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 extern void clear_bit(int nr, volatile void * addr);
28 extern void change_bit(int nr, volatile void * addr);
29
30 extern int test_and_set_bit(int nr, volatile void * addr);
31 extern int test_and_clear_bit(int nr, volatile void * addr);
32 extern int test_and_change_bit(int nr, volatile void * addr);
33 extern int find_first_zero_bit(void * addr, unsigned size);
34 extern int find_next_zero_bit(void * addr, int size, int offset);
35
36 /*
37 * This routine doesn't need to be atomic.
38 */
39 extern __inline__ int test_bit(int nr, const void * addr)
40 {
41 return ((unsigned char *) addr)[nr >> 3] & (1U << (nr & 7));
42 }
43
44 /*
45 * ffz = Find First Zero in word. Undefined if no zero exists,
46 * so code should check against ~0UL first..
47 */
48 extern __inline__ unsigned long ffz(unsigned long word)
49 {
50 int k;
51
52 word = ~word;
53 k = 31;
54 if (word & 0x0000ffff) { k -= 16; word <<= 16; }
55 if (word & 0x00ff0000) { k -= 8; word <<= 8; }
56 if (word & 0x0f000000) { k -= 4; word <<= 4; }
57 if (word & 0x30000000) { k -= 2; word <<= 2; }
58 if (word & 0x40000000) { k -= 1; }
59 return k;
60 }
61
62 /*
63 * ffs: find first bit set. This is defined the same way as
64 * the libc and compiler builtin ffs routines, therefore
65 * differs in spirit from the above ffz (man ffs).
66 */
67
68 #define ffs(x) generic_ffs(x)
69
70 /*
71 * hweightN: returns the hamming weight (i.e. the number
72 * of bits set) of a N-bit word
73 */
74
75 #define hweight32(x) generic_hweight32(x)
76 #define hweight16(x) generic_hweight16(x)
77 #define hweight8(x) generic_hweight8(x)
78
79 #define ext2_set_bit test_and_set_bit
80 #define ext2_clear_bit test_and_clear_bit
81 #define ext2_test_bit test_bit
82 #define ext2_find_first_zero_bit find_first_zero_bit
83 #define ext2_find_next_zero_bit find_next_zero_bit
84
85 /* Bitmap functions for the minix filesystem. */
86 #define minix_test_and_set_bit(nr,addr) test_and_set_bit(nr,addr)
87 #define minix_set_bit(nr,addr) set_bit(nr,addr)
88 #define minix_test_and_clear_bit(nr,addr) test_and_clear_bit(nr,addr)
89 #define minix_test_bit(nr,addr) test_bit(nr,addr)
90 #define minix_find_first_zero_bit(addr,size) find_first_zero_bit(addr,size)
91
92 #endif /* __KERNEL__ */
93
94 #endif /* _ARM_BITOPS_H */
95
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