glibc/sysdeps/s390/nptl/pthread_spin_lock.c

/* Copyright (C) 2003-2015 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Martin Schwidefsky <schwidefsky@de.ibm.com>, 2003.

   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
   <http://www.gnu.org/licenses/>.  */

#include "pthreadP.h"

int
pthread_spin_lock (pthread_spinlock_t *lock)
{
  int oldval;

  __asm__ __volatile__ ("0: lhi %0,0\n"
			"   cs  %0,%2,%1\n"
			"   jl  0b"
			: "=&d" (oldval), "=Q" (*lock)
			: "d" (1), "m" (*lock) : "cc" );
  return 0;
}