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
|
/*
* Copyright (C) 2008 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/atomics.h>
#define FUTEX_SYSCALL 240
#define FUTEX_WAIT 0
#define FUTEX_WAKE 1
int __futex_wait(volatile void *ftx, int val)
{
int ret;
asm volatile (
"int $0x80;"
: "=a" (ret)
: "0" (FUTEX_SYSCALL),
"b" (ftx),
"c" (FUTEX_WAIT),
"d" (val),
"S" (0)
);
return ret;
}
int __futex_wake(volatile void *ftx, int count)
{
int ret;
asm volatile (
"int $0x80;"
: "=a" (ret)
: "0" (FUTEX_SYSCALL),
"b" (ftx),
"c" (FUTEX_WAKE),
"d" (count)
);
return ret;
}
int __atomic_cmpxchg(int old, int new, volatile int* addr) {
int xchg;
asm volatile (
"lock;"
"cmpxchg %%ecx, (%%edx);"
"setne %%al;"
: "=a" (xchg)
: "a" (old),
"c" (new),
"d" (addr)
);
return xchg;
}
int __atomic_swap(int new, volatile int* addr) {
int old;
asm volatile (
"lock;"
"xchg %%ecx, (%%edx);"
: "=c" (old)
: "c" (new),
"d" (addr)
);
return old;
}
int __atomic_dec(volatile int* addr) {
int old;
do {
old = *addr;
} while (atomic_cmpxchg(old, old-1, addr));
return old;
}
|
