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