1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
|
// Low-level functions for atomic operations: m68k version -*- C++ -*-
// Copyright (C) 2001-2015 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library. This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
// <http://www.gnu.org/licenses/>.
#include <ext/atomicity.h>
namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
#if ( defined(__mc68020__) || defined(__mc68030__) \
|| defined(__mc68040__) || defined(__mc68060__) ) \
&& !defined(__mcpu32__)
// These variants support compare-and-swap.
_Atomic_word
__attribute__ ((__unused__))
__exchange_and_add(volatile _Atomic_word* __mem, int __val) throw ()
{
register _Atomic_word __result = *__mem;
register _Atomic_word __temp;
__asm__ __volatile__ ("1: move%.l %0,%1\n\t"
"add%.l %3,%1\n\t"
"cas%.l %0,%1,%2\n\t"
"jne 1b"
: "=d" (__result), "=&d" (__temp), "=m" (*__mem)
: "d" (__val), "0" (__result), "m" (*__mem));
return __result;
}
#elif defined(__rtems__)
// TAS/JBNE is unsafe on systems with strict priority-based scheduling.
// Disable interrupts, which we can do only from supervisor mode.
_Atomic_word
__attribute__ ((__unused__))
__exchange_and_add(volatile _Atomic_word* __mem, int __val) throw ()
{
_Atomic_word __result;
short __level, __tmpsr;
__asm__ __volatile__ ("move%.w %%sr,%0\n\tor%.l %0,%1\n\tmove%.w %1,%%sr"
: "=d"(__level), "=d"(__tmpsr) : "1"(0x700));
__result = *__mem;
*__mem = __result + __val;
__asm__ __volatile__ ("move%.w %0,%%sr" : : "d"(__level));
return __result;
}
#else
template<int __inst>
struct _Atomicity_lock
{
static volatile unsigned char _S_atomicity_lock;
};
template<int __inst>
volatile unsigned char _Atomicity_lock<__inst>::_S_atomicity_lock = 0;
template volatile unsigned char _Atomicity_lock<0>::_S_atomicity_lock;
_Atomic_word
__attribute__ ((__unused__))
__exchange_and_add(volatile _Atomic_word* __mem, int __val) throw ()
{
_Atomic_word __result;
// bset with no immediate addressing (not SMP-safe)
#if defined(__mcfisaa__) || defined(__mcfisaaplus__)
__asm__ __volatile__("1: bset.b #7,%0@\n\tjbne 1b"
: /* no outputs */
: "a"(&_Atomicity_lock<0>::_S_atomicity_lock)
: "cc", "memory");
// CPU32 and CF ISAs B & C support test-and-set (SMP-safe).
#elif defined(__mcpu32__) || defined(__mcfisab__) || defined (__mcfisac__)
__asm__ __volatile__("1: tas %0\n\tjbne 1b"
: "+m"(_Atomicity_lock<0>::_S_atomicity_lock)
: /* none */
: "cc");
// Use bset with immediate addressing for 68000/68010 (not SMP-safe)
// NOTE: TAS is available on the 68000, but unsupported by some Amiga
// memory controllers.
#else
__asm__ __volatile__("1: bset.b #7,%0\n\tjbne 1b"
: "+m"(_Atomicity_lock<0>::_S_atomicity_lock)
: /* none */
: "cc");
#endif
__result = *__mem;
*__mem = __result + __val;
_Atomicity_lock<0>::_S_atomicity_lock = 0;
return __result;
}
#endif /* TAS / BSET */
void
__attribute__ ((__unused__))
__atomic_add(volatile _Atomic_word* __mem, int __val) throw ()
{
// Careful: using add.l with a memory destination is not
// architecturally guaranteed to be atomic.
__exchange_and_add(__mem, __val);
}
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace
|
