Global: Define MSEC_PER_SEC, MSEC_PER_WEEK, SEC_PER_WEEK and UNIX_OFFSET.

libraries/AP_GPS/AP_GPS.cpp

@@ -611,9 +611,9 @@ AP_GPS::setHIL(uint8_t instance, GPS_Status _status, uint64_t time_epoch_ms,
     istate.hdop = hdop;
     istate.num_sats = _num_sats;
     istate.last_gps_time_ms = tnow;
-    uint64_t gps_time_ms = time_epoch_ms - (17000ULL*86400ULL + 52*10*7000ULL*86400ULL - GPS_LEAPSECONDS_MILLIS);
+    uint64_t gps_time_ms = time_epoch_ms - UNIX_OFFSET;
-    istate.time_week     = gps_time_ms / (86400*7*(uint64_t)1000);
+    istate.time_week     = gps_time_ms / MSEC_PER_WEEK;
-    istate.time_week_ms  = gps_time_ms - istate.time_week*(86400*7*(uint64_t)1000);
+    istate.time_week_ms  = gps_time_ms - istate.time_week * MSEC_PER_WEEK;
     timing[instance].last_message_time_ms = tnow;
     timing[instance].last_fix_time_ms = tnow;
     _type[instance].set(GPS_TYPE_HIL);

libraries/AP_GPS/AP_GPS.h

@@ -34,6 +34,8 @@
 // the number of GPS leap seconds
 #define GPS_LEAPSECONDS_MILLIS 18000ULL
 
+#define UNIX_OFFSET (17000ULL * 86400ULL + 52 * 10 * MSEC_PER_WEEK - GPS_LEAPSECONDS_MILLIS)
+
 class DataFlash_Class;
 class AP_GPS_Backend;
 

libraries/AP_GPS/GPS_Backend.cpp

@@ -63,9 +63,7 @@ int16_t AP_GPS_Backend::swap_int16(int16_t v) const
  */
 uint64_t AP_GPS::time_epoch_convert(uint16_t gps_week, uint32_t gps_ms)
 {
-    const uint64_t ms_per_week = 7000ULL*86400ULL;
+    uint64_t fix_time_ms = UNIX_OFFSET + gps_week * MSEC_PER_WEEK + gps_ms;
-    const uint64_t unix_offset = 17000ULL*86400ULL + 52*10*7000ULL*86400ULL - GPS_LEAPSECONDS_MILLIS;
-    uint64_t fix_time_ms = unix_offset + gps_week*ms_per_week + gps_ms;
     return fix_time_ms;
 }
 
@@ -120,8 +118,8 @@ void AP_GPS_Backend::make_gps_time(uint32_t bcd_date, uint32_t bcd_milliseconds)
     ret -= 272764785UL;
 
     // get GPS week and time
-    state.time_week = ret / (7*86400UL);
+    state.time_week = ret / SEC_PER_WEEK;
-    state.time_week_ms = (ret % (7*86400UL)) * 1000;
+    state.time_week_ms = (ret % SEC_PER_WEEK) * MSEC_PER_SEC;
     state.time_week_ms += msec;
 }
 

libraries/AP_HAL_SITL/sitl_gps.cpp

@@ -179,10 +179,10 @@ static void gps_time(uint16_t *time_week, uint32_t *time_week_ms)
     simulation_timeval(&tv);
     const uint32_t epoch = 86400*(10*365 + (1980-1969)/4 + 1 + 6 - 2) - (GPS_LEAPSECONDS_MILLIS / 1000ULL);
     uint32_t epoch_seconds = tv.tv_sec - epoch;
-    *time_week = epoch_seconds / (86400*7UL);
+    *time_week = epoch_seconds / SEC_PER_WEEK;
     uint32_t t_ms = tv.tv_usec / 1000;
     // round time to nearest 200ms
-    *time_week_ms = (epoch_seconds % (86400*7UL))*1000 + ((t_ms/200) * 200);
+    *time_week_ms = (epoch_seconds % SEC_PER_WEEK) * MSEC_PER_SEC + ((t_ms/200) * 200);
 }
 
 /*

libraries/AP_Math/definitions.h

@@ -68,3 +68,6 @@ static const double WGS84_E = (sqrt(2 * WGS84_F - WGS84_F * WGS84_F));
 #define NSEC_PER_USEC   1000ULL
 #define USEC_PER_SEC    1000000ULL
 #define USEC_PER_MSEC   1000ULL
+#define MSEC_PER_SEC    1000UL
+#define SEC_PER_WEEK    (7UL * 86400UL)
+#define MSEC_PER_WEEK   (SEC_PER_WEEK * MSEC_PER_SEC)