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8d9254fc | 1 | /* Copyright (C) 2012-2020 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 | /* This file is included multiple times with required defines: | |
29 | NAME the name of the operation that we're implementing; | |
30 | OP a two-operand functional macro the implements the operation. | |
31 | */ | |
32 | ||
33 | ||
34 | /* If we support the builtin, just use it. */ | |
35 | #if !DONE && SIZE(HAVE_ATOMIC_FETCH_OP) | |
36 | UTYPE | |
37 | SIZE(C2(libat_fetch_,NAME)) (UTYPE *mptr, UTYPE opval, int smodel) | |
38 | { | |
39 | if (maybe_specialcase_relaxed(smodel)) | |
40 | return C2(__atomic_fetch_,NAME) (mptr, opval, __ATOMIC_RELAXED); | |
41 | else if (maybe_specialcase_acqrel(smodel)) | |
42 | return C2(__atomic_fetch_,NAME) (mptr, opval, __ATOMIC_ACQ_REL); | |
43 | else | |
44 | return C2(__atomic_fetch_,NAME) (mptr, opval, __ATOMIC_SEQ_CST); | |
45 | } | |
46 | ||
47 | UTYPE | |
48 | SIZE(C3(libat_,NAME,_fetch)) (UTYPE *mptr, UTYPE opval, int smodel) | |
49 | { | |
50 | if (maybe_specialcase_relaxed(smodel)) | |
51 | return C3(__atomic_,NAME,_fetch) (mptr, opval, __ATOMIC_RELAXED); | |
52 | else if (maybe_specialcase_acqrel(smodel)) | |
53 | return C3(__atomic_,NAME,_fetch) (mptr, opval, __ATOMIC_ACQ_REL); | |
54 | else | |
55 | return C3(__atomic_,NAME,_fetch) (mptr, opval, __ATOMIC_SEQ_CST); | |
56 | } | |
57 | ||
58 | #define DONE 1 | |
59 | #endif /* HAVE_ATOMIC_FETCH_OP */ | |
60 | ||
61 | ||
62 | #if !DONE && defined(atomic_compare_exchange_n) | |
63 | UTYPE | |
64 | SIZE(C2(libat_fetch_,NAME)) (UTYPE *mptr, UTYPE opval, int smodel) | |
65 | { | |
66 | UTYPE oldval, t; | |
67 | ||
68 | pre_barrier (smodel); | |
69 | ||
70 | oldval = *mptr; | |
71 | do | |
72 | { | |
73 | t = OP(oldval, opval); | |
74 | } | |
75 | while (!atomic_compare_exchange_n (mptr, &oldval, t, true, | |
76 | __ATOMIC_RELAXED, __ATOMIC_RELAXED)); | |
77 | ||
78 | post_barrier (smodel); | |
79 | return oldval; | |
80 | } | |
81 | ||
82 | UTYPE | |
83 | SIZE(C3(libat_,NAME,_fetch)) (UTYPE *mptr, UTYPE opval, int smodel) | |
84 | { | |
85 | UTYPE oldval, t; | |
86 | ||
87 | pre_barrier (smodel); | |
88 | ||
89 | oldval = *mptr; | |
90 | do | |
91 | { | |
92 | t = OP(oldval, opval); | |
93 | } | |
94 | while (!atomic_compare_exchange_n (mptr, &oldval, t, true, | |
95 | __ATOMIC_RELAXED, __ATOMIC_RELAXED)); | |
96 | ||
97 | post_barrier (smodel); | |
98 | return t; | |
99 | } | |
100 | ||
101 | #define DONE 1 | |
102 | #endif /* atomic_compare_exchange_n */ | |
103 | ||
104 | ||
105 | /* If this type is no larger than word-sized, fall back to a word-sized | |
106 | compare-and-swap loop. */ | |
107 | #if !DONE && N < WORDSIZE && defined(atomic_compare_exchange_w) | |
108 | UTYPE | |
