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_ULL(nr)             (1ULL << (nr))
   8 #define BIT_MASK(nr)            (1UL << ((nr) % BITS_PER_LONG))
   9 #define BIT_WORD(nr)            ((nr) / BITS_PER_LONG)
  10 #define BIT_ULL_MASK(nr)        (1ULL << ((nr) % BITS_PER_LONG_LONG))
  11 #define BIT_ULL_WORD(nr)        ((nr) / BITS_PER_LONG_LONG)
  12 #define BITS_PER_BYTE           8
  13 #define BITS_TO_LONGS(nr)       DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long))
  14 #endif
  15
  16 /*
  17  * Create a contiguous bitmask starting at bit position @l and ending at
  18  * position @h. For example
  19  * GENMASK_ULL(39, 21) gives us the 64bit vector 0x000000ffffe00000.
  20  */
  21 #define GENMASK(h, l) \
  22         (((~0UL) << (l)) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
  23
  24 #define GENMASK_ULL(h, l) \
  25         (((~0ULL) << (l)) & (~0ULL >> (BITS_PER_LONG_LONG - 1 - (h))))
  26
  27 extern unsigned int __sw_hweight8(unsigned int w);
  28 extern unsigned int __sw_hweight16(unsigned int w);
  29 extern unsigned int __sw_hweight32(unsigned int w);
  30 extern unsigned long __sw_hweight64(__u64 w);
  31
  32 /*
  33  * Include this here because some architectures need generic_ffs/fls in
  34  * scope
  35  */
  36 #include <asm/bitops.h>
  37
  38 #define for_each_set_bit(bit, addr, size) \
  39         for ((bit) = find_first_bit((addr), (size));            \
  40              (bit) < (size);                                    \
  41              (bit) = find_next_bit((addr), (size), (bit) + 1))
  42
  43 /* same as for_each_set_bit() but use bit as value to start with */
  44 #define for_each_set_bit_from(bit, addr, size) \
  45         for ((bit) = find_next_bit((addr), (size), (bit));      \
  46              (bit) < (size);                                    \
  47              (bit) = find_next_bit((addr), (size), (bit) + 1))
  48
  49 #define for_each_clear_bit(bit, addr, size) \
  50         for ((bit) = find_first_zero_bit((addr), (size));       \
  51              (bit) < (size);                                    \
  52              (bit) = find_next_zero_bit((addr), (size), (bit) + 1))
  53
  54 /* same as for_each_clear_bit() but use bit as value to start with */
  55 #define for_each_clear_bit_from(bit, addr, size) \
  56         for ((bit) = find_next_zero_bit((addr), (size), (bit)); \
  57              (bit) < (size);                                    \
  58              (bit) = find_next_zero_bit((addr), (size), (bit) + 1))
  59
  60 static inline int get_bitmask_order(unsigned int count)
  61 {
  62         int order;
  63
  64         order = fls(count);
  65         return order;   /* We could be slightly more clever with -1 here... */
  66 }
  67
  68 static inline int get_count_order(unsigned int count)
  69 {
  70         int order;
  71
  72         order = fls(count) - 1;
  73         if (count & (count - 1))
  74                 order++;
  75         return order;
  76 }
  77
  78 static __always_inline unsigned long hweight_long(unsigned long w)
  79 {
  80         return sizeof(w) == 4 ? hweight32(w) : hweight64(w);
  81 }
  82
  83 /**
  84  * rol64 - rotate a 64-bit value left
  85  * @word: value to rotate
  86  * @shift: bits to roll
  87  */
  88 static inline __u64 rol64(__u64 word, unsigned int shift)
  89 {
  90         return (word << shift) | (word >> (64 - shift));
  91 }
  92
  93 /**
  94  * ror64 - rotate a 64-bit value right
  95  * @word: value to rotate
  96  * @shift: bits to roll
  97  */
  98 static inline __u64 ror64(__u64 word, unsigned int shift)
  99 {
 100         return (word >> shift) | (word << (64 - shift));
 101 }
 102
 103 /**
 104  * rol32 - rotate a 32-bit value left
 105  * @word: value to rotate
 106  * @shift: bits to roll
 107  */
 108 static inline __u32 rol32(__u32 word, unsigned int shift)
 109 {
 110         return (word << shift) | (word >> ((-shift) & 31));
 111 }
 112
 113 /**
 114  * ror32 - rotate a 32-bit value right
 115  * @word: value to rotate
 116  * @shift: bits to roll
 117  */
 118 static inline __u32 ror32(__u32 word, unsigned int shift)
 119 {
 120         return (word >> shift) | (word << (32 - shift));
 121 }
 122
 123 /**
 124  * rol16 - rotate a 16-bit value left
 125  * @word: value to rotate
 126  * @shift: bits to roll
 127  */
 128 static inline __u16 rol16(__u16 word, unsigned int shift)
 129 {
 130         return (word << shift) | (word >> (16 - shift));
 131 }
 132
 133 /**
