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acae253e | 1 | // Low-level functions for atomic operations: m68k version -*- C++ -*- |
b8f73826 | 2 | |
7adcbafe | 3 | // Copyright (C) 2001-2022 Free Software Foundation, Inc. |
b8f73826 AS |
4 | // |
5 | // This file is part of the GNU ISO C++ Library. This library is free | |
6 | // software; you can redistribute it and/or modify it under the | |
7 | // terms of the GNU General Public License as published by the | |
748086b7 | 8 | // Free Software Foundation; either version 3, or (at your option) |
b8f73826 AS |
9 | // any later version. |
10 | ||
11 | // This library is distributed in the hope that it will be useful, | |
12 | // but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | // GNU General Public License for more details. | |
15 | ||
748086b7 JJ |
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/>. | |
b8f73826 | 24 | |
2e362c74 | 25 | #include <ext/atomicity.h> |
b8f73826 | 26 | |
12ffa228 BK |
27 | namespace __gnu_cxx _GLIBCXX_VISIBILITY(default) |
28 | { | |
29 | _GLIBCXX_BEGIN_NAMESPACE_VERSION | |
3cbc7af0 | 30 | |
4e9ebd4b BI |
31 | #if ( defined(__mc68020__) || defined(__mc68030__) \ |
32 | || defined(__mc68040__) || defined(__mc68060__) ) \ | |
33 | && !defined(__mcpu32__) | |
2c5d0ae8 | 34 | // These variants support compare-and-swap. |
f92ab29f | 35 | _Atomic_word |
2c5d0ae8 | 36 | __attribute__ ((__unused__)) |
09f2a1e4 | 37 | __exchange_and_add(volatile _Atomic_word* __mem, int __val) throw () |
2c5d0ae8 BK |
38 | { |
39 | register _Atomic_word __result = *__mem; | |
40 | register _Atomic_word __temp; | |
41 | __asm__ __volatile__ ("1: move%.l %0,%1\n\t" | |
42 | "add%.l %3,%1\n\t" | |
43 | "cas%.l %0,%1,%2\n\t" | |
44 | "jne 1b" | |
45 | : "=d" (__result), "=&d" (__temp), "=m" (*__mem) | |
46 | : "d" (__val), "0" (__result), "m" (*__mem)); | |
47 | return __result; | |
48 | } | |
b8f73826 | 49 | |
0b46224d | 50 | #elif defined(__rtems__) |
320c7be3 SH |
51 | // This code is only provided for reference. RTEMS uses now the atomic |
52 | // builtins and libatomic. See configure.host. | |
53 | // | |
2c5d0ae8 BK |
54 | // TAS/JBNE is unsafe on systems with strict priority-based scheduling. |
55 | // Disable interrupts, which we can do only from supervisor mode. | |
56 | _Atomic_word | |
57 | __attribute__ ((__unused__)) | |
09f2a1e4 | 58 | __exchange_and_add(volatile _Atomic_word* __mem, int __val) throw () |
2c5d0ae8 BK |
59 | { |
60 | _Atomic_word __result; | |
61 | short __level, __tmpsr; | |
62 | __asm__ __volatile__ ("move%.w %%sr,%0\n\tor%.l %0,%1\n\tmove%.w %1,%%sr" | |
63 | : "=d"(__level), "=d"(__tmpsr) : "1"(0x700)); | |
f92ab29f | 64 | |
2c5d0ae8 | 65 | __result = *__mem; |
f92ab29f | 66 | *__mem = __result + __val; |
2c5d0ae8 | 67 | __asm__ __volatile__ ("move%.w %0,%%sr" : : "d"(__level)); |
f92ab29f | 68 | |
2c5d0ae8 BK |
69 | return __result; |
70 | } | |
0b46224d | 71 | |
4e9ebd4b | 72 | #else |
f92ab29f | 73 | |
2c5d0ae8 | 74 | template<int __inst> |
00d04db6 | 75 | struct _Atomicity_lock |
2c5d0ae8 BK |
76 | { |
77 | static volatile unsigned char _S_atomicity_lock; | |
78 | }; | |
79 | ||
80 | template<int __inst> | |
00d04db6 | 81 | volatile unsigned char _Atomicity_lock<__inst>::_S_atomicity_lock = 0; |
f92ab29f | 82 | |
00d04db6 | 83 | template volatile unsigned char _Atomicity_lock<0>::_S_atomicity_lock; |
f92ab29f CG |
84 | |
85 | _Atomic_word | |
2c5d0ae8 | 86 | __attribute__ ((__unused__)) |
09f2a1e4 | 87 | __exchange_and_add(volatile _Atomic_word* __mem, int __val) throw () |
5ec3f566 | 88 | { |
2c5d0ae8 | 89 | _Atomic_word __result; |
f92ab29f | 90 | |
2c5d0ae8 | 91 | // bset with no immediate addressing (not SMP-safe) |
19caedae | 92 | #if defined(__mcfisaa__) || defined(__mcfisaaplus__) |
2c5d0ae8 BK |
93 | __asm__ __volatile__("1: bset.b #7,%0@\n\tjbne 1b" |
94 | : /* no outputs */ | |
00d04db6 | 95 | : "a"(&_Atomicity_lock<0>::_S_atomicity_lock) |
2c5d0ae8 | 96 | : "cc", "memory"); |
f92ab29f | 97 | |
19caedae NS |
98 | // CPU32 and CF ISAs B & C support test-and-set (SMP-safe). |
99 | #elif defined(__mcpu32__) || defined(__mcfisab__) || defined (__mcfisac__) | |
2c5d0ae8 | 100 | __asm__ __volatile__("1: tas %0\n\tjbne 1b" |
00d04db6 | 101 | : "+m"(_Atomicity_lock<0>::_S_atomicity_lock) |
2c5d0ae8 BK |
102 | : /* none */ |
103 | : "cc"); | |
f92ab29f | 104 | |
2c5d0ae8 BK |
105 | // Use bset with immediate addressing for 68000/68010 (not SMP-safe) |
106 | // NOTE: TAS is available on the 68000, but unsupported by some Amiga | |
107 | // memory controllers. | |
068c84e3 | 108 | #else |
2c5d0ae8 | 109 | __asm__ __volatile__("1: bset.b #7,%0\n\tjbne 1b" |
00d04db6 | 110 | : "+m"(_Atomicity_lock<0>::_S_atomicity_lock) |
2c5d0ae8 BK |
111 | : /* none */ |
112 | : "cc"); | |
4e9ebd4b | 113 | #endif |
f92ab29f | 114 | |
2c5d0ae8 BK |
115 | __result = *__mem; |
116 | *__mem = __result + __val; | |
f92ab29f | 117 | |
00d04db6 | 118 | _Atomicity_lock<0>::_S_atomicity_lock = 0; |
f92ab29f | 119 | |
2c5d0ae8 BK |
120 | return __result; |
121 | } | |
f92ab29f | 122 | |
4e9ebd4b | 123 | #endif /* TAS / BSET */ |
acae253e | 124 | |
2c5d0ae8 BK |
125 | void |
126 | __attribute__ ((__unused__)) | |
09f2a1e4 | 127 | __atomic_add(volatile _Atomic_word* __mem, int __val) throw () |
2c5d0ae8 BK |
128 | { |
129 | // Careful: using add.l with a memory destination is not | |
130 | // architecturally guaranteed to be atomic. | |
131 | __exchange_and_add(__mem, __val); | |
132 | } | |
3cbc7af0 | 133 | |
12ffa228 BK |
134 | _GLIBCXX_END_NAMESPACE_VERSION |
135 | } // namespace |