1*38fd1498Szrj /* Copyright (C) 2015-2018 Free Software Foundation, Inc.
2*38fd1498Szrj Contributed by Jakub Jelinek <jakub@redhat.com>.
3*38fd1498Szrj
4*38fd1498Szrj This file is part of the GNU Offloading and Multi Processing Library
5*38fd1498Szrj (libgomp).
6*38fd1498Szrj
7*38fd1498Szrj Libgomp is free software; you can redistribute it and/or modify it
8*38fd1498Szrj under the terms of the GNU General Public License as published by
9*38fd1498Szrj the Free Software Foundation; either version 3, or (at your option)
10*38fd1498Szrj any later version.
11*38fd1498Szrj
12*38fd1498Szrj Libgomp is distributed in the hope that it will be useful, but WITHOUT ANY
13*38fd1498Szrj WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
14*38fd1498Szrj FOR A PARTICULAR PURPOSE. See the GNU General Public License for
15*38fd1498Szrj more details.
16*38fd1498Szrj
17*38fd1498Szrj Under Section 7 of GPL version 3, you are granted additional
18*38fd1498Szrj permissions described in the GCC Runtime Library Exception, version
19*38fd1498Szrj 3.1, as published by the Free Software Foundation.
20*38fd1498Szrj
21*38fd1498Szrj You should have received a copy of the GNU General Public License and
22*38fd1498Szrj a copy of the GCC Runtime Library Exception along with this program;
23*38fd1498Szrj see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
24*38fd1498Szrj <http://www.gnu.org/licenses/>. */
25*38fd1498Szrj
26*38fd1498Szrj /* This is a generic implementation of doacross spinning. */
27*38fd1498Szrj
28*38fd1498Szrj #ifndef GOMP_DOACROSS_H
29*38fd1498Szrj #define GOMP_DOACROSS_H 1
30*38fd1498Szrj
31*38fd1498Szrj #include "libgomp.h"
32*38fd1498Szrj #include <errno.h>
33*38fd1498Szrj
34*38fd1498Szrj #ifdef HAVE_ATTRIBUTE_VISIBILITY
35*38fd1498Szrj # pragma GCC visibility push(hidden)
36*38fd1498Szrj #endif
37*38fd1498Szrj
38*38fd1498Szrj static inline void
cpu_relax(void)39*38fd1498Szrj cpu_relax (void)
40*38fd1498Szrj {
41*38fd1498Szrj __asm volatile ("" : : : "memory");
42*38fd1498Szrj }
43*38fd1498Szrj
doacross_spin(unsigned long * addr,unsigned long expected,unsigned long cur)44*38fd1498Szrj static inline void doacross_spin (unsigned long *addr, unsigned long expected,
45*38fd1498Szrj unsigned long cur)
46*38fd1498Szrj {
47*38fd1498Szrj /* FIXME: back off depending on how large expected - cur is. */
48*38fd1498Szrj do
49*38fd1498Szrj {
50*38fd1498Szrj cpu_relax ();
51*38fd1498Szrj cur = __atomic_load_n (addr, MEMMODEL_RELAXED);
52*38fd1498Szrj if (expected < cur)
53*38fd1498Szrj return;
54*38fd1498Szrj }
55*38fd1498Szrj while (1);
56*38fd1498Szrj }
57*38fd1498Szrj
58*38fd1498Szrj #ifdef HAVE_ATTRIBUTE_VISIBILITY
59*38fd1498Szrj # pragma GCC visibility pop
60*38fd1498Szrj #endif
61*38fd1498Szrj
62*38fd1498Szrj #endif /* GOMP_DOACROSS_H */
63