalDailyRecurrenceCalculator
+	-recurrenceRangesWithinCalendarDateRange:]): make use of <<
+	instead of exp2 to compute the mask.
+
 2008-01-22  Wolfgang Sourdeau  <wsourdeau@inverse.ca>
 
 	* iCalRecurrenceRule.m ([iCalRecurrenceRule -repeatInterval]):
diff --git a/SOPE/NGCards/iCalDailyRecurrenceCalculator.m b/SOPE/NGCards/iCalDailyRecurrenceCalculator.m
index 7c7d2656c..6c9fd423b 100644
--- a/SOPE/NGCards/iCalDailyRecurrenceCalculator.m
+++ b/SOPE/NGCards/iCalDailyRecurrenceCalculator.m
@@ -23,18 +23,16 @@
 #import <Foundation/NSArray.h>
 
 #import <NGExtensions/NSCalendarDate+misc.h>
+#import <NGExtensions/NGCalendarDateRange.h>
+
+#import "NSCalendarDate+ICal.h"
 
 #import "iCalRecurrenceCalculator.h"
+#import "iCalRecurrenceRule.h"
 
 @interface iCalDailyRecurrenceCalculator : iCalRecurrenceCalculator
 @end
 
-#import <NGExtensions/NGCalendarDateRange.h>
-#import "iCalRecurrenceRule.h"
-#import "NSCalendarDate+ICal.h"
-
-#include <math.h>
-
 @interface iCalRecurrenceCalculator(PrivateAPI)
 - (NSCalendarDate *)lastInstanceStartDate;
 @end
@@ -105,7 +103,9 @@
 	// FIXME: Should we also check the end date? We might want
 	//        to check if the end date is also within it.
 	if ([self->rrule byDayMask]) {
-	  mask = [start dayOfWeek] == 0 ? iCalWeekDaySunday : (unsigned int)exp2([start dayOfWeek]-1);
+	  mask = ([start dayOfWeek]
+		  ? (unsigned int) 1 << ([start dayOfWeek] - 1)
+		  : iCalWeekDaySunday);
 	  if (([self->rrule byDayMask]&mask) != mask) continue;
 	}