59 lines
2.0 KiB
C
59 lines
2.0 KiB
C
/* Copyright (C) 2015-2021 Free Software Foundation, Inc.
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Contributed by Mentor Embedded.
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This file is part of the GNU Offloading and Multi Processing Library
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(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 the AMD GCN implementation of doacross spinning. */
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#ifndef GOMP_DOACROSS_H
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#define GOMP_DOACROSS_H 1
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#include "libgomp.h"
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static inline int
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cpu_relax (void)
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{
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/* This can be implemented as just a memory barrier, but a sleep seems
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like it should allow the wavefront to yield (maybe?)
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Use the shortest possible sleep time of 1*64 cycles. */
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asm volatile ("s_sleep\t1" ::: "memory");
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return 0;
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}
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static inline void doacross_spin (unsigned long *addr, unsigned long expected,
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unsigned long cur)
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{
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/* Prevent compiler from optimizing based on bounds of containing object. */
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asm ("" : "+r" (addr));
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do
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{
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/* An alternative implementation might use s_setprio to lower the
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priority temporarily, and then restore it after. */
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int i = cpu_relax ();
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cur = addr[i];
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}
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while (cur <= expected);
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}
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#endif /* GOMP_DOACROSS_H */
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