sysdeps/powerpc/nptl/pthread_spin_lock.c

   1 /* Copyright (C) 2003-2015 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3    Contributed by Paul Mackerras <paulus@au.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   unsigned int __tmp;
  25
  26   asm volatile (
  27        "1:      lwarx   %0,0,%1" MUTEX_HINT_ACQ "\n"
  28        "        cmpwi   0,%0,0\n"
  29        "        bne-    2f\n"
  30        "        stwcx.  %2,0,%1\n"
  31        "        bne-    2f\n"
  32                 __ARCH_ACQ_INSTR "\n"
  33        "        .subsection 1\n"
  34        "2:      lwzx    %0,0,%1\n"
  35        "        cmpwi   0,%0,0\n"
  36        "        bne     2b\n"
  37        "        b       1b\n"
  38        "        .previous"
  39        : "=&r" (__tmp)
  40        : "r" (lock), "r" (1)
  41        : "cr0", "memory");
  42   return 0;
  43 }