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 extern void clear_bit(int nr, volatile void * addr);
30 extern void change_bit(int nr, volatile void * addr);
32 static inline void __change_bit(int nr, volatile void *addr)
34 unsigned long mask = BIT_MASK(nr);
35 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
40 extern int test_and_set_bit(int nr, volatile void * addr);
42 static inline int __test_and_set_bit(int nr, volatile void *addr)
44 unsigned long mask = BIT_MASK(nr);
45 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
46 unsigned long old = *p;
49 return (old & mask) != 0;
52 extern int test_and_clear_bit(int nr, volatile void * addr);
54 static inline int __test_and_clear_bit(int nr, volatile void *addr)
56 unsigned long mask = BIT_MASK(nr);
57 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
58 unsigned long old = *p;
61 return (old & mask) != 0;
64 extern int test_and_change_bit(int nr, volatile void * addr);
66 static inline int __test_and_change_bit(int nr, volatile void *addr)
68 unsigned long mask = BIT_MASK(nr);
69 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
70 unsigned long old = *p;
73 return (old & mask) != 0;
76 extern int find_first_zero_bit(void * addr, unsigned size);
77 extern int find_next_zero_bit(void * addr, int size, int offset);
80 * This routine doesn't need to be atomic.
82 static inline int test_bit(int nr, const void * addr)
84 return ((unsigned char *) addr)[nr >> 3] & (1U << (nr & 7));
88 * ffz = Find First Zero in word. Undefined if no zero exists,
89 * so code should check against ~0UL first..
91 static inline unsigned long ffz(unsigned long word)
97 if (word & 0x0000ffff) { k -= 16; word <<= 16; }
98 if (word & 0x00ff0000) { k -= 8; word <<= 8; }
99 if (word & 0x0f000000) { k -= 4; word <<= 4; }
100 if (word & 0x30000000) { k -= 2; word <<= 2; }
101 if (word & 0x40000000) { k -= 1; }
106 * ffs: find first bit set. This is defined the same way as
107 * the libc and compiler builtin ffs routines, therefore
108 * differs in spirit from the above ffz (man ffs).
111 #define ffs(x) generic_ffs(x)
114 * hweightN: returns the hamming weight (i.e. the number
115 * of bits set) of a N-bit word
118 #define hweight32(x) generic_hweight32(x)
119 #define hweight16(x) generic_hweight16(x)
120 #define hweight8(x) generic_hweight8(x)
122 #define ext2_set_bit test_and_set_bit
123 #define ext2_clear_bit test_and_clear_bit
124 #define ext2_test_bit test_bit
125 #define ext2_find_first_zero_bit find_first_zero_bit
126 #define ext2_find_next_zero_bit find_next_zero_bit
128 /* Bitmap functions for the minix filesystem. */
129 #define minix_test_and_set_bit(nr,addr) test_and_set_bit(nr,addr)
130 #define minix_set_bit(nr,addr) set_bit(nr,addr)
131 #define minix_test_and_clear_bit(nr,addr) test_and_clear_bit(nr,addr)
132 #define minix_test_bit(nr,addr) test_bit(nr,addr)
133 #define minix_find_first_zero_bit(addr,size) find_first_zero_bit(addr,size)
135 #endif /* __KERNEL__ */
137 #endif /* _ARM_BITOPS_H */