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
  13extern unsigned int __sw_hweight8(unsigned int w);
  14extern unsigned int __sw_hweight16(unsigned int w);
  15extern unsigned int __sw_hweight32(unsigned int w);
  16extern 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
  46static __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
  54static __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
  64static 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 */
  74static 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 */
  84static 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 */
  94static 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 */
 104static 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 */
 114static 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 */
 124static 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 */
 134static 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 */
 144static 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 */
 154static inline __s32 sign_extend32(__u32 value, int index)
 155{
 156        __u8 shift = 31 - index;
 157        return (__s32)(value << shift) >> shift;
 158}
 159
 160static 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 */
 175static 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 */
 196extern unsigned long find_last_bit(const unsigned long *addr,
 197                                   unsigned long size);
 198#endif
 199
 200#endif /* __KERNEL__ */
 201#endif
 202
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