Implement clock()

Newlib uses _times_r() in clock().  The problem is that the _times_r()
clock frequency is defined by sysconf(_SC_CLK_TCK).  The clock frequency
of clock() is the constant CLOCKS_PER_SEC.

FreeBSD uses getrusage() for clock().  Since RTEMS has only one process,
the implementation can be simplified.

Update #3121.

1 files changed, 33 insertions, 0 deletions

diff --git a/cpukit/libcsupport/src/clock.c b/cpukit/libcsupport/src/clock.c
new file mode 100644
index 0000000000..f976221a78
--- /dev/null
+++ b/cpukit/libcsupport/src/clock.c
@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2017 embedded brains GmbH.  All rights reserved.
+ *
+ *  embedded brains GmbH
+ *  Dornierstr. 4
+ *  82178 Puchheim
+ *  Germany
+ *  <rtems@embedded-brains.de>
+ *
+ * The license and distribution terms for this file may be
+ * found in the file LICENSE in this distribution or at
+ * http://www.rtems.org/license/LICENSE.
+ */
+
+#if HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <time.h>
+
+#include <rtems/score/basedefs.h>
+#include <rtems/score/timecounter.h>
+
+RTEMS_STATIC_ASSERT( CLOCKS_PER_SEC == 1000000, clocks_per_sec );
+
+clock_t clock( void )
+{
+  struct timeval tv;
+
+  _Timecounter_Microuptime( &tv );
+
+  return (clock_t) (tv.tv_sec - 1) * CLOCKS_PER_SEC + tv.tv_usec;
+}