sysdeps/unix/sysv/linux/powerpc/test-gettimebasefreq.c

   1 /* Check __ppc_get_timebase_freq() for architecture changes
   2    Copyright (C) 2012-2013 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 /* Test if __ppc_get_timebase_freq() works and is different from zero.  A read
  20    failure might indicate a Linux Kernel change.
  21    This test also use the frequency to compute the real elapsed time.  */
  22
  23 #include <inttypes.h>
  24 #include <stdio.h>
  25
  26 #include <sys/platform/ppc.h>
  27
  28 /* Maximum value of the Time Base Register: 2^60 - 1.  */
  29 #define MAX_TB 0xFFFFFFFFFFFFFFF
  30
  31 static int
  32 do_test (void)
  33 {
  34   uint64_t t1, t2, f, diff;
  35
  36   t1 = __ppc_get_timebase ();
  37   printf ("t1 = %"PRIu64"\n", t1);
  38
  39   f = __ppc_get_timebase_freq ();
  40   printf ("Time Base frequency = %"PRIu64" Hz\n", f);
  41
  42   if (f == 0) {
  43       printf ("Fail: The time base frequency can't be zero.");
  44       return 1;
  45   }
  46
  47   t2 = __ppc_get_timebase ();
  48   printf ("t2 = %"PRIu64"\n", t2);
  49
  50   if (t2 > t1) {
  51     diff = t2 - t1;
  52   } else {
  53     diff = (MAX_TB - t2) + t1;
  54   }
  55
  56   printf ("Elapsed time  = %1.2f usecs\n", (double) diff * 1000000 / f );
  57
  58   return 0;
  59 }
  60
  61 #define TEST_FUNCTION do_test ()
  62 #include "../test-skeleton.c"