2 * Copyright 1995, Russell King.
3 * Various bits and pieces copyrights include:
4 * Linus Torvalds (test_bit).
6 * bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1).
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.
15 #ifndef __ASM_ARM_BITOPS_H
16 #define __ASM_ARM_BITOPS_H
20 #define smp_mb__before_clear_bit() do { } while (0)
21 #define smp_mb__after_clear_bit() do { } while (0)
24 * Function prototypes to keep gcc -Wall happy.
26 extern void set_bit(int nr, volatile void * addr);
28 static inline void __set_bit(int nr, volatile void *addr)
30 ((unsigned char *) addr)[nr >> 3] |= (1U << (nr & 7));
34 extern void clear_bit(int nr, volatile void * addr);
36 static inline void __clear_bit(int nr, volatile void *addr)
38 ((unsigned char *) addr)[nr >> 3] &= ~(1U << (nr & 7));
42 extern void change_bit(int nr, volatile void * addr);
44 static inline void __change_bit(int nr, volatile void *addr)
46 ((unsigned char *) addr)[nr >> 3] ^= (1U << (nr & 7));
49 extern int test_and_set_bit(int nr, volatile void * addr);
51 static inline int __test_and_set_bit(int nr, volatile void *addr)
53 unsigned int mask = 1 << (nr & 7);
56 oldval = ((unsigned char *) addr)[nr >> 3];
57 ((unsigned char *) addr)[nr >> 3] = oldval | mask;
61 extern int test_and_clear_bit(int nr, volatile void * addr);
63 static inline int __test_and_clear_bit(int nr, volatile void *addr)
65 unsigned int mask = 1 << (nr & 7);
68 oldval = ((unsigned char *) addr)[nr >> 3];
69 ((unsigned char *) addr)[nr >> 3] = oldval & ~mask;
73 extern int test_and_change_bit(int nr, volatile void * addr);
75 static inline int __test_and_change_bit(int nr, volatile void *addr)
77 unsigned int mask = 1 << (nr & 7);
80 oldval = ((unsigned char *) addr)[nr >> 3];
81 ((unsigned char *) addr)[nr >> 3] = oldval ^ mask;
85 extern int find_first_zero_bit(void * addr, unsigned size);
86 extern int find_next_zero_bit(void * addr, int size, int offset);
89 * This routine doesn't need to be atomic.
91 static inline int test_bit(int nr, const void * addr)
93 return ((unsigned char *) addr)[nr >> 3] & (1U << (nr & 7));
97 * ffz = Find First Zero in word. Undefined if no zero exists,
98 * so code should check against ~0UL first..
100 static inline unsigned long ffz(unsigned long word)
106 if (word & 0x0000ffff) { k -= 16; word <<= 16; }
107 if (word & 0x00ff0000) { k -= 8; word <<= 8; }
108 if (word & 0x0f000000) { k -= 4; word <<= 4; }
109 if (word & 0x30000000) { k -= 2; word <<= 2; }
110 if (word & 0x40000000) { k -= 1; }
115 * ffs: find first bit set. This is defined the same way as
116 * the libc and compiler builtin ffs routines, therefore
117 * differs in spirit from the above ffz (man ffs).
120 #define ffs(x) generic_ffs(x)
123 * hweightN: returns the hamming weight (i.e. the number
124 * of bits set) of a N-bit word
127 #define hweight32(x) generic_hweight32(x)
128 #define hweight16(x) generic_hweight16(x)
129 #define hweight8(x) generic_hweight8(x)
131 #define ext2_set_bit test_and_set_bit
132 #define ext2_clear_bit test_and_clear_bit
133 #define ext2_test_bit test_bit
134 #define ext2_find_first_zero_bit find_first_zero_bit
135 #define ext2_find_next_zero_bit find_next_zero_bit
137 /* Bitmap functions for the minix filesystem. */
138 #define minix_test_and_set_bit(nr,addr) test_and_set_bit(nr,addr)
139 #define minix_set_bit(nr,addr) set_bit(nr,addr)
140 #define minix_test_and_clear_bit(nr,addr) test_and_clear_bit(nr,addr)
141 #define minix_test_bit(nr,addr) test_bit(nr,addr)
142 #define minix_find_first_zero_bit(addr,size) find_first_zero_bit(addr,size)
144 #endif /* __KERNEL__ */
146 #endif /* _ARM_BITOPS_H */