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/*
* Copyright 2011-2015 Samy Al Bahra.
* Copyright 2011 David Joseph.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <ck_barrier.h>
#include <ck_pr.h>
void
ck_barrier_centralized(struct ck_barrier_centralized *barrier,
struct ck_barrier_centralized_state *state,
unsigned int n_threads)
{
unsigned int sense, value;
/*
* Every execution context has a sense associated with it.
* This sense is reversed when the barrier is entered. Every
* thread will spin on the global sense until the last thread
* reverses it.
*/
sense = state->sense = ~state->sense;
value = ck_pr_faa_uint(&barrier->value, 1);
if (value == n_threads - 1) {
ck_pr_store_uint(&barrier->value, 0);
ck_pr_fence_memory();
ck_pr_store_uint(&barrier->sense, sense);
return;
}
ck_pr_fence_atomic_load();
while (sense != ck_pr_load_uint(&barrier->sense))
ck_pr_stall();
ck_pr_fence_acquire();
return;
}
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