Andrew Boyson / clock

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Dependents:   oldheating gps motorhome heating

Files at this revision

API Documentation at this revision

Revision 55:e18983651004, committed 2019-02-21

Comitter:
andrewboyson
Date:
Thu Feb 21 15:42:49 2019 +0000
Parent:
54:a3c018ceca77
Child:
56:3e4fe2d3db4e
Commit message:
Optimised conversion between utc and tai.

Changed in this revision

clk/clkutc.c Show annotated file Show diff for this revision Revisions of this file 
--- a/clk/clkutc.c	Thu Feb 21 12:47:15 2019 +0000
+++ b/clk/clkutc.c	Thu Feb 21 15:42:49 2019 +0000
@@ -22,11 +22,13 @@
 */
 
 //Leap seconds
-static int epochOffset = 0; //12 bits holds enough leap seconds for at least 300 years.
+static int     epochOffset   = 0; //12 bits holds enough leap seconds for at least 300 years.
+static int64_t epochOffset64 = 0;
 int  ClkUtcGetEpochOffset() { return epochOffset; }
 void ClkUtcSetEpochOffset(int value)
 {
-    epochOffset = value;
+    epochOffset   = value;
+    epochOffset64 = (int64_t)epochOffset << CLK_TIME_ONE_SECOND_SHIFT;
     GPREG1 = GPREG1 & 0xFFFF0000 | value & 0x0000FFFF;
 }
 void ClkUtcAddEpochOffset(int value)
@@ -76,16 +78,17 @@
 
 void ClkUtcInit(void)
 {
-    epochOffset             =  GPREG1 & 0x0000FFFF;
-    nextEpochMonth1970      = (GPREG1 & 0x0FFF0000) >> 16;
+    epochOffset         =  GPREG1 & 0x0000FFFF;
+    epochOffset64       = (int64_t)epochOffset << CLK_TIME_ONE_SECOND_SHIFT;
+    nextEpochMonth1970  = (GPREG1 & 0x0FFF0000) >> 16;
     makeNextEpochUtc();
-    nextLeapEnable          =  GPREG1 & 0x10000000;
-    nextLeapForward         =  GPREG1 & 0x20000000;
+    nextLeapEnable      =  GPREG1 & 0x10000000;
+    nextLeapForward     =  GPREG1 & 0x20000000;
 }
 
 
-int64_t ClkUtcFromTai(int64_t tai) { return tai - ((int64_t)epochOffset << CLK_TIME_ONE_SECOND_SHIFT); }
-int64_t ClkUtcToTai  (int64_t utc) { return utc + ((int64_t)epochOffset << CLK_TIME_ONE_SECOND_SHIFT); }
+int64_t ClkUtcFromTai(int64_t tai) { return tai - epochOffset64; }
+int64_t ClkUtcToTai  (int64_t utc) { return utc + epochOffset64; }
 
 void    ClkUtcCheckAdjustLeapSecondCount(int64_t tai)
 {