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1 | #ifndef _I386_SYNC_BITOPS_H |
2 | #define _I386_SYNC_BITOPS_H | |
3 | ||
4 | /* | |
5 | * Copyright 1992, Linus Torvalds. | |
6 | */ | |
7 | ||
8 | /* | |
9 | * These have to be done with inline assembly: that way the bit-setting | |
10 | * is guaranteed to be atomic. All bit operations return 0 if the bit | |
11 | * was cleared before the operation and != 0 if it was not. | |
12 | * | |
13 | * bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1). | |
14 | */ | |
15 | ||
16 | #define ADDR (*(volatile long *) addr) | |
17 | ||
18 | /** | |
19 | * sync_set_bit - Atomically set a bit in memory | |
20 | * @nr: the bit to set | |
21 | * @addr: the address to start counting from | |
22 | * | |
23 | * This function is atomic and may not be reordered. See __set_bit() | |
24 | * if you do not require the atomic guarantees. | |
25 | * | |
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26 | * Note that @nr may be almost arbitrarily large; this function is not |
27 | * restricted to acting on a single-word quantity. | |
28 | */ | |
29 | static inline void sync_set_bit(int nr, volatile unsigned long * addr) | |
30 | { | |
31 | __asm__ __volatile__("lock; btsl %1,%0" | |
32 | :"+m" (ADDR) | |
33 | :"Ir" (nr) | |
34 | : "memory"); | |
35 | } | |
36 | ||
37 | /** | |
38 | * sync_clear_bit - Clears a bit in memory | |
39 | * @nr: Bit to clear | |
40 | * @addr: Address to start counting from | |
41 | * | |
42 | * sync_clear_bit() is atomic and may not be reordered. However, it does | |
43 | * not contain a memory barrier, so if it is used for locking purposes, | |
44 | * you should call smp_mb__before_clear_bit() and/or smp_mb__after_clear_bit() | |
45 | * in order to ensure changes are visible on other processors. | |
46 | */ | |
47 | static inline void sync_clear_bit(int nr, volatile unsigned long * addr) | |
48 | { | |
49 | __asm__ __volatile__("lock; btrl %1,%0" | |
50 | :"+m" (ADDR) | |
51 | :"Ir" (nr) | |
52 | : "memory"); | |
53 | } | |
54 | ||
55 | /** | |
56 | * sync_change_bit - Toggle a bit in memory | |
57 | * @nr: Bit to change | |
58 | * @addr: Address to start counting from | |
59 | * | |
7800c0c3 | 60 | * sync_change_bit() is atomic and may not be reordered. |
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61 | * Note that @nr may be almost arbitrarily large; this function is not |
62 | * restricted to acting on a single-word quantity. | |
63 | */ | |
64 | static inline void sync_change_bit(int nr, volatile unsigned long * addr) | |
65 | { | |
66 | __asm__ __volatile__("lock; btcl %1,%0" | |
67 | :"+m" (ADDR) | |
68 | :"Ir" (nr) | |
69 | : "memory"); | |
70 | } | |
71 | ||
72 | /** | |
73 | * sync_test_and_set_bit - Set a bit and return its old value | |
74 | * @nr: Bit to set | |
75 | * @addr: Address to count from | |
76 | * | |
77 | * This operation is atomic and cannot be reordered. | |
027a8c7e CW |
78 | * It also implies a memory barrier. |
79 | */ | |
80 | static inline int sync_test_and_set_bit(int nr, volatile unsigned long * addr) | |
81 | { | |
82 | int oldbit; | |
83 | ||
84 | __asm__ __volatile__("lock; btsl %2,%1\n\tsbbl %0,%0" | |
85 | :"=r" (oldbit),"+m" (ADDR) | |
86 | :"Ir" (nr) : "memory"); | |
87 | return oldbit; | |
88 | } | |
89 | ||
90 | /** | |
91 | * sync_test_and_clear_bit - Clear a bit and return its old value | |
92 | * @nr: Bit to clear | |
93 | * @addr: Address to count from | |
94 | * | |
95 | * This operation is atomic and cannot be reordered. | |
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96 | * It also implies a memory barrier. |
97 | */ | |
98 | static inline int sync_test_and_clear_bit(int nr, volatile unsigned long * addr) | |
99 | { | |
100 | int oldbit; | |
101 | ||
102 | __asm__ __volatile__("lock; btrl %2,%1\n\tsbbl %0,%0" | |
103 | :"=r" (oldbit),"+m" (ADDR) | |
104 | :"Ir" (nr) : "memory"); | |
105 | return oldbit; | |
106 | } | |
107 | ||
108 | /** | |
109 | * sync_test_and_change_bit - Change a bit and return its old value | |
110 | * @nr: Bit to change | |
111 | * @addr: Address to count from | |
112 | * | |
113 | * This operation is atomic and cannot be reordered. | |
114 | * It also implies a memory barrier. | |
115 | */ | |
116 | static inline int sync_test_and_change_bit(int nr, volatile unsigned long* addr) | |
117 | { | |
118 | int oldbit; | |
119 | ||
120 | __asm__ __volatile__("lock; btcl %2,%1\n\tsbbl %0,%0" | |
121 | :"=r" (oldbit),"+m" (ADDR) | |
122 | :"Ir" (nr) : "memory"); | |
123 | return oldbit; | |
124 | } | |
125 | ||
f7d909d5 | 126 | #define sync_test_bit test_bit |
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127 | |
128 | #undef ADDR | |
129 | ||
130 | #endif /* _I386_SYNC_BITOPS_H */ |