glibc/sysdeps/sh/nptl/pthread_spin_lock.c

/* Copyright (C) 2003-2020 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/>.  */

#include "pthreadP.h"

int
pthread_spin_lock (pthread_spinlock_t *lock)
{
  unsigned int val;

  do
    asm volatile ("tas.b @%1; movt %0"
		  : "=&r" (val)
		  : "r" (lock)
		  : "memory");
  while (val == 0);

  return 0;
}