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[/] [openrisc/] [trunk/] [gnu-dev/] [or1k-gcc/] [libgomp/] [config/] [linux/] [ptrlock.c] - Blame information for rev 735

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1 735 jeremybenn
/* Copyright (C) 2008, 2009, 2011 Free Software Foundation, Inc.
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   Contributed by Jakub Jelinek <jakub@redhat.com>.
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   This file is part of the GNU OpenMP Library (libgomp).
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   Libgomp is free software; you can redistribute it and/or modify it
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   under the terms of the GNU General Public License as published by
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   the Free Software Foundation; either version 3, or (at your option)
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   any later version.
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   Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY
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   WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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   FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
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   more details.
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   Under Section 7 of GPL version 3, you are granted additional
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   permissions described in the GCC Runtime Library Exception, version
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   3.1, as published by the Free Software Foundation.
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   You should have received a copy of the GNU General Public License and
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   a copy of the GCC Runtime Library Exception along with this program;
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   see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
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   <http://www.gnu.org/licenses/>.  */
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/* This is a Linux specific implementation of a mutex synchronization
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   mechanism for libgomp.  This type is private to the library.  This
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   implementation uses atomic instructions and the futex syscall.  */
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#include <endian.h>
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#include <limits.h>
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#include "wait.h"
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void *
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gomp_ptrlock_get_slow (gomp_ptrlock_t *ptrlock)
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{
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  int *intptr;
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  uintptr_t oldval = 1;
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  __atomic_compare_exchange_n (ptrlock, &oldval, 2, false,
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                               MEMMODEL_RELAXED, MEMMODEL_RELAXED);
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  /* futex works on ints, not pointers.
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     But a valid work share pointer will be at least
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     8 byte aligned, so it is safe to assume the low
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     32-bits of the pointer won't contain values 1 or 2.  */
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  __asm volatile ("" : "=r" (intptr) : "0" (ptrlock));
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#if __BYTE_ORDER == __BIG_ENDIAN
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  if (sizeof (*ptrlock) > sizeof (int))
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    intptr += (sizeof (*ptrlock) / sizeof (int)) - 1;
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#endif
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  do
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    do_wait (intptr, 2);
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  while (*intptr == 2);
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  __asm volatile ("" : : : "memory");
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  return *ptrlock;
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}
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void
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gomp_ptrlock_set_slow (gomp_ptrlock_t *ptrlock)
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{
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  int *intptr;
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  __asm volatile ("" : "=r" (intptr) : "0" (ptrlock));
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#if __BYTE_ORDER == __BIG_ENDIAN
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  if (sizeof (*ptrlock) > sizeof (int))
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    intptr += (sizeof (*ptrlock) / sizeof (int)) - 1;
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#endif
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  futex_wake (intptr, INT_MAX);
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}

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