109 | SIZE(C2(libat_fetch_,NAME)) (UTYPE *mptr, UTYPE opval, int smodel) | |
110 | { | |
111 | UWORD mask, shift, woldval, wopval, t, *wptr; | |
112 | ||
113 | pre_barrier (smodel); | |
114 | ||
122a5d60 AW |
115 | wptr = (UWORD *)((uintptr_t)mptr & -WORDSIZE); |
116 | shift = (((uintptr_t)mptr % WORDSIZE) * CHAR_BIT) ^ SIZE(INVERT_MASK); | |
117 | mask = SIZE(MASK) << shift; | |
48310492 RH |
118 | |
119 | wopval = (UWORD)opval << shift; | |
120 | woldval = __atomic_load_n (wptr, __ATOMIC_RELAXED); | |
121 | do | |
122 | { | |
123 | t = (woldval & ~mask) | (OP(woldval, wopval) & mask); | |
124 | } | |
125 | while (!atomic_compare_exchange_w (wptr, &woldval, t, true, | |
126 | __ATOMIC_RELAXED, __ATOMIC_RELAXED)); | |
127 | ||
128 | post_barrier (smodel); | |
129 | return woldval >> shift; | |
130 | } | |
131 | ||
132 | UTYPE | |
133 | SIZE(C3(libat_,NAME,_fetch)) (UTYPE *mptr, UTYPE opval, int smodel) | |
134 | { | |
135 | UWORD mask, shift, woldval, wopval, t, *wptr; | |
136 | ||
137 | pre_barrier (smodel); | |
138 | ||
122a5d60 AW |
139 | wptr = (UWORD *)((uintptr_t)mptr & -WORDSIZE); |
140 | shift = (((uintptr_t)mptr % WORDSIZE) * CHAR_BIT) ^ SIZE(INVERT_MASK); | |
141 | mask = SIZE(MASK) << shift; | |
48310492 RH |
142 | |
143 | wopval = (UWORD)opval << shift; | |
144 | woldval = __atomic_load_n (wptr, __ATOMIC_RELAXED); | |
145 | do | |
146 | { | |
147 | t = (woldval & ~mask) | (OP(woldval, wopval) & mask); | |
148 | } | |
149 | while (!atomic_compare_exchange_w (wptr, &woldval, t, true, | |
150 | __ATOMIC_RELAXED, __ATOMIC_RELAXED)); | |
151 | ||
152 | post_barrier (smodel); | |
153 | return t >> shift; | |
154 | } | |
155 | ||
156 | #define DONE 1 | |
157 | #endif /* atomic_compare_exchange_w */ | |
158 | ||
159 | ||
160 | /* Otherwise, fall back to some sort of protection mechanism. */ | |
161 | #if !DONE | |
162 | UTYPE | |
163 | SIZE(C2(libat_fetch_,NAME)) (UTYPE *mptr, UTYPE opval, int smodel UNUSED) | |
164 | { | |
165 | UTYPE ret; | |
166 | UWORD magic; | |
167 | ||
168 | pre_seq_barrier (smodel); | |
169 | magic = protect_start (mptr); | |
170 | ||
171 | ret = *mptr; | |
172 | *mptr = OP(ret, opval); | |
173 | ||
174 | protect_end (mptr, magic); | |
175 | post_seq_barrier (smodel); | |
176 | ||
177 | return ret; | |
178 | } | |
179 | ||
180 | UTYPE | |
181 | SIZE(C3(libat_,NAME,_fetch)) (UTYPE *mptr, UTYPE opval, int smodel UNUSED) | |
182 | { | |
183 | UTYPE ret; | |
184 | UWORD magic; | |
185 | ||
186 | pre_seq_barrier (smodel); | |
187 | magic = protect_start (mptr); | |
188 | ||
189 | ret = OP (*mptr, opval); | |
190 | *mptr = ret; | |
191 | ||
192 | protect_end (mptr, magic); | |
193 | post_seq_barrier (smodel); | |
194 | ||
195 | return ret; | |
196 | } | |
197 | #endif | |
198 | ||
199 | EXPORT_ALIAS (SIZE(C2(fetch_,NAME))); | |
200 | EXPORT_ALIAS (SIZE(C2(NAME,_fetch))); |