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