1 /*
2 * Copyright 1995, Russell King.
3 * Various bits and pieces copyrights include:
4 * Linus Torvalds (test_bit).
5 *
6 * bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1).
7 *
8 * Please note that the code in this file should never be included
9 * from user space. Many of these are not implemented in assembler
10 * since they would be too costly. Also, they require priviledged
11 * instructions (which are not available from user mode) to ensure
12 * that they are atomic.
13 */
14
15 #ifndef __ASM_ARM_BITOPS_H
16 #define __ASM_ARM_BITOPS_H
17
18 #ifdef __KERNEL__
19
20 #define smp_mb__before_clear_bit() do { } while (0)
21 #define smp_mb__after_clear_bit() do { } while (0)
22
23 /*
24 * Function prototypes to keep gcc -Wall happy.
25 */
26 extern void set_bit(int nr, volatile void * addr);
27
__set_bit(int nr,volatile void * addr)28 static inline void __set_bit(int nr, volatile void *addr)
29 {
30 ((unsigned char *) addr)[nr >> 3] |= (1U << (nr & 7));
31 }
32
33 extern void clear_bit(int nr, volatile void * addr);
34
__clear_bit(int nr,volatile void * addr)35 static inline void __clear_bit(int nr, volatile void *addr)
36 {
37 ((unsigned char *) addr)[nr >> 3] &= ~(1U << (nr & 7));
38 }
39
40 extern void change_bit(int nr, volatile void * addr);
41
__change_bit(int nr,volatile void * addr)42 static inline void __change_bit(int nr, volatile void *addr)
43 {
44 ((unsigned char *) addr)[nr >> 3] ^= (1U << (nr & 7));
45 }
46
47 extern int test_and_set_bit(int nr, volatile void * addr);
48
__test_and_set_bit(int nr,volatile void * addr)49 static inline int __test_and_set_bit(int nr, volatile void *addr)
50 {
51 unsigned int mask = 1 << (nr & 7);
52 unsigned int oldval;
53
54 oldval = ((unsigned char *) addr)[nr >> 3];
55 ((unsigned char *) addr)[nr >> 3] = oldval | mask;
56 return oldval & mask;
57 }
58
59 extern int test_and_clear_bit(int nr, volatile void * addr);
60
__test_and_clear_bit(int nr,volatile void * addr)61 static inline int __test_and_clear_bit(int nr, volatile void *addr)
62 {
63 unsigned int mask = 1 << (nr & 7);
64 unsigned int oldval;
65
66 oldval = ((unsigned char *) addr)[nr >> 3];
67 ((unsigned char *) addr)[nr >> 3] = oldval & ~mask;
68 return oldval & mask;
69 }
70
71 extern int test_and_change_bit(int nr, volatile void * addr);
72
__test_and_change_bit(int nr,volatile void * addr)73 static inline int __test_and_change_bit(int nr, volatile void *addr)
74 {
75 unsigned int mask = 1 << (nr & 7);
76 unsigned int oldval;
77
78 oldval = ((unsigned char *) addr)[nr >> 3];
79 ((unsigned char *) addr)[nr >> 3] = oldval ^ mask;
80 return oldval & mask;
81 }
82
83 extern int find_first_zero_bit(void * addr, unsigned size);
84 extern int find_next_zero_bit(void * addr, int size, int offset);
85
86 /*
87 * This routine doesn't need to be atomic.
88 */
test_bit(int nr,const void * addr)89 static inline int test_bit(int nr, const void * addr)
90 {
91 return (((unsigned char *) addr)[nr >> 3] >> (nr & 7)) & 1;
92 }
93
94 /*
95 * ffz = Find First Zero in word. Undefined if no zero exists,
96 * so code should check against ~0UL first..
97 */
ffz(unsigned long word)98 static inline unsigned long ffz(unsigned long word)
99 {
100 int k;
101
102 word = ~word;
103 k = 31;
104 if (word & 0x0000ffff) { k -= 16; word <<= 16; }
105 if (word & 0x00ff0000) { k -= 8; word <<= 8; }
106 if (word & 0x0f000000) { k -= 4; word <<= 4; }
107 if (word & 0x30000000) { k -= 2; word <<= 2; }
108 if (word & 0x40000000) { k -= 1; }
109 return k;
110 }
111
112 /*
113 * ffs: find first bit set. This is defined the same way as
114 * the libc and compiler builtin ffs routines, therefore
115 * differs in spirit from the above ffz (man ffs).
116 */
117
118 #define ffs(x) generic_ffs(x)
119
120 /*
121 * hweightN: returns the hamming weight (i.e. the number
122 * of bits set) of a N-bit word
123 */
124
125 #define hweight32(x) generic_hweight32(x)
126 #define hweight16(x) generic_hweight16(x)
127 #define hweight8(x) generic_hweight8(x)
128
129 #define ext2_set_bit test_and_set_bit
130 #define ext2_clear_bit test_and_clear_bit
131 #define ext2_test_bit test_bit
132 #define ext2_find_first_zero_bit find_first_zero_bit
133 #define ext2_find_next_zero_bit find_next_zero_bit
134
135 /* Bitmap functions for the minix filesystem. */
136 #define minix_test_and_set_bit(nr,addr) test_and_set_bit(nr,addr)
137 #define minix_set_bit(nr,addr) set_bit(nr,addr)
138 #define minix_test_and_clear_bit(nr,addr) test_and_clear_bit(nr,addr)
139 #define minix_test_bit(nr,addr) test_bit(nr,addr)
140 #define minix_find_first_zero_bit(addr,size) find_first_zero_bit(addr,size)
141
142 #endif /* __KERNEL__ */
143
144 #endif /* _ARM_BITOPS_H */
145