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acae253e | 1 | // Low-level functions for atomic operations: m68k version -*- C++ -*- |
b8f73826 | 2 | |
748086b7 | 3 | // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2009 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 | |
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27 | _GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx) |
28 | ||
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29 | #if ( defined(__mc68020__) || defined(__mc68030__) \ |
30 | || defined(__mc68040__) || defined(__mc68060__) ) \ | |
31 | && !defined(__mcpu32__) | |
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32 | // These variants support compare-and-swap. |
33 | _Atomic_word | |
34 | __attribute__ ((__unused__)) | |
35 | __exchange_and_add(volatile _Atomic_word* __mem, int __val) | |
36 | { | |
37 | register _Atomic_word __result = *__mem; | |
38 | register _Atomic_word __temp; | |
39 | __asm__ __volatile__ ("1: move%.l %0,%1\n\t" | |
40 | "add%.l %3,%1\n\t" | |
41 | "cas%.l %0,%1,%2\n\t" | |
42 | "jne 1b" | |
43 | : "=d" (__result), "=&d" (__temp), "=m" (*__mem) | |
44 | : "d" (__val), "0" (__result), "m" (*__mem)); | |
45 | return __result; | |
46 | } | |
b8f73826 | 47 | |
0b46224d | 48 | #elif defined(__rtems__) |
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49 | // TAS/JBNE is unsafe on systems with strict priority-based scheduling. |
50 | // Disable interrupts, which we can do only from supervisor mode. | |
51 | _Atomic_word | |
52 | __attribute__ ((__unused__)) | |
53 | __exchange_and_add(volatile _Atomic_word* __mem, int __val) | |
54 | { | |
55 | _Atomic_word __result; | |
56 | short __level, __tmpsr; | |
57 | __asm__ __volatile__ ("move%.w %%sr,%0\n\tor%.l %0,%1\n\tmove%.w %1,%%sr" | |
58 | : "=d"(__level), "=d"(__tmpsr) : "1"(0x700)); | |
59 | ||
60 | __result = *__mem; | |
61 | *__mem = __result + __val; | |
62 | __asm__ __volatile__ ("move%.w %0,%%sr" : : "d"(__level)); | |
63 | ||
64 | return __result; | |
65 | } | |
0b46224d | 66 | |
4e9ebd4b | 67 | #else |
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68 | |
69 | template<int __inst> | |
00d04db6 | 70 | struct _Atomicity_lock |
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71 | { |
72 | static volatile unsigned char _S_atomicity_lock; | |
73 | }; | |
74 | ||
75 | template<int __inst> | |
00d04db6 | 76 | volatile unsigned char _Atomicity_lock<__inst>::_S_atomicity_lock = 0; |
2c5d0ae8 | 77 | |
00d04db6 | 78 | template volatile unsigned char _Atomicity_lock<0>::_S_atomicity_lock; |
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79 | |
80 | _Atomic_word | |
81 | __attribute__ ((__unused__)) | |
82 | __exchange_and_add(volatile _Atomic_word* __mem, int __val) | |
5ec3f566 | 83 | { |
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84 | _Atomic_word __result; |
85 | ||
86 | // bset with no immediate addressing (not SMP-safe) | |
19caedae | 87 | #if defined(__mcfisaa__) || defined(__mcfisaaplus__) |
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88 | __asm__ __volatile__("1: bset.b #7,%0@\n\tjbne 1b" |
89 | : /* no outputs */ | |
00d04db6 | 90 | : "a"(&_Atomicity_lock<0>::_S_atomicity_lock) |
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91 | : "cc", "memory"); |
92 | ||
19caedae NS |
93 | // CPU32 and CF ISAs B & C support test-and-set (SMP-safe). |
94 | #elif defined(__mcpu32__) || defined(__mcfisab__) || defined (__mcfisac__) | |
2c5d0ae8 | 95 | __asm__ __volatile__("1: tas %0\n\tjbne 1b" |
00d04db6 | 96 | : "+m"(_Atomicity_lock<0>::_S_atomicity_lock) |
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97 | : /* none */ |
98 | : "cc"); | |
99 | ||
100 | // Use bset with immediate addressing for 68000/68010 (not SMP-safe) | |
101 | // NOTE: TAS is available on the 68000, but unsupported by some Amiga | |
102 | // memory controllers. | |
068c84e3 | 103 | #else |
2c5d0ae8 | 104 | __asm__ __volatile__("1: bset.b #7,%0\n\tjbne 1b" |
00d04db6 | 105 | : "+m"(_Atomicity_lock<0>::_S_atomicity_lock) |
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106 | : /* none */ |
107 | : "cc"); | |
4e9ebd4b | 108 | #endif |
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109 | |
110 | __result = *__mem; | |
111 | *__mem = __result + __val; | |
112 | ||
00d04db6 | 113 | _Atomicity_lock<0>::_S_atomicity_lock = 0; |
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114 | |
115 | return __result; | |
116 | } | |
117 | ||
4e9ebd4b | 118 | #endif /* TAS / BSET */ |
acae253e | 119 | |
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120 | void |
121 | __attribute__ ((__unused__)) | |
122 | __atomic_add(volatile _Atomic_word* __mem, int __val) | |
123 | { | |
124 | // Careful: using add.l with a memory destination is not | |
125 | // architecturally guaranteed to be atomic. | |
126 | __exchange_and_add(__mem, __val); | |
127 | } | |
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128 | |
129 | _GLIBCXX_END_NAMESPACE |