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 #include <asm/proc/system.h>
22 #define smp_mb__before_clear_bit() do { } while (0)
23 #define smp_mb__after_clear_bit() do { } while (0)
26 * Function prototypes to keep gcc -Wall happy.
28 static inline void set_bit(int nr, volatile unsigned long * addr)
30 unsigned long mask = BIT_MASK(nr);
31 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
36 static inline void clear_bit(int nr, volatile unsigned long * addr)
38 unsigned long mask = BIT_MASK(nr);
39 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
44 extern void change_bit(int nr, volatile void * addr);
46 static inline void __change_bit(int nr, volatile void *addr)
48 unsigned long mask = BIT_MASK(nr);
49 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
54 static inline int __test_and_set_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 static inline int test_and_set_bit(int nr, volatile void * addr)
69 local_irq_save(flags);
70 out = __test_and_set_bit(nr, addr);
71 local_irq_restore(flags);
76 static inline int __test_and_clear_bit(int nr, volatile void *addr)
78 unsigned long mask = BIT_MASK(nr);
79 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
80 unsigned long old = *p;
83 return (old & mask) != 0;
86 static inline int test_and_clear_bit(int nr, volatile void * addr)
91 local_irq_save(flags);
92 out = __test_and_clear_bit(nr, addr);
93 local_irq_restore(flags);
98 extern int test_and_change_bit(int nr, volatile void * addr);
100 static inline int __test_and_change_bit(int nr, volatile void *addr)
102 unsigned long mask = BIT_MASK(nr);
103 unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
104 unsigned long old = *p;
107 return (old & mask) != 0;
110 extern int find_first_zero_bit(void * addr, unsigned size);
111 extern int find_next_zero_bit(void * addr, int size, int offset);
114 * This routine doesn't need to be atomic.
116 static inline int test_bit(int nr, const void * addr)
118 return ((unsigned char *) addr)[nr >> 3] & (1U << (nr & 7));
122 * ffz = Find First Zero in word. Undefined if no zero exists,
123 * so code should check against ~0UL first..
125 static inline unsigned long ffz(unsigned long word)
131 if (word & 0x0000ffff) { k -= 16; word <<= 16; }
132 if (word & 0x00ff0000) { k -= 8; word <<= 8; }
133 if (word & 0x0f000000) { k -= 4; word <<= 4; }
134 if (word & 0x30000000) { k -= 2; word <<= 2; }
135 if (word & 0x40000000) { k -= 1; }
140 * hweightN: returns the hamming weight (i.e. the number
141 * of bits set) of a N-bit word
144 #define hweight32(x) generic_hweight32(x)
145 #define hweight16(x) generic_hweight16(x)
146 #define hweight8(x) generic_hweight8(x)
148 #define ext2_set_bit test_and_set_bit
149 #define ext2_clear_bit test_and_clear_bit
150 #define ext2_test_bit test_bit
151 #define ext2_find_first_zero_bit find_first_zero_bit
152 #define ext2_find_next_zero_bit find_next_zero_bit
154 /* Bitmap functions for the minix filesystem. */
155 #define minix_test_and_set_bit(nr,addr) test_and_set_bit(nr,addr)
156 #define minix_set_bit(nr,addr) set_bit(nr,addr)
157 #define minix_test_and_clear_bit(nr,addr) test_and_clear_bit(nr,addr)
158 #define minix_test_bit(nr,addr) test_bit(nr,addr)
159 #define minix_find_first_zero_bit(addr,size) find_first_zero_bit(addr,size)
161 #endif /* __KERNEL__ */
163 #endif /* _ARM_BITOPS_H */