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 extern unsigned int __sw_hweight8(unsigned int w);
  14 extern unsigned int __sw_hweight16(unsigned int w);
  15 extern unsigned int __sw_hweight32(unsigned int w);
  16 extern unsigned long __sw_hweight64(__u64 w);
  17
  18 /*
  19  * Include this here because some architectures need generic_ffs/fls in
  20  * scope
  21  */
  22 #include <asm/bitops.h>
  23
  24 #define for_each_set_bit(bit, addr, size) \
  25         for ((bit) = find_first_bit((addr), (size));            \
  26              (bit) < (size);                                    \
  27              (bit) = find_next_bit((addr), (size), (bit) + 1))
  28
  29 /* same as for_each_set_bit() but use bit as value to start with */
  30 #define for_each_set_bit_from(bit, addr, size) \
  31         for ((bit) = find_next_bit((addr), (size), (bit));      \
  32              (bit) < (size);                                    \
  33              (bit) = find_next_bit((addr), (size), (bit) + 1))
  34
  35 #define for_each_clear_bit(bit, addr, size) \
  36         for ((bit) = find_first_zero_bit((addr), (size));       \
  37              (bit) < (size);                                    \
  38              (bit) = find_next_zero_bit((addr), (size), (bit) + 1))
  39
  40 /* same as for_each_clear_bit() but use bit as value to start with */
  41 #define for_each_clear_bit_from(bit, addr, size) \
  42         for ((bit) = find_next_zero_bit((addr), (size), (bit)); \
  43              (bit) < (size);                                    \
  44              (bit) = find_next_zero_bit((addr), (size), (bit) + 1))
  45
  46 static __inline__ int get_bitmask_order(unsigned int count)
  47 {
  48         int order;
  49
  50         order = fls(count);
  51         return order;   /* We could be slightly more clever with -1 here... */
  52 }
  53
  54 static __inline__ int get_count_order(unsigned int count)
  55 {
  56         int order;
  57
  58         order = fls(count) - 1;
  59         if (count & (count - 1))
  60                 order++;
  61         return order;
  62 }
  63
  64 static inline unsigned long hweight_long(unsigned long w)
  65 {
  66         return sizeof(w) == 4 ? hweight32(w) : hweight64(w);
  67 }
  68
  69 /**
  70  * rol64 - rotate a 64-bit value left
  71  * @word: value to rotate
  72  * @shift: bits to roll
  73  */
  74 static inline __u64 rol64(__u64 word, unsigned int shift)
  75 {
  76         return (word << shift) | (word >> (64 - shift));
  77 }
  78
  79 /**
  80  * ror64 - rotate a 64-bit value right
  81  * @word: value to rotate
  82  * @shift: bits to roll
  83  */
  84 static inline __u64 ror64(__u64 word, unsigned int shift)
  85 {
  86         return (word >> shift) | (word << (64 - shift));
  87 }
  88
  89 /**
  90  * rol32 - rotate a 32-bit value left
  91  * @word: value to rotate
  92  * @shift: bits to roll
  93  */
  94 static inline __u32 rol32(__u32 word, unsigned int shift)
  95 {
  96         return (word << shift) | (word >> (32 - shift));
  97 }
  98
  99 /**
 100  * ror32 - rotate a 32-bit value right
 101  * @word: value to rotate
 102  * @shift: bits to roll
 103  */
 104 static inline __u32 ror32(__u32 word, unsigned int shift)
 105 {
 106         return (word >> shift) | (word << (32 - shift));
 107 }
 108
 109 /**
 110  * rol16 - rotate a 16-bit value left
 111  * @word: value to rotate
 112  * @shift: bits to roll
 113  */
 114 static inline __u16 rol16(__u16 word, unsigned int shift)
 115 {
 116         return (word << shift) | (word >> (16 - shift));
 117 }
 118
 119 /**
 120  * ror16 - rotate a 16-bit value right
 121  * @word: value to rotate
 122  * @shift: bits to roll
 123  */
 124 static inline __u16 ror16(__u16 word, unsigned int shift)
 125 {
 126         return (word >> shift) | (word << (16 - shift));
 127 }
 128
 129 /**
 130  * rol8 - rotate an 8-bit value left
 131  * @word: value to rotate
 132  * @shift: bits to roll
 133  */
 134 static inline __u8 rol8(__u8 word, unsigned int shift)
 135 {
 136         return (word << shift) | (word >> (8 - shift));
 137 }
 138
 139 /**
 140  * ror8 - rotate an 8-bit value right
 141  * @word: value to rotate
 142  * @shift: bits to roll
 143  */
 144 static inline __u8 ror8(__u8 word, unsigned int shift)
 145 {
 146         return (word >> shift) | (word << (8 - shift));
 147 }
 148
 149 /**
 150  * sign_extend32 - sign extend a 32-bit value using specified bit as sign-bit
 151  * @value: value to sign extend
 152  * @index: 0 based bit index (0<=index<32) to sign bit
 153  */
 154 static inline __s32 sign_extend32(__u32 value, int index)
 155 {
 156         __u8 shift = 31 - index;
 157         return (__s32)(value << shift) >> shift;
 158 }
 159
 160 static inline unsigned fls_long(unsigned long l)
 161 {
 162         if (sizeof(l) == 4)
 163                 return fls(l);
 164         return fls64(l);
 165 }
 166
 167 /**
 168  * __ffs64 - find first set bit in a 64 bit word
 169  * @word: The 64 bit word
 170  *
 171  * On 64 bit arches this is a synomyn for __ffs
 172  * The result is not defined if no bits are set, so check that @word
 173  * is non-zero before calling this.
 174  */
 175 static inline unsigned long __ffs64(u64 word)
 176 {
 177 #if BITS_PER_LONG == 32
 178         if (((u32)word) == 0UL)
 179                 return __ffs((u32)(word >> 32)) + 32;
 180 #elif BITS_PER_LONG != 64
 181 #error BITS_PER_LONG not 32 or 64
 182 #endif
 183         return __ffs((unsigned long)word);
 184 }
 185
 186 #ifdef __KERNEL__
 187
 188 #ifndef find_last_bit
 189 /**
 190  * find_last_bit - find the last set bit in a memory region
 191  * @addr: The address to start the search at
 192  * @size: The maximum size to search
 193  *
 194  * Returns the bit number of the first set bit, or size.
 195  */
 196 extern unsigned long find_last_bit(const unsigned long *addr,
 197                                    unsigned long size);
 198 #endif
 199
 200 #endif /* __KERNEL__ */
 201 #endif