From 3d147a032c688342dfa681d9f82e157f9ef42682 Mon Sep 17 00:00:00 2001
From: "alexey.lysiuk" <alexey.lysiuk@gmail.com>
Date: Tue, 31 Jan 2017 17:51:12 +0200
Subject: [PATCH] Proper RDTSC implementation for x86_64 targets

Higher 32 bits of Time Stamp Counter were ignored in non-MSVC Windows and macOS builds
---
 src/stats.h | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/src/stats.h b/src/stats.h
index 8ac1e978a..f18159616 100644
--- a/src/stats.h
+++ b/src/stats.h
@@ -102,7 +102,7 @@ private:
 
 #else
 
-// Windows
+// Windows and macOS
 #include "x86.h"
 
 extern double PerfToSec, PerfToMillisec;
@@ -126,15 +126,19 @@ inline unsigned __int64 rdtsc()
 #else
 inline unsigned long long rdtsc()
 {
-#ifndef __amd64__
+#ifdef __amd64__
+	unsigned long long tsc;
+	asm volatile ("rdtsc; shlq $32, %%rdx; orq %%rdx, %%rax" : "=a" (tsc) :: "%rdx");
+	return tsc;
+#else // i386
 	if (CPU.bRDTSC)
-#endif
 	{
 		unsigned long long tsc;
 		asm volatile ("\trdtsc\n" : "=A" (tsc));
 		return tsc;
 	}
 	return 0;
+#endif // __amd64__
 }
 #endif