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 static __inline__ int get_bitmask_order(unsigned int count)
  30 {
  31         int order;
  32
  33         order = fls(count);
  34         return order;   /* We could be slightly more clever with -1 here... */
  35 }
  36
  37 static __inline__ int get_count_order(unsigned int count)
  38 {
  39         int order;
  40
  41         order = fls(count) - 1;
  42         if (count & (count - 1))
  43                 order++;
  44         return order;
  45 }
  46
  47 static inline unsigned long hweight_long(unsigned long w)
  48 {
  49         return sizeof(w) == 4 ? hweight32(w) : hweight64(w);
  50 }
  51
  52 /**
  53  * rol32 - rotate a 32-bit value left
  54  * @word: value to rotate
  55  * @shift: bits to roll
  56  */
  57 static inline __u32 rol32(__u32 word, unsigned int shift)
  58 {
  59         return (word << shift) | (word >> (32 - shift));
  60 }
  61
  62 /**
  63  * ror32 - rotate a 32-bit value right
  64  * @word: value to rotate
  65  * @shift: bits to roll
  66  */
  67 static inline __u32 ror32(__u32 word, unsigned int shift)
  68 {
  69         return (word >> shift) | (word << (32 - shift));
  70 }
  71
  72 /**
  73  * rol16 - rotate a 16-bit value left
  74  * @word: value to rotate
  75  * @shift: bits to roll
  76  */
  77 static inline __u16 rol16(__u16 word, unsigned int shift)
  78 {
  79         return (word << shift) | (word >> (16 - shift));
  80 }
  81
  82 /**
  83  * ror16 - rotate a 16-bit value right
  84  * @word: value to rotate
  85  * @shift: bits to roll
  86  */
  87 static inline __u16 ror16(__u16 word, unsigned int shift)
  88 {
  89         return (word >> shift) | (word << (16 - shift));
  90 }
  91
  92 /**
  93  * rol8 - rotate an 8-bit value left
  94  * @word: value to rotate
  95  * @shift: bits to roll
  96  */
  97 static inline __u8 rol8(__u8 word, unsigned int shift)
  98 {
  99         return (word << shift) | (word >> (8 - shift));
 100 }
 101
 102 /**
 103  * ror8 - rotate an 8-bit value right
 104  * @word: value to rotate
 105  * @shift: bits to roll
 106  */
 107 static inline __u8 ror8(__u8 word, unsigned int shift)
 108 {
 109         return (word >> shift) | (word << (8 - shift));
 110 }
 111
 112 static inline unsigned fls_long(unsigned long l)
 113 {
 114         if (sizeof(l) == 4)
 115                 return fls(l);
 116         return fls64(l);
 117 }
 118
 119 /**
 120  * __ffs64 - find first set bit in a 64 bit word
 121  * @word: The 64 bit word
 122  *
 123  * On 64 bit arches this is a synomyn for __ffs
 124  * The result is not defined if no bits are set, so check that @word
 125  * is non-zero before calling this.
 126  */
 127 static inline unsigned long __ffs64(u64 word)
 128 {
 129 #if BITS_PER_LONG == 32
 130         if (((u32)word) == 0UL)
 131                 return __ffs((u32)(word >> 32)) + 32;
 132 #elif BITS_PER_LONG != 64
 133 #error BITS_PER_LONG not 32 or 64
 134 #endif
 135         return __ffs((unsigned long)word);
 136 }
 137
 138 #ifdef __KERNEL__
 139
 140 #ifdef CONFIG_GENERIC_FIND_LAST_BIT
 141 /**
 142  * find_last_bit - find the last set bit in a memory region
 143  * @addr: The address to start the search at
 144  * @size: The maximum size to search
 145  *
 146  * Returns the bit number of the first set bit, or size.
 147  */
 148 extern unsigned long find_last_bit(const unsigned long *addr,
 149                                    unsigned long size);
 150 #endif /* CONFIG_GENERIC_FIND_LAST_BIT */
 151
 152 #endif /* __KERNEL__ */
 153 #endif