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  * Clearly slow versions of the hweightN() functions, their benefit is
  50  * of course compile time evaluation of constant arguments.
  51  */
  52 #define HWEIGHT8(w)                                     \
  53       ( BUILD_BUG_ON_ZERO(!__builtin_constant_p(w)) +   \
  54         (!!((w) & (1ULL << 0))) +                       \
  55         (!!((w) & (1ULL << 1))) +                       \
  56         (!!((w) & (1ULL << 2))) +                       \
  57         (!!((w) & (1ULL << 3))) +                       \
  58         (!!((w) & (1ULL << 4))) +                       \
  59         (!!((w) & (1ULL << 5))) +                       \
  60         (!!((w) & (1ULL << 6))) +                       \
  61         (!!((w) & (1ULL << 7))) )
  62
  63 #define HWEIGHT16(w) (HWEIGHT8(w)  + HWEIGHT8((w) >> 8))
  64 #define HWEIGHT32(w) (HWEIGHT16(w) + HWEIGHT16((w) >> 16))
  65 #define HWEIGHT64(w) (HWEIGHT32(w) + HWEIGHT32((w) >> 32))
  66
  67 /*
  68  * Type invariant version that simply casts things to the
  69  * largest type.
  70  */
  71 #define HWEIGHT(w)   HWEIGHT64((u64)(w))
  72
  73 /**
  74  * rol32 - rotate a 32-bit value left
  75  * @word: value to rotate
  76  * @shift: bits to roll
  77  */
  78 static inline __u32 rol32(__u32 word, unsigned int shift)
  79 {
  80         return (word << shift) | (word >> (32 - shift));
  81 }
  82
  83 /**
  84  * ror32 - rotate a 32-bit value right
  85  * @word: value to rotate
  86  * @shift: bits to roll
  87  */
  88 static inline __u32 ror32(__u32 word, unsigned int shift)
  89 {
  90         return (word >> shift) | (word << (32 - shift));
  91 }
  92
  93 /**
  94  * rol16 - rotate a 16-bit value left
  95  * @word: value to rotate
  96  * @shift: bits to roll
  97  */
  98 static inline __u16 rol16(__u16 word, unsigned int shift)
  99 {
 100         return (word << shift) | (word >> (16 - shift));
 101 }
 102
 103 /**
 104  * ror16 - rotate a 16-bit value right
 105  * @word: value to rotate
 106  * @shift: bits to roll
 107  */
 108 static inline __u16 ror16(__u16 word, unsigned int shift)
 109 {
 110         return (word >> shift) | (word << (16 - shift));
 111 }
 112
 113 /**
 114  * rol8 - rotate an 8-bit value left
 115  * @word: value to rotate
 116  * @shift: bits to roll
 117  */
 118 static inline __u8 rol8(__u8 word, unsigned int shift)
 119 {
 120         return (word << shift) | (word >> (8 - shift));
 121 }
 122
 123 /**
 124  * ror8 - rotate an 8-bit value right
 125  * @word: value to rotate
 126  * @shift: bits to roll
 127  */
 128 static inline __u8 ror8(__u8 word, unsigned int shift)
 129 {
 130         return (word >> shift) | (word << (8 - shift));
 131 }
 132
 133 static inline unsigned fls_long(unsigned long l)
 134 {
 135         if (sizeof(l) == 4)
 136                 return fls(l);
 137         return fls64(l);
 138 }
 139
 140 /**
 141  * __ffs64 - find first set bit in a 64 bit word
 142  * @word: The 64 bit word
 143  *
 144  * On 64 bit arches this is a synomyn for __ffs
 145  * The result is not defined if no bits are set, so check that @word
 146  * is non-zero before calling this.
 147  */
 148 static inline unsigned long __ffs64(u64 word)
 149 {
 150 #if BITS_PER_LONG == 32
 151         if (((u32)word) == 0UL)
 152                 return __ffs((u32)(word >> 32)) + 32;
 153 #elif BITS_PER_LONG != 64
 154 #error BITS_PER_LONG not 32 or 64
 155 #endif
 156         return __ffs((unsigned long)word);
 157 }
 158
 159 #ifdef __KERNEL__
 160 #ifdef CONFIG_GENERIC_FIND_FIRST_BIT
 161
 162 /**
 163  * find_first_bit - find the first set bit in a memory region
 164  * @addr: The address to start the search at
 165  * @size: The maximum size to search
 166  *
 167  * Returns the bit number of the first set bit.
 168  */
 169 extern unsigned long find_first_bit(const unsigned long *addr,
 170                                     unsigned long size);
 171
 172 /**
 173  * find_first_zero_bit - find the first cleared bit in a memory region
 174  * @addr: The address to start the search at
 175  * @size: The maximum size to search
 176  *
 177  * Returns the bit number of the first cleared bit.
 178  */
 179 extern unsigned long find_first_zero_bit(const unsigned long *addr,
 180                                          unsigned long size);
 181 #endif /* CONFIG_GENERIC_FIND_FIRST_BIT */
 182
 183 #ifdef CONFIG_GENERIC_FIND_LAST_BIT
 184 /**
 185  * find_last_bit - find the last set bit in a memory region
 186  * @addr: The address to start the search at
 187  * @size: The maximum size to search
 188  *
 189  * Returns the bit number of the first set bit, or size.
 190  */
 191 extern unsigned long find_last_bit(const unsigned long *addr,
 192                                    unsigned long size);
 193 #endif /* CONFIG_GENERIC_FIND_LAST_BIT */
 194
 195 #ifdef CONFIG_GENERIC_FIND_NEXT_BIT
 196
 197 /**
 198  * find_next_bit - find the next set bit in a memory region
 199  * @addr: The address to base the search on
 200  * @offset: The bitnumber to start searching at
 201  * @size: The bitmap size in bits
 202  */
 203 extern unsigned long find_next_bit(const unsigned long *addr,
 204                                    unsigned long size, unsigned long offset);
 205
 206 /**
 207  * find_next_zero_bit - find the next cleared bit in a memory region
 208  * @addr: The address to base the search on
 209  * @offset: The bitnumber to start searching at
 210  * @size: The bitmap size in bits
 211  */
 212
 213 extern unsigned long find_next_zero_bit(const unsigned long *addr,
 214                                         unsigned long size,
 215                                         unsigned long offset);
 216
 217 #endif /* CONFIG_GENERIC_FIND_NEXT_BIT */
 218 #endif /* __KERNEL__ */
 219 #endif