shithub: pt2-clone

Info  •  Files  •  Log  •  Branches

Added more bits for fractional part of HPC timers

--- a/src/pt2_hpc.c

+++ b/src/pt2_hpc.c

@@ -1,5 +1,5 @@

 /*

-** High Performance Counter delay routines

+** Hardware Performance Counter delay routines

 */

 #ifdef _WIN32

@@ -13,6 +13,10 @@

 #include <stdbool.h>

 #include "pt2_hpc.h"

+#define FRAC_BITS 53

+#define FRAC_SCALE (1ULL << FRAC_BITS)

+#define FRAC_MASK (FRAC_SCALE-1)

+

 hpcFreq_t hpcFreq;

 #ifdef _WIN32 // Windows usleep() implementation

@@ -68,9 +72,9 @@

 	double dDurationInt;

 	double dDurationFrac = modf(dDuration, &dDurationInt);

-	// set 64:32 values

-	hpc->duration64Int = (uint64_t)floor(dDurationInt);

-	hpc->duration64Frac = (uint64_t)((dDurationFrac * (UINT32_MAX+1.0)) + 0.5); // rounded

+	// set 64:53fp values

+	hpc->duration64Int = (uint64_t)dDurationInt;

+	hpc->duration64Frac = (uint64_t)round(dDurationFrac * FRAC_SCALE);

 }

 void hpc_ResetEndTime(hpc_t *hpc)

@@ -113,9 +117,9 @@

 	hpc->endTime64Int += hpc->duration64Int;

 	hpc->endTime64Frac += hpc->duration64Frac;

-	if (hpc->endTime64Frac > UINT32_MAX)

+	if (hpc->endTime64Frac >= FRAC_SCALE)

 	{

-		hpc->endTime64Frac &= UINT32_MAX;

+		hpc->endTime64Frac &= FRAC_MASK;

 		hpc->endTime64Int++;

 	}

 }