pps_gen_get_time: optimized for minimum register reads

b8dcb5ae · Aurelio Colosimo · eb204b22 · b8dcb5ae
Commit b8dcb5ae authored Jul 09, 2012 by Aurelio Colosimo
Hide whitespace changes
Inline Side-by-side

Showing with 9 additions and 11 deletions

pps_gen.c arch-spec/dev/pps_gen.c +9 -11

No files found.
--- a/arch-spec/dev/pps_gen.c
+++ b/arch-spec/dev/pps_gen.c
@@ -82,19 +82,17 @@ int pps_gen_busy()

 void pps_gen_get_time(uint32_t *utc, uint32_t *cntr_nsec)
 {
-	uint32_t cyc_before, cyc_after;
-	uint32_t utc_lo;
+	uint32_t nsec;
+	uint32_t utc_lo1, utc_lo2;

-	do {
-		cyc_before = PPSG->CNTR_NSEC & 0xfffffff;
-		utc_lo = PPSG->CNTR_UTCLO;
-		cyc_after = PPSG->CNTR_NSEC & 0xfffffff;
-	} while (cyc_after < cyc_before);
+	utc_lo1 = PPSG->CNTR_UTCLO;
+	nsec = PPSG->CNTR_NSEC & 0xfffffff;
+	utc_lo2 = PPSG->CNTR_UTCLO;
+	if (utc_lo2 != utc_lo1)
+		nsec = PPSG->CNTR_NSEC & 0xfffffff;

-//	delay(100000);
-
-	if(utc) *utc = utc_lo;
-	if(cntr_nsec) *cntr_nsec = cyc_after;
+	if(utc) *utc = utc_lo2;
+	if(cntr_nsec) *cntr_nsec = nsec;
 }