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-rw-r--r--cpukit/score/src/kern_ntptime.c24
1 files changed, 7 insertions, 17 deletions
diff --git a/cpukit/score/src/kern_ntptime.c b/cpukit/score/src/kern_ntptime.c
index 1233166a61..c6f70079b3 100644
--- a/cpukit/score/src/kern_ntptime.c
+++ b/cpukit/score/src/kern_ntptime.c
@@ -782,8 +782,7 @@ RTEMS_SYSINIT_ITEM(_NTP_Initialize, RTEMS_SYSINIT_DEVICE_DRIVERS,
* is selected by the STA_MODE status bit.
*/
static void
-hardupdate(offset)
- long offset; /* clock offset (ns) */
+hardupdate(long offset /* clock offset (ns) */)
{
long mtemp;
l_fp ftemp;
@@ -862,11 +861,11 @@ hardupdate(offset)
* variables, except for the actual time and frequency variables, which
* are determined by this routine and updated atomically.
*
- * tsp - time at PPS
- * nsec - hardware counter at PPS
+ * tsp - time at current PPS event
+ * delta_nsec - time elapsed between the previous and current PPS event
*/
void
-hardpps(struct timespec *tsp, long nsec)
+hardpps(struct timespec *tsp, long delta_nsec)
{
long u_sec, u_nsec, v_nsec; /* temps */
l_fp ftemp;
@@ -901,19 +900,10 @@ hardpps(struct timespec *tsp, long nsec)
pps_tf[0].tv_nsec = u_nsec;
/*
- * Compute the difference between the current and previous
- * counter values. If the difference exceeds 0.5 s, assume it
- * has wrapped around, so correct 1.0 s. If the result exceeds
- * the tick interval, the sample point has crossed a tick
- * boundary during the last second, so correct the tick. Very
- * intricate.
+ * Update the frequency accumulator using the difference between the
+ * current and previous PPS event measured directly by the timecounter.
*/
- u_nsec = nsec;
- if (u_nsec > (NANOSECOND >> 1))
- u_nsec -= NANOSECOND;
- else if (u_nsec < -(NANOSECOND >> 1))
- u_nsec += NANOSECOND;
- pps_fcount += u_nsec;
+ pps_fcount += delta_nsec - NANOSECOND;
if (v_nsec > MAXFREQ || v_nsec < -MAXFREQ)
goto out;
time_status &= ~STA_PPSJITTER;