glibc/sysdeps/x86_64/hp-timing.h

/* High precision, low overhead timing functions.  x86-64 version.
   Copyright (C) 2002-2017 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

#ifndef _HP_TIMING_H
#define _HP_TIMING_H	1

/* We always assume having the timestamp register.  */
#define HP_TIMING_AVAIL		(1)
#define HP_SMALL_TIMING_AVAIL	(1)

/* We indeed have inlined functions.  */
#define HP_TIMING_INLINE	(1)

/* We use 64bit values for the times.  */
typedef unsigned long long int hp_timing_t;

/* The "=A" constraint used in 32-bit mode does not work in 64-bit mode.  */
#define HP_TIMING_NOW(Var) \
  ({ unsigned int _hi, _lo; \
     asm volatile ("rdtsc" : "=a" (_lo), "=d" (_hi)); \
     (Var) = ((unsigned long long int) _hi << 32) | _lo; })

#include <hp-timing-common.h>

#endif /* hp-timing.h */