1  /* High precision, low overhead timing functions.  AArch64 version.
       2     Copyright (C) 2021-2023 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  #include <time.h>
      23  #include <stdint.h>
      24  #include <hp-timing-common.h>
      25  #include <libc-symbols.h>
      26  
      27  /* Don't use inline timer in ld.so.  */
      28  #if IS_IN(rtld)
      29  # define HP_TIMING_INLINE	(0)
      30  #else
      31  # define HP_TIMING_INLINE	(1)
      32  #endif
      33  
      34  typedef uint64_t hp_timing_t;
      35  
      36  #define HP_TIMING_NOW(var) \
      37    __asm__ __volatile__ ("isb; mrs %0, cntvct_el0" : "=r" (var))
      38  
      39  /* Compute elapsed time in nanoseconds.  */
      40  #undef HP_TIMING_DIFF
      41  #define HP_TIMING_DIFF(Diff, Start, End)			\
      42  ({  hp_timing_t freq;						\
      43      __asm__ __volatile__ ("mrs %0, cntfrq_el0" : "=r" (freq));	\
      44     (Diff) = (((End) - (Start)) * UINT64_C(1000000000 >> 6)) / (freq >> 6); \
      45  })
      46  
      47  #endif	/* hp-timing.h */