Fix up gpsprof's dime difference calculation and add a mtching C macro.

All regression tests pass. PPS is live.

2 files changed, 3 insertions, 1 deletions

diff --git a/gps.h b/gps.h
index 53d63f10..108e0419 100644
--- a/gps.h
+++ b/gps.h
@@ -1891,6 +1891,8 @@ struct timedrift_t {
     struct timespec	real;
     struct timespec	clock;
 };
+#define TIMEDIFF(drift)	((((drift)->real.tv_sec - (drift)->clock.tv_sec)*1e9)\
+			 + ((drift)->real.tv_nsec - (drift)->clock.tv_nsec))
 
 /*
  * Someday we may support Windows, under which socket_t is a separate type.
diff --git a/gpsprof b/gpsprof
index 05fe4736..da34305a 100755
--- a/gpsprof
+++ b/gpsprof
@@ -271,7 +271,7 @@ class timeplot(plotter):
 set autoscale
 set key below
 set key title "System clock delta from GPS time"
-plot "-" using 0:(column(3)*1000000000+column(4)-(column(1)*1000000000+column(2))) title "Delta" with impulses
+plot "-" using 0:((column(1)-column(3))*1e9 + (column(2)-column(4))) title "Delta" with impulses
 '''
         return fmt + self.header() + self.data()