linux/include/linux/bitops.h
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   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
  24static __inline__ int get_bitmask_order(unsigned int count)
  25{
  26        int order;
  27
  28        order = fls(count);
  29        return order;   /* We could be slightly more clever with -1 here... */
  30}
  31
  32static __inline__ int get_count_order(unsigned int count)
  33{
  34        int order;
  35
  36        order = fls(count) - 1;
  37        if (count & (count - 1))
  38                order++;
  39        return order;
  40}
  41
  42static inline unsigned long hweight_long(unsigned long w)
  43{
  44        return sizeof(w) == 4 ? hweight32(w) : hweight64(w);
  45}
  46
  47/*
  48 * Clearly slow versions of the hweightN() functions, their benefit is
  49 * of course compile time evaluation of constant arguments.
  50 */
  51#define HWEIGHT8(w)                                     \
  52      ( BUILD_BUG_ON_ZERO(!__builtin_constant_p(w)) +   \
  53        (!!((w) & (1ULL << 0))) +                       \
  54        (!!((w) & (1ULL << 1))) +                       \
  55        (!!((w) & (1ULL << 2))) +                       \
  56        (!!((w) & (1ULL << 3))) +                       \
  57        (!!((w) & (1ULL << 4))) +                       \
  58        (!!((w) & (1ULL << 5))) +                       \
  59        (!!((w) & (1ULL << 6))) +                       \
  60        (!!((w) & (1ULL << 7))) )
  61
  62#define HWEIGHT16(w) (HWEIGHT8(w)  + HWEIGHT8((w) >> 8))
  63#define HWEIGHT32(w) (HWEIGHT16(w) + HWEIGHT16((w) >> 16))
  64#define HWEIGHT64(w) (HWEIGHT32(w) + HWEIGHT32((w) >> 32))
  65
  66/*
  67 * Type invariant version that simply casts things to the
  68 * largest type.
  69 */
  70#define HWEIGHT(w)   HWEIGHT64((u64)(w))
  71
  72/**
  73 * rol32 - rotate a 32-bit value left
  74 * @word: value to rotate
  75 * @shift: bits to roll
  76 */
  77static inline __u32 rol32(__u32 word, unsigned int shift)
  78{
  79        return (word << shift) | (word >> (32 - shift));
  80}
  81
  82/**
  83 * ror32 - rotate a 32-bit value right
  84 * @word: value to rotate
  85 * @shift: bits to roll
  86 */
  87static inline __u32 ror32(__u32 word, unsigned int shift)
  88{
  89        return (word >> shift) | (word << (32 - shift));
  90}
  91
  92/**
  93 * rol16 - rotate a 16-bit value left
  94 * @word: value to rotate
  95 * @shift: bits to roll
  96 */
  97static inline __u16 rol16(__u16 word, unsigned int shift)
  98{
  99        return (word << shift) | (word >> (16 - shift));
 100}
 101
 102/**
 103 * ror16 - rotate a 16-bit value right
 104 * @word: value to rotate
 105 * @shift: bits to roll
 106 */
 107static inline __u16 ror16(__u16 word, unsigned int shift)
 108{
 109        return (word >> shift) | (word << (16 - shift));
 110}
 111
 112/**
 113 * rol8 - rotate an 8-bit value left
 114 * @word: value to rotate
 115 * @shift: bits to roll
 116 */
 117static inline __u8 rol8(__u8 word, unsigned int shift)
 118{
 119        return (word << shift) | (word >> (8 - shift));
 120}
 121
 122/**
 123 * ror8 - rotate an 8-bit value right
 124 * @word: value to rotate
 125 * @shift: bits to roll
 126 */
 127static inline __u8 ror8(__u8 word, unsigned int shift)
 128{
 129        return (word >> shift) | (word << (8 - shift));
 130}
 131
 132static inline unsigned fls_long(unsigned long l)
 133{
 134        if (sizeof(l) == 4)
 135                return fls(l);
 136        return fls64(l);
 137}
 138
 139/**
 140 * __ffs64 - find first set bit in a 64 bit word
 141 * @word: The 64 bit word
 142 *
 143 * On 64 bit arches this is a synomyn for __ffs
 144 * The result is not defined if no bits are set, so check that @word
 145 * is non-zero before calling this.
 146 */
 147static inline unsigned long __ffs64(u64 word)
 148{
 149#if BITS_PER_LONG == 32
 150        if (((u32)word) == 0UL)
 151                return __ffs((u32)(word >> 32)) + 32;
 152#elif BITS_PER_LONG != 64
 153#error BITS_PER_LONG not 32 or 64
 154#endif
 155        return __ffs((unsigned long)word);
 156}
 157
 158#ifdef __KERNEL__
 159#ifdef CONFIG_GENERIC_FIND_FIRST_BIT
 160
 161/**
 162 * find_first_bit - find the first set bit in a memory region
 163 * @addr: The address to start the search at
 164 * @size: The maximum size to search
 165 *
 166 * Returns the bit number of the first set bit.
 167 */
 168extern unsigned long find_first_bit(const unsigned long *addr,
 169                                    unsigned long size);
 170
 171/**
 172 * find_first_zero_bit - find the first cleared bit in a memory region
 173 * @addr: The address to start the search at
 174 * @size: The maximum size to search
 175 *
 176 * Returns the bit number of the first cleared bit.
 177 */
 178extern unsigned long find_first_zero_bit(const unsigned long *addr,
 179                                         unsigned long size);
 180#endif /* CONFIG_GENERIC_FIND_FIRST_BIT */
 181
 182#ifdef CONFIG_GENERIC_FIND_LAST_BIT
 183/**
 184 * find_last_bit - find the last set bit in a memory region
 185 * @addr: The address to start the search at
 186 * @size: The maximum size to search
 187 *
 188 * Returns the bit number of the first set bit, or size.
 189 */
 190extern unsigned long find_last_bit(const unsigned long *addr,
 191                                   unsigned long size);
 192#endif /* CONFIG_GENERIC_FIND_LAST_BIT */
 193
 194#ifdef CONFIG_GENERIC_FIND_NEXT_BIT
 195
 196/**
 197 * find_next_bit - find the next set bit in a memory region
 198 * @addr: The address to base the search on
 199 * @offset: The bitnumber to start searching at
 200 * @size: The bitmap size in bits
 201 */
 202extern unsigned long find_next_bit(const unsigned long *addr,
 203                                   unsigned long size, unsigned long offset);
 204
 205/**
 206 * find_next_zero_bit - find the next cleared bit in a memory region
 207 * @addr: The address to base the search on
 208 * @offset: The bitnumber to start searching at
 209 * @size: The bitmap size in bits
 210 */
 211
 212extern unsigned long find_next_zero_bit(const unsigned long *addr,
 213                                        unsigned long size,
 214                                        unsigned long offset);
 215
 216#endif /* CONFIG_GENERIC_FIND_NEXT_BIT */
 217#endif /* __KERNEL__ */
 218#endif
 219
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