include/linux/bitops.h

   1 #ifndef _LINUX_BITOPS_H
   2 #define _LINUX_BITOPS_H
   3 #include <asm/types.h>
   4
   5 #ifdef  __KERNEL__
   6 #define BIT(nr)                 (1UL << (nr))
   7 #define BIT_MASK(nr)            (1UL << ((nr) % BITS_PER_LONG))
   8 #define BIT_WORD(nr)            ((nr) / BITS_PER_LONG)
   9 #define BITS_PER_BYTE           8
  10 #define BITS_TO_LONGS(nr)       DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long))
  11 #endif
  12
  13 /*
  14  * Include this here because some architectures need generic_ffs/fls in
  15  * scope
  16  */
  17 #include <asm/bitops.h>
  18
  19 #define for_each_bit(bit, addr, size) \
  20         for ((bit) = find_first_bit((addr), (size)); \
  21              (bit) < (size); \
  22              (bit) = find_next_bit((addr), (size), (bit) + 1))
  23
  24
  25 static __inline__ int get_bitmask_order(unsigned int count)
  26 {
  27         int order;
  28
  29         order = fls(count);
  30         return order;   /* We could be slightly more clever with -1 here... */
  31 }
  32
  33 static __inline__ int get_count_order(unsigned int count)
  34 {
  35         int order;
  36
  37         order = fls(count) - 1;
  38         if (count & (count - 1))
  39                 order++;
  40         return order;
  41 }
  42
  43 static inline unsigned long hweight_long(unsigned long w)
  44 {
  45         return sizeof(w) == 4 ? hweight32(w) : hweight64(w);
  46 }
  47
  48 /**
  49  * rol32 - rotate a 32-bit value left
  50  * @word: value to rotate
  51  * @shift: bits to roll
  52  */
  53 static inline __u32 rol32(__u32 word, unsigned int shift)
  54 {
  55         return (word << shift) | (word >> (32 - shift));
  56 }
  57
  58 /**
  59  * ror32 - rotate a 32-bit value right
  60  * @word: value to rotate
  61  * @shift: bits to roll
  62  */
  63 static inline __u32 ror32(__u32 word, unsigned int shift)
  64 {
  65         return (word >> shift) | (word << (32 - shift));
  66 }
  67
  68 /**
  69  * rol16 - rotate a 16-bit value left
  70  * @word: value to rotate
  71  * @shift: bits to roll
  72  */
  73 static inline __u16 rol16(__u16 word, unsigned int shift)
  74 {
  75         return (word << shift) | (word >> (16 - shift));
  76 }
  77
  78 /**
  79  * ror16 - rotate a 16-bit value right
  80  * @word: value to rotate
  81  * @shift: bits to roll
  82  */
  83 static inline __u16 ror16(__u16 word, unsigned int shift)
  84 {
  85         return (word >> shift) | (word << (16 - shift));
  86 }
  87
  88 /**
  89  * rol8 - rotate an 8-bit value left
  90  * @word: value to rotate
  91  * @shift: bits to roll
  92  */
  93 static inline __u8 rol8(__u8 word, unsigned int shift)
  94 {
  95         return (word << shift) | (word >> (8 - shift));
  96 }
  97
  98 /**
  99  * ror8 - rotate an 8-bit value right
 100  * @word: value to rotate
 101  * @shift: bits to roll
 102  */
 103 static inline __u8 ror8(__u8 word, unsigned int shift)
 104 {
 105         return (word >> shift) | (word << (8 - shift));
 106 }
 107
 108 static inline unsigned fls_long(unsigned long l)
 109 {
 110         if (sizeof(l) == 4)
 111                 return fls(l);
 112         return fls64(l);
 113 }
 114
 115 #ifdef __KERNEL__
 116 #ifdef CONFIG_GENERIC_FIND_FIRST_BIT
 117
 118 /**
 119  * find_first_bit - find the first set bit in a memory region
 120  * @addr: The address to start the search at
 121  * @size: The maximum size to search
 122  *
 123  * Returns the bit number of the first set bit.
 124  */
 125 extern unsigned long find_first_bit(const unsigned long *addr,
 126                                     unsigned long size);
 127
 128 /**
 129  * find_first_zero_bit - find the first cleared bit in a memory region
 130  * @addr: The address to start the search at
 131  * @size: The maximum size to search
 132  *
 133  * Returns the bit number of the first cleared bit.
 134  */
 135 extern unsigned long find_first_zero_bit(const unsigned long *addr,
 136                                          unsigned long size);
 137
 138 #endif /* CONFIG_GENERIC_FIND_FIRST_BIT */
 139
 140 #ifdef CONFIG_GENERIC_FIND_NEXT_BIT
 141
 142 /**
 143  * find_next_bit - find the next set bit in a memory region
 144  * @addr: The address to base the search on
 145  * @offset: The bitnumber to start searching at
 146  * @size: The bitmap size in bits
 147  */
 148 extern unsigned long find_next_bit(const unsigned long *addr,
 149                                    unsigned long size, unsigned long offset);
 150
 151 /**
 152  * find_next_zero_bit - find the next cleared bit in a memory region
 153  * @addr: The address to base the search on
 154  * @offset: The bitnumber to start searching at
 155  * @size: The bitmap size in bits
 156  */
 157
 158 extern unsigned long find_next_zero_bit(const unsigned long *addr,
 159                                         unsigned long size,
 160                                         unsigned long offset);
 161
 162 #endif /* CONFIG_GENERIC_FIND_NEXT_BIT */
 163 #endif /* __KERNEL__ */
 164 #endif