Mercurial > hg > CbC > CbC_gcc
comparison libatomic/store_n.c @ 111:04ced10e8804
gcc 7
author | kono |
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date | Fri, 27 Oct 2017 22:46:09 +0900 |
parents | |
children | 84e7813d76e9 |
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68:561a7518be6b | 111:04ced10e8804 |
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1 /* Copyright (C) 2012-2017 Free Software Foundation, Inc. | |
2 Contributed by Richard Henderson <rth@redhat.com>. | |
3 | |
4 This file is part of the GNU Atomic Library (libatomic). | |
5 | |
6 Libatomic is free software; you can redistribute it and/or modify it | |
7 under the terms of the GNU General Public License as published by | |
8 the Free Software Foundation; either version 3 of the License, or | |
9 (at your option) any later version. | |
10 | |
11 Libatomic is distributed in the hope that it will be useful, but WITHOUT ANY | |
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS | |
13 FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
14 more details. | |
15 | |
16 Under Section 7 of GPL version 3, you are granted additional | |
17 permissions described in the GCC Runtime Library Exception, version | |
18 3.1, as published by the Free Software Foundation. | |
19 | |
20 You should have received a copy of the GNU General Public License and | |
21 a copy of the GCC Runtime Library Exception along with this program; | |
22 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see | |
23 <http://www.gnu.org/licenses/>. */ | |
24 | |
25 #include "libatomic_i.h" | |
26 | |
27 | |
28 /* If we support the builtin, just use it. */ | |
29 #if !DONE && SIZE(HAVE_ATOMIC_LDST) | |
30 void | |
31 SIZE(libat_store) (UTYPE *mptr, UTYPE newval, int smodel) | |
32 { | |
33 if (maybe_specialcase_relaxed(smodel)) | |
34 __atomic_store_n (mptr, newval, __ATOMIC_RELAXED); | |
35 else if (maybe_specialcase_acqrel(smodel)) | |
36 /* Note that ACQ and ACQ_REL are not valid for store. */ | |
37 __atomic_store_n (mptr, newval, __ATOMIC_RELEASE); | |
38 else | |
39 __atomic_store_n (mptr, newval, __ATOMIC_SEQ_CST); | |
40 } | |
41 | |
42 #define DONE 1 | |
43 #endif /* HAVE_ATOMIC_STORE */ | |
44 | |
45 /* If we have compare-and-swap, use it perform the store. */ | |
46 #if !DONE && defined(atomic_compare_exchange_n) | |
47 void | |
48 SIZE(libat_store) (UTYPE *mptr, UTYPE newval, int smodel) | |
49 { | |
50 UTYPE oldval; | |
51 | |
52 pre_barrier (smodel); | |
53 | |
54 oldval = *mptr; | |
55 while (!atomic_compare_exchange_n (mptr, &oldval, newval, true, | |
56 __ATOMIC_RELAXED, __ATOMIC_RELAXED)) | |
57 continue; | |
58 | |
59 post_barrier (smodel); | |
60 } | |
61 | |
62 #define DONE 1 | |
63 #endif /* atomic_compare_exchange_n */ | |
64 | |
65 | |
66 /* If this type is smaller than word-sized, fall back to a word-sized | |
67 compare-and-swap loop. */ | |
68 #if !DONE && N < WORDSIZE && defined(atomic_compare_exchange_w) | |
69 void | |
70 SIZE(libat_store) (UTYPE *mptr, UTYPE newval, int smodel) | |
71 { | |
72 UWORD mask, shift, woldval, wnewval, t, *wptr; | |
73 | |
74 pre_barrier (smodel); | |
75 | |
76 wptr = (UWORD *)((uintptr_t)mptr & -WORDSIZE); | |
77 shift = (((uintptr_t)mptr % WORDSIZE) * CHAR_BIT) ^ SIZE(INVERT_MASK); | |
78 mask = SIZE(MASK) << shift; | |
79 | |
80 wnewval = (UWORD)newval << shift; | |
81 woldval = __atomic_load_n (wptr, __ATOMIC_RELAXED); | |
82 do | |
83 { | |
84 t = (woldval & ~mask) | wnewval; | |
85 } | |
86 while (!atomic_compare_exchange_w (wptr, &woldval, t)); | |
87 | |
88 post_barrier (smodel); | |
89 } | |
90 | |
91 #define DONE 1 | |
92 #endif /* N < WORDSIZE && atomic_compare_exchange_w */ | |
93 | |
94 | |
95 /* Otherwise, fall back to some sort of protection mechanism. */ | |
96 #if !DONE | |
97 void | |
98 SIZE(libat_store) (UTYPE *mptr, UTYPE newval, int smodel) | |
99 { | |
100 UWORD magic; | |
101 | |
102 pre_seq_barrier (smodel); | |
103 magic = protect_start (mptr); | |
104 | |
105 *mptr = newval; | |
106 | |
107 protect_end (mptr, magic); | |
108 post_seq_barrier (smodel); | |
109 } | |
110 #endif | |
111 | |
112 EXPORT_ALIAS (SIZE(store)); |