SHA* digest function speed test.

src/platform/vboot_reference/tests/timer_utils.c

+/* Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "timer_utils.h"
+
+void StartTimer(ClockTimerState* ct) {
+  clock_gettime(CLOCK_REALTIME, &ct->start_time);
+}
+
+void StopTimer(ClockTimerState* ct) {
+  clock_gettime(CLOCK_REALTIME, &ct->end_time);
+}
+
+uint32_t GetDurationMsecs(ClockTimerState* ct) {
+  uint64_t start = ((uint64_t) ct->start_time.tv_sec * 1000000000 +
+                    (uint64_t) ct->start_time.tv_nsec);
+  uint64_t end = ((uint64_t) ct->end_time.tv_sec * 1000000000 +
+                  (uint64_t) ct->end_time.tv_nsec);
+  uint64_t duration_msecs = (end - start) / 1000000U;  /* Nanoseconds ->
+                                                        * Milliseconds. */
+  return (uint32_t) duration_msecs;
+}