]>
Commit | Line | Data |
---|---|---|
85ec4feb | 1 | /* Copyright (C) 2012-2018 Free Software Foundation, Inc. |
48310492 RH |
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)); |