sysdeps/powerpc/powerpc32/power4/hp-timing.h

   1 /* High precision, low overhead timing functions.  powerpc64 version.
   2    Copyright (C) 2005-2022 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 #ifndef _HP_TIMING_H
  20 #define _HP_TIMING_H    1
  21
  22 /* We indeed have inlined functions.  */
  23 #define HP_TIMING_INLINE        (1)
  24
  25 /* We use 64bit values for the times.  */
  26 typedef unsigned long long int hp_timing_t;
  27
  28 /* That's quite simple.  Use the `mftb' instruction.  Note that the value
  29    might not be 100% accurate since there might be some more instructions
  30    running in this moment.  This could be changed by using a barrier like
  31    'lwsync' right before the `mftb' instruction.  But we are not interested
  32    in accurate clock cycles here so we don't do this.  */
  33
  34 #define HP_TIMING_NOW(Var)                                              \
  35   do {                                                                  \
  36     unsigned int hi, lo, tmp;                                           \
  37     __asm__ __volatile__ ("1:   mfspr   %0,269;"                        \
  38                           "     mfspr   %1,268;"                        \
  39                           "     mfspr   %2,269;"                        \
  40                           "     cmpw    %0,%2;"                         \
  41                           "     bne     1b;"                            \
  42                           : "=&r" (hi), "=&r" (lo), "=&r" (tmp)         \
  43                           : : "cr0");                                   \
  44     Var = ((hp_timing_t) hi << 32) | lo;                                \
  45   } while (0)
  46
  47 #include <hp-timing-common.h>
  48
  49 #endif  /* hp-timing.h */