mirror of https://github.com/PCSX2/pcsx2.git
99 lines
3.2 KiB
C
99 lines
3.2 KiB
C
/*
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* pthread_barrier_wait.c
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*
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* Description:
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* This translation unit implements barrier primitives.
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*
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* --------------------------------------------------------------------------
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*
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* Pthreads-win32 - POSIX Threads Library for Win32
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* Copyright(C) 1998 John E. Bossom
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* Copyright(C) 1999,2005 Pthreads-win32 contributors
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*
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* Contact Email: rpj@callisto.canberra.edu.au
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*
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* The current list of contributors is contained
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* in the file CONTRIBUTORS included with the source
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* code distribution. The list can also be seen at the
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* following World Wide Web location:
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* http://sources.redhat.com/pthreads-win32/contributors.html
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library in the file COPYING.LIB;
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* if not, write to the Free Software Foundation, Inc.,
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* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
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*/
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#include "ptw32pch.h"
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int
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pthread_barrier_wait (pthread_barrier_t * barrier)
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{
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int result;
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int step;
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pthread_barrier_t b;
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if (barrier == NULL || *barrier == (pthread_barrier_t) PTW32_OBJECT_INVALID)
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{
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return EINVAL;
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}
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b = *barrier;
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step = b->iStep;
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if (0 == InterlockedDecrement ((long *) &(b->nCurrentBarrierHeight)))
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{
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/* Must be done before posting the semaphore. */
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b->nCurrentBarrierHeight = b->nInitialBarrierHeight;
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/*
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* There is no race condition between the semaphore wait and post
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* because we are using two alternating semas and all threads have
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* entered barrier_wait and checked nCurrentBarrierHeight before this
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* barrier's sema can be posted. Any threads that have not quite
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* entered sem_wait below when the multiple_post has completed
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* will nevertheless continue through the semaphore (barrier)
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* and will not be left stranded.
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*/
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result = (b->nInitialBarrierHeight > 1
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? sem_post_multiple (&(b->semBarrierBreeched[step]),
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b->nInitialBarrierHeight - 1) : 0);
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}
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else
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{
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/*
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* Use the non-cancelable version of sem_wait().
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*/
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result = ptw32_semwait (&(b->semBarrierBreeched[step]));
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}
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/*
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* The first thread across will be the PTHREAD_BARRIER_SERIAL_THREAD.
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* This also sets up the alternate semaphore as the next barrier.
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*/
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if (0 == result)
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{
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result = ((PTW32_INTERLOCKED_LONG) step ==
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PTW32_INTERLOCKED_COMPARE_EXCHANGE ((PTW32_INTERLOCKED_LPLONG)
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& (b->iStep),
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(PTW32_INTERLOCKED_LONG)
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(1L - step),
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(PTW32_INTERLOCKED_LONG)
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step) ?
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PTHREAD_BARRIER_SERIAL_THREAD : 0);
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}
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return (result);
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}
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