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_set_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 static __inline__ int get_bitmask_order(unsigned int count)
  25 {
  26         int order;
  27
  28         order = fls(count);
  29         return order;   /* We could be slightly more clever with -1 here... */
  30 }
  31
  32 static __inline__ int get_count_order(unsigned int count)
  33 {
  34         int order;
  35
  36         order = fls(count) - 1;
  37         if (count & (count - 1))
  38                 order++;
  39         return order;
  40 }
  41
  42 static inline unsigned long hweight_long(unsigned long w)
  43 {
  44         return sizeof(w) == 4 ? hweight32(w) : hweight64(w);
  45 }
  46
  47 /*
  48  * Clearly slow versions of the hweightN() functions, their benefit is
  49  * of course compile time evaluation of constant arguments.
  50  */
  51 #define HWEIGHT8(w)                                     \
  52       ( BUILD_BUG_ON_ZERO(!__builtin_constant_p(w)) +   \
  53         (!!((w) & (1ULL << 0))) +                       \
  54         (!!((w) & (1ULL << 1))) +                       \
  55         (!!((w) & (1ULL << 2))) +                       \
  56         (!!((w) & (1ULL << 3))) +                       \
  57         (!!((w) & (1ULL << 4))) +                       \
  58         (!!((w) & (1ULL << 5))) +                       \
  59         (!!((w) & (1ULL << 6))) +                       \
  60         (!!((w) & (1ULL << 7))) )
  61
  62 #define HWEIGHT16(w) (HWEIGHT8(w)  + HWEIGHT8((w) >> 8))
  63 #define HWEIGHT32(w) (HWEIGHT16(w) + HWEIGHT16((w) >> 16))
  64 #define HWEIGHT64(w) (HWEIGHT32(w) + HWEIGHT32((w) >> 32))
  65
  66 /*
  67  * Type invariant version that simply casts things to the
  68  * largest type.
  69  */
  70 #define HWEIGHT(w)   HWEIGHT64((u64)(w))
  71
  72 /**
  73  * rol32 - rotate a 32-bit value left
  74  * @word: value to rotate
  75  * @shift: bits to roll
  76  */
  77 static inline __u32 rol32(__u32 word, unsigned int shift)
  78 {
  79         return (word << shift) | (word >> (32 - shift));
  80 }
  81
  82 /**
  83  * ror32 - rotate a 32-bit value right
  84  * @word: value to rotate
  85  * @shift: bits to roll
  86  */
  87 static inline __u32 ror32(__u32 word, unsigned int shift)
  88 {
  89         return (word >> shift) | (word << (32 - shift));
  90 }
  91
  92 /**
  93  * rol16 - rotate a 16-bit value left
  94  * @word: value to rotate
  95  * @shift: bits to roll
  96  */
  97 static inline __u16 rol16(__u16 word, unsigned int shift)
  98 {
  99         return (word << shift) | (word >> (16 - shift));
 100 }
 101
 102 /**
 103  * ror16 - rotate a 16-bit value right
 104  * @word: value to rotate
 105  * @shift: bits to roll
 106  */
 107 static inline __u16 ror16(__u16 word, unsigned int shift)
 108 {
 109         return (word >> shift) | (word << (16 - shift));
 110 }
 111
 112 /**
 113  * rol8 - rotate an 8-bit value left
 114  * @word: value to rotate
 115  * @shift: bits to roll
 116  */
 117 static inline __u8 rol8(__u8 word, unsigned int shift)
 118 {
 119         return (word << shift) | (word >> (8 - shift));
 120 }
 121
 122 /**
 123  * ror8 - rotate an 8-bit value right
 124  * @word: value to rotate
 125  * @shift: bits to roll
 126  */
 127 static inline __u8 ror8(__u8 word, unsigned int shift)
 128 {
 129         return (word >> shift) | (word << (8 - shift));
 130 }
 131
 132 static inline unsigned fls_long(unsigned long l)
 133 {
 134         if (sizeof(l) == 4)
 135                 return fls(l);
 136         return fls64(l);
 137 }
 138
 139 /**
 140  * __ffs64 - find first set bit in a 64 bit word
 141  * @word: The 64 bit word
 142  *
 143  * On 64 bit arches this is a synomyn for __ffs
 144  * The result is not defined if no bits are set, so check that @word
 145  * is non-zero before calling this.
 146  */
 147 static inline unsigned long __ffs64(u64 word)
 148 {
 149 #if BITS_PER_LONG == 32
 150         if (((u32)word) == 0UL)
 151                 return __ffs((u32)(word >> 32)) + 32;
 152 #elif BITS_PER_LONG != 64
 153 #error BITS_PER_LONG not 32 or 64
 154 #endif
 155         return __ffs((unsigned long)word);
 156 }
 157
 158 #ifdef __KERNEL__
 159 #ifdef CONFIG_GENERIC_FIND_FIRST_BIT
 160
 161 /**
 162  * find_first_bit - find the first set bit in a memory region
 163  * @addr: The address to start the search at
 164  * @size: The maximum size to search
 165  *
 166  * Returns the bit number of the first set bit.
 167  */
 168 extern unsigned long find_first_bit(const unsigned long *addr,
 169                                     unsigned long size);
 170
 171 /**
 172  * find_first_zero_bit - find the first cleared bit in a memory region
 173  * @addr: The address to start the search at
 174  * @size: The maximum size to search
 175  *
 176  * Returns the bit number of the first cleared bit.
 177  */
 178 extern unsigned long find_first_zero_bit(const unsigned long *addr,
 179                                          unsigned long size);
 180 #endif /* CONFIG_GENERIC_FIND_FIRST_BIT */
 181
 182 #ifdef CONFIG_GENERIC_FIND_LAST_BIT
 183 /**
 184  * find_last_bit - find the last set bit in a memory region
 185  * @addr: The address to start the search at
 186  * @size: The maximum size to search
 187  *
 188  * Returns the bit number of the first set bit, or size.
 189  */
 190 extern unsigned long find_last_bit(const unsigned long *addr,
 191                                    unsigned long size);
 192 #endif /* CONFIG_GENERIC_FIND_LAST_BIT */
 193
 194 #ifdef CONFIG_GENERIC_FIND_NEXT_BIT
 195
 196 /**
 197  * find_next_bit - find the next set bit in a memory region
 198  * @addr: The address to base the search on
 199  * @offset: The bitnumber to start searching at
 200  * @size: The bitmap size in bits
 201  */
 202 extern unsigned long find_next_bit(const unsigned long *addr,
 203                                    unsigned long size, unsigned long offset);
 204
 205 /**
 206  * find_next_zero_bit - find the next cleared bit in a memory region
 207  * @addr: The address to base the search on
 208  * @offset: The bitnumber to start searching at
 209  * @size: The bitmap size in bits
 210  */
 211
 212 extern unsigned long find_next_zero_bit(const unsigned long *addr,
 213                                         unsigned long size,
 214                                         unsigned long offset);
 215
 216 #endif /* CONFIG_GENERIC_FIND_NEXT_BIT */
 217 #endif /* __KERNEL__ */
 218 #endif