sysdeps/x86_64/hp-timing.h

   1 /* High precision, low overhead timing functions.  x86-64 version.
   2    Copyright (C) 2002-2014 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 #ifndef _HP_TIMING_H
  20
  21 /* We can use some of the i686 implementation without changes.  */
  22 # include <sysdeps/i386/i686/hp-timing.h>
  23
  24 /* The "=A" constraint used in 32-bit mode does not work in 64-bit mode.  */
  25 # undef HP_TIMING_NOW
  26 # define HP_TIMING_NOW(Var) \
  27   ({ unsigned int _hi, _lo; \
  28      asm volatile ("rdtsc" : "=a" (_lo), "=d" (_hi)); \
  29      (Var) = ((unsigned long long int) _hi << 32) | _lo; })
  30
  31 /* The funny business for 32-bit mode is not required here.  */
  32 # undef HP_TIMING_ACCUM
  33 # define HP_TIMING_ACCUM(Sum, Diff)                                           \
  34   do {                                                                        \
  35     hp_timing_t __diff = (Diff) - GLRO(dl_hp_timing_overhead);                \
  36     __asm__ __volatile__ ("lock; addq %1, %0"                                 \
  37                           : "=m" (Sum) : "r" (__diff), "m" (Sum));            \
  38   } while (0)
  39
  40 #endif /* hp-timing.h */