ArduCopter: fixed print_latlon bug in which it would print negative lat/lon numbers incorrectly (i.e. -1234567890 would be printed as -124.xxx).

ArduCopter/Log.pde

@@ -220,13 +220,20 @@ process_logs(uint8_t argc, const Menu::arg *argv)
 	return 0;
 }
 
-
 // print_latlon - prints an latitude or longitude value held in an int32_t
 // probably this should be moved to AP_Common
 void print_latlon(BetterStream *s, int32_t lat_or_lon)
 {
-    int32_t dec_portion = lat_or_lon / T7;
-    int32_t frac_portion = labs(lat_or_lon - dec_portion*T7);
+	int32_t dec_portion, frac_portion;
+
+	// extract decimal portion (special handling of negative numbers to ensure we round towards zero)
+    dec_portion = labs(lat_or_lon) / T7;
+	if( lat_or_lon < 0 ){
+		dec_portion = -dec_portion;
+	}
+
+	// extract fractional portion
+    frac_portion = labs(lat_or_lon - dec_portion*T7);
     s->printf("%ld.%07ld",(long)dec_portion,(long)frac_portion);
 }
 

libraries/AP_GPS/examples/GPS_AUTO_test/GPS_AUTO_test.pde

@@ -17,13 +17,21 @@ AP_GPS_Auto GPS(&Serial1, &gps);
 #define T6 1000000
 #define T7 10000000
 
-// print_latlon - prints an latitude or longitude value held in an int32_t 
+// print_latlon - prints an latitude or longitude value held in an int32_t
 // probably this should be moved to AP_Common
 void print_latlon(BetterStream *s, int32_t lat_or_lon)
 {
-    int32_t dec_portion = lat_or_lon / T7;
-	int32_t frac_portion = labs(lat_or_lon - dec_portion*T7);
-	s->printf("%ld.%07ld",dec_portion,frac_portion);
+	int32_t dec_portion, frac_portion;
+
+	// extract decimal portion (special handling of negative numbers to ensure we round towards zero)
+    dec_portion = labs(lat_or_lon) / T7;
+	if( lat_or_lon < 0 ){
+		dec_portion = -dec_portion;
+	}
+
+	// extract fractional portion
+    frac_portion = labs(lat_or_lon - dec_portion*T7);
+    s->printf("%ld.%07ld",(long)dec_portion,(long)frac_portion);
 }
 
 void setup()