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 /**
 113  * sign_extend32 - sign extend a 32-bit value using specified bit as sign-bit
 114  * @value: value to sign extend
 115  * @index: 0 based bit index (0<=index<32) to sign bit
 116  */
 117 static inline __s32 sign_extend32(__u32 value, int index)
 118 {
 119         __u8 shift = 31 - index;
 120         return (__s32)(value << shift) >> shift;
 121 }
 122
 123 static inline unsigned fls_long(unsigned long l)
 124 {
 125         if (sizeof(l) == 4)
 126                 return fls(l);
 127         return fls64(l);
 128 }
 129
 130 /**
 131  * __ffs64 - find first set bit in a 64 bit word
 132  * @word: The 64 bit word
 133  *
 134  * On 64 bit arches this is a synomyn for __ffs
 135  * The result is not defined if no bits are set, so check that @word
 136  * is non-zero before calling this.
 137  */
 138 static inline unsigned long __ffs64(u64 word)
 139 {
 140 #if BITS_PER_LONG == 32
 141         if (((u32)word) == 0UL)
 142                 return __ffs((u32)(word >> 32)) + 32;
 143 #elif BITS_PER_LONG != 64
 144 #error BITS_PER_LONG not 32 or 64
 145 #endif
 146         return __ffs((unsigned long)word);
 147 }
 148
 149 #ifdef __KERNEL__
 150
 151 #ifdef CONFIG_GENERIC_FIND_LAST_BIT
 152 /**
 153  * find_last_bit - find the last set bit in a memory region
 154  * @addr: The address to start the search at
 155  * @size: The maximum size to search
 156  *
 157  * Returns the bit number of the first set bit, or size.
 158  */
 159 extern unsigned long find_last_bit(const unsigned long *addr,
 160                                    unsigned long size);
 161 #endif /* CONFIG_GENERIC_FIND_LAST_BIT */
 162
 163 #endif /* __KERNEL__ */
 164 #endif