1 #ifndef _ASM_GENERIC_BITOPS_NON_ATOMIC_H_
2 #define _ASM_GENERIC_BITOPS_NON_ATOMIC_H_
3 
4 #include <asm/types.h>
5 
6 /**
7  * __set_bit - Set a bit in memory
8  * @nr: the bit to set
9  * @addr: the address to start counting from
10  *
11  * Unlike set_bit(), this function is non-atomic and may be reordered.
12  * If it's called on the same region of memory simultaneously, the effect
13  * may be that only one operation succeeds.
14  */
15 static inline void __set_bit(int nr, volatile unsigned long *addr)
16 {
17 	unsigned long mask = BIT_MASK(nr);
18 	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
19 
20 	*p  |= mask;
21 }
22 
23 #define PLATFORM__SET_BIT
24 
25 static inline void __clear_bit(int nr, volatile unsigned long *addr)
26 {
27 	unsigned long mask = BIT_MASK(nr);
28 	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
29 
30 	*p &= ~mask;
31 }
32 
33 #define PLATFORM__CLEAR_BIT
34 
35 /**
36  * __change_bit - Toggle a bit in memory
37  * @nr: the bit to change
38  * @addr: the address to start counting from
39  *
40  * Unlike change_bit(), this function is non-atomic and may be reordered.
41  * If it's called on the same region of memory simultaneously, the effect
42  * may be that only one operation succeeds.
43  */
44 static inline void __change_bit(int nr, volatile unsigned long *addr)
45 {
46 	unsigned long mask = BIT_MASK(nr);
47 	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
48 
49 	*p ^= mask;
50 }
51 
52 /**
53  * __test_and_set_bit - Set a bit and return its old value
54  * @nr: Bit to set
55  * @addr: Address to count from
56  *
57  * This operation is non-atomic and can be reordered.
58  * If two examples of this operation race, one can appear to succeed
59  * but actually fail.  You must protect multiple accesses with a lock.
60  */
61 static inline int __test_and_set_bit(int nr, volatile unsigned long *addr)
62 {
63 	unsigned long mask = BIT_MASK(nr);
64 	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
65 	unsigned long old = *p;
66 
67 	*p = old | mask;
68 	return (old & mask) != 0;
69 }
70 
71 /**
72  * __test_and_clear_bit - Clear a bit and return its old value
73  * @nr: Bit to clear
74  * @addr: Address to count from
75  *
76  * This operation is non-atomic and can be reordered.
77  * If two examples of this operation race, one can appear to succeed
78  * but actually fail.  You must protect multiple accesses with a lock.
79  */
80 static inline int __test_and_clear_bit(int nr, volatile unsigned long *addr)
81 {
82 	unsigned long mask = BIT_MASK(nr);
83 	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
84 	unsigned long old = *p;
85 
86 	*p = old & ~mask;
87 	return (old & mask) != 0;
88 }
89 
90 /* WARNING: non atomic and it can be reordered! */
91 static inline int __test_and_change_bit(int nr,
92 					    volatile unsigned long *addr)
93 {
94 	unsigned long mask = BIT_MASK(nr);
95 	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
96 	unsigned long old = *p;
97 
98 	*p = old ^ mask;
99 	return (old & mask) != 0;
100 }
101 
102 /**
103  * test_bit - Determine whether a bit is set
104  * @nr: bit number to test
105  * @addr: Address to start counting from
106  */
107 static inline int test_bit(int nr, const volatile unsigned long *addr)
108 {
109 	return 1UL & (addr[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG-1)));
110 }
111 
112 #endif /* _ASM_GENERIC_BITOPS_NON_ATOMIC_H_ */
113