glibc/sysdeps/aarch64/hp-timing.h

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/* High precision, low overhead timing functions. AArch64 version.
Copyright (C) 2021-2022 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 */