/* High precision, low overhead timing functions.  AArch64 version.
   Copyright (C) 2021 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
   <https://www.gnu.org/licenses/>.  */

#ifndef _HP_TIMING_H
#define _HP_TIMING_H	1

#include <time.h>
#include <stdint.h>
#include <hp-timing-common.h>
#include <libc-symbols.h>

/* Don't use inline timer in ld.so.  */
#if IS_IN(rtld)
# define HP_TIMING_INLINE	(0)
#else
# define HP_TIMING_INLINE	(1)
#endif

typedef uint64_t hp_timing_t;

#define HP_TIMING_NOW(var) \
  __asm__ __volatile__ ("isb; mrs %0, cntvct_el0" : "=r" (var))

/* Compute elapsed time in nanoseconds.  */
#undef HP_TIMING_DIFF
#define HP_TIMING_DIFF(Diff, Start, End)			\
({  hp_timing_t freq;						\
    __asm__ __volatile__ ("mrs %0, cntfrq_el0" : "=r" (freq));	\
   (Diff) = ((End) - (Start)) * (UINT64_C(1000000000) / freq);	\
})

#endif	/* hp-timing.h */