From 7897d6d886900521c0264353604bcad10ee350de Mon Sep 17 00:00:00 2001
From: Erik Lindahl <erik@kth.se>
Date: Tue, 19 Aug 2014 14:29:57 +0200
Subject: [PATCH] Add cycle counters for 64-bit ARM

The gcc code has been tested on actual ARM64
hardware, but the MSVC one is only implemented
from the MSVC manual.

Change-Id: I13aac4d65345c684b6ddc5812ca9c3fcbe27b81a
---
 src/gromacs/timing/cyclecounter.h | 31 +++++++++++++++++++++++++++++--
 1 file changed, 29 insertions(+), 2 deletions(-)

diff --git a/src/gromacs/timing/cyclecounter.h b/src/gromacs/timing/cyclecounter.h
index 87d19b19a1..7751db4390 100644
--- a/src/gromacs/timing/cyclecounter.h
+++ b/src/gromacs/timing/cyclecounter.h
@@ -79,6 +79,11 @@ extern "C"
 typedef unsigned long long
     gmx_cycles_t;
 
+#elif ((defined __aarch64__) && (defined(__GNUC__) || defined(__INTEL_COMPILER) || defined(__PATHSCALE__) || defined(__PGIC__)))
+/* 64-bit ARM cycle counters with GCC inline assembly */
+typedef unsigned long long
+    gmx_cycles_t;
+
 #elif defined(_MSC_VER)
 #include <windows.h>
 typedef __int64
@@ -210,6 +215,12 @@ static __inline__ int gmx_cycles_have_counter(void)
     /* x86 or x86-64 with GCC inline assembly - pentium TSC register */
     return 1;
 }
+#elif ((defined __aarch64__) && (defined(__GNUC__) || defined(__INTEL_COMPILER) || defined(__PATHSCALE__) || defined(__PGIC__)))
+static __inline int gmx_cycles_have_counter(void)
+{
+    /* 64-bit ARM cycle counters with GCC inline assembly */
+    return 1;
+}
 #elif (defined(_MSC_VER))
 static __inline int gmx_cycles_have_counter(void)
 {
@@ -350,14 +361,30 @@ static __inline__ gmx_cycles_t gmx_cycles_read(void)
 
     return cycle;
 }
+#elif ((defined __aarch64__) && (defined(__GNUC__) || defined(__INTEL_COMPILER) || defined(__PATHSCALE__) || defined(__PGIC__)))
+static __inline__ gmx_cycles_t gmx_cycles_read(void)
+{
+    /* 64-bit ARM cycle counters with GCC inline assembly */
+    gmx_cycles_t   cycle;
+    __asm__ __volatile__("mrs %0, cntvct_el0" : "=r" (cycle) );
+
+    return cycle;
+}
+
 #elif defined(_MSC_VER)
 static __inline gmx_cycles_t gmx_cycles_read(void)
 {
-#ifdef HAVE_RDTSCP
+#ifdef _M_ARM
+    /* Windows on 64-bit ARM */
+    return __rdpmccntr64();
+#else
+    /* x86 */
+#    ifdef HAVE_RDTSCP
     unsigned int ui;
     return __rdtscp(&ui);
-#else
+#    else
     return __rdtsc();
+#    endif
 #endif
 }
 #elif (defined(__hpux) || defined(__HP_cc)) && defined(__ia64)
-- 
2.22.0