sysdeps/s390/nptl/pthread_spin_lock.c

   1 /* Copyright (C) 2003-2016 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Martin Schwidefsky <schwidefsky@de.ibm.com>, 2003.
   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    <http://www.gnu.org/licenses/>.  */
  18
  19 #include "pthreadP.h"
  20
  21 int
  22 pthread_spin_lock (pthread_spinlock_t *lock)
  23 {
  24   int oldval;
  25
  26   __asm__ __volatile__ ("0: lhi %0,0\n"
  27                         "   cs  %0,%2,%1\n"
  28                         "   jl  0b"
  29                         : "=&d" (oldval), "=Q" (*lock)
  30                         : "d" (1), "m" (*lock) : "cc" );
  31   return 0;
  32 }