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