[gomp-nvptx 06/13] libgomp: add nvptx time.c

[Alexander Monakov <amonakov at ispras dot ru>]

This patch implements time.c on NVPTX with the %clock64 register.  The PTX
documentation describes %globaltimer as explicitely off-limits for us.

	* config/nvptx/time.c: New.
---
 libgomp/ChangeLog.gomp-nvptx |  4 ++++
 libgomp/config/nvptx/time.c  | 49 ++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 53 insertions(+)

diff --git a/libgomp/config/nvptx/time.c b/libgomp/config/nvptx/time.c
index e69de29..08feafe 100644
--- a/libgomp/config/nvptx/time.c
+++ b/libgomp/config/nvptx/time.c
@@ -0,0 +1,49 @@
+/* Copyright (C) 2015 Free Software Foundation, Inc.
+   Contributed by Dmitry Melnik <dm@ispras.ru>
+
+   This file is part of the GNU Offloading and Multi Processing Library
+   (libgomp).
+
+   Libgomp is free software; you can redistribute it and/or modify it
+   under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3, or (at your option)
+   any later version.
+
+   Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY
+   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
+   FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+   more details.
+
+   Under Section 7 of GPL version 3, you are granted additional
+   permissions described in the GCC Runtime Library Exception, version
+   3.1, as published by the Free Software Foundation.
+
+   You should have received a copy of the GNU General Public License and
+   a copy of the GCC Runtime Library Exception along with this program;
+   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+   <http://www.gnu.org/licenses/>.  */
+
+/* This file implements timer routines for NVPTX.  It uses the %clock64 cycle
+   counter.  */
+
+#include "libgomp.h"
+
+/* This is set from host in plugin-nvptx.c.  */
+double __nvptx_clocktick = 0;
+
+double
+omp_get_wtime (void)
+{
+  uint64_t clock;
+  asm ("mov.u64 %0, %%clock64;" : "=r" (clock));
+  return clock * __nvptx_clocktick;
+}
+
+double
+omp_get_wtick (void)
+{
+  return __nvptx_clocktick;
+}
+
+ialias (omp_get_wtime)
+ialias (omp_get_wtick)