1  /* Check __ppc_get_timebase_freq() for architecture changes
       2     Copyright (C) 2012-2023 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     <https://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"