1  /* Copyright (C) 2003-2023 Free Software Foundation, Inc.
       2     This file is part of the GNU C Library.
       3  
       4     The GNU C Library is free software; you can redistribute it and/or
       5     modify it under the terms of the GNU Lesser General Public
       6     License as published by the Free Software Foundation; either
       7     version 2.1 of the License, or (at your option) any later version.
       8  
       9     The GNU C Library is distributed in the hope that it will be useful,
      10     but WITHOUT ANY WARRANTY; without even the implied warranty of
      11     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      12     Lesser General Public License for more details.
      13  
      14     You should have received a copy of the GNU Lesser General Public
      15     License along with the GNU C Library; if not, see
      16     <https://www.gnu.org/licenses/>.  */
      17  
      18  #include "pthreadP.h"
      19  #include <shlib-compat.h>
      20  
      21  int
      22  __pthread_spin_lock (pthread_spinlock_t *lock)
      23  {
      24    int *p = (int *) lock;
      25  
      26    while (__builtin_expect (__sync_val_compare_and_swap (p, 0, 1), 0))
      27      {
      28        /* Spin without using the atomic instruction.  */
      29        do
      30  	__asm __volatile ("hint @pause" : : : "memory");
      31        while (*p);
      32      }
      33    return 0;
      34  }
      35  versioned_symbol (libc, __pthread_spin_lock, pthread_spin_lock,
      36                    GLIBC_2_34);
      37  
      38  #if OTHER_SHLIB_COMPAT (libpthread, GLIBC_2_2, GLIBC_2_34)
      39  compat_symbol (libpthread, __pthread_spin_lock, pthread_spin_lock,
      40                 GLIBC_2_2);
      41  #endif