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

   1 /* Check __ppc_get_timebase_freq() for architecture changes
   2    Copyright (C) 2012-2015 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 #include <stdint.h>
  26
  27 #include <sys/platform/ppc.h>
  28
  29 /* Maximum value of the Time Base Register: 2^60 - 1.  */
  30 #define MAX_TB 0xFFFFFFFFFFFFFFF
  31
  32 static int
  33 do_test (void)
  34 {
  35   uint64_t t1, t2, f, diff;
  36
  37   t1 = __ppc_get_timebase ();
  38   printf ("t1 = %"PRIu64"\n", t1);
  39
  40   f = __ppc_get_timebase_freq ();
  41   printf ("Time Base frequency = %"PRIu64" Hz\n", f);
  42
  43   if (f == 0) {
  44       printf ("Fail: The time base frequency can't be zero.\n");
  45       return 1;
  46   }
  47
  48   t2 = __ppc_get_timebase ();
  49   printf ("t2 = %"PRIu64"\n", t2);
  50
  51   if (t2 > t1) {
  52     diff = t2 - t1;
  53   } else {
  54     diff = (MAX_TB - t2) + t1;
  55   }
  56
  57   printf ("Elapsed time  = %1.2f usecs\n", (double) diff * 1000000 / f );
  58
  59   return 0;
  60 }
  61
  62 #define TEST_FUNCTION do_test ()
  63 #include "../test-skeleton.c"