 134  * ror16 - rotate a 16-bit value right
 135  * @word: value to rotate
 136  * @shift: bits to roll
 137  */
 138 static inline __u16 ror16(__u16 word, unsigned int shift)
 139 {
 140         return (word >> shift) | (word << (16 - shift));
 141 }
 142
 143 /**
 144  * rol8 - rotate an 8-bit value left
 145  * @word: value to rotate
 146  * @shift: bits to roll
 147  */
 148 static inline __u8 rol8(__u8 word, unsigned int shift)
 149 {
 150         return (word << shift) | (word >> (8 - shift));
 151 }
 152
 153 /**
 154  * ror8 - rotate an 8-bit value right
 155  * @word: value to rotate
 156  * @shift: bits to roll
 157  */
 158 static inline __u8 ror8(__u8 word, unsigned int shift)
 159 {
 160         return (word >> shift) | (word << (8 - shift));
 161 }
 162
 163 /**
 164  * sign_extend32 - sign extend a 32-bit value using specified bit as sign-bit
 165  * @value: value to sign extend
 166  * @index: 0 based bit index (0<=index<32) to sign bit
 167  *
 168  * This is safe to use for 16- and 8-bit types as well.
 169  */
 170 static inline __s32 sign_extend32(__u32 value, int index)
 171 {
 172         __u8 shift = 31 - index;
 173         return (__s32)(value << shift) >> shift;
 174 }
 175
 176 /**
 177  * sign_extend64 - sign extend a 64-bit value using specified bit as sign-bit
 178  * @value: value to sign extend
 179  * @index: 0 based bit index (0<=index<64) to sign bit
 180  */
 181 static inline __s64 sign_extend64(__u64 value, int index)
 182 {
 183         __u8 shift = 63 - index;
 184         return (__s64)(value << shift) >> shift;
 185 }
 186
 187 static inline unsigned fls_long(unsigned long l)
 188 {
 189         if (sizeof(l) == 4)
 190                 return fls(l);
 191         return fls64(l);
 192 }
 193
 194 /**
 195  * __ffs64 - find first set bit in a 64 bit word
 196  * @word: The 64 bit word
 197  *
 198  * On 64 bit arches this is a synomyn for __ffs
 199  * The result is not defined if no bits are set, so check that @word
 200  * is non-zero before calling this.
 201  */
 202 static inline unsigned long __ffs64(u64 word)
 203 {
 204 #if BITS_PER_LONG == 32
 205         if (((u32)word) == 0UL)
 206                 return __ffs((u32)(word >> 32)) + 32;
 207 #elif BITS_PER_LONG != 64
 208 #error BITS_PER_LONG not 32 or 64
 209 #endif
 210         return __ffs((unsigned long)word);
 211 }
 212
 213 #ifdef __KERNEL__
 214
 215 #ifndef set_mask_bits
 216 #define set_mask_bits(ptr, _mask, _bits)        \
 217 ({                                                              \
 218         const typeof(*ptr) mask = (_mask), bits = (_bits);      \
 219         typeof(*ptr) old, new;                                  \
 220                                                                 \
 221         do {                                                    \
 222                 old = ACCESS_ONCE(*ptr);                        \
 223                 new = (old & ~mask) | bits;                     \
 224         } while (cmpxchg(ptr, old, new) != old);                \
 225                                                                 \
 226         new;                                                    \
 227 })
 228 #endif
 229
 230 #ifndef bit_clear_unless
 231 #define bit_clear_unless(ptr, _clear, _test)    \
 232 ({                                                              \
 233         const typeof(*ptr) clear = (_clear), test = (_test);    \
 234         typeof(*ptr) old, new;                                  \
 235                                                                 \
 236         do {                                                    \
 237                 old = ACCESS_ONCE(*ptr);                        \
 238                 new = old & ~clear;                             \
 239         } while (!(old & test) &&                               \
 240                  cmpxchg(ptr, old, new) != old);                \
 241                                                                 \
 242         !(old & test);                                          \
 243 })
 244 #endif
 245
 246 #ifndef find_last_bit
 247 /**
 248  * find_last_bit - find the last set bit in a memory region
 249  * @addr: The address to start the search at
 250  * @size: The number of bits to search
 251  *
 252  * Returns the bit number of the last set bit, or size.
 253  */
 254 extern unsigned long find_last_bit(const unsigned long *addr,
 255                                    unsigned long size);
 256 #endif
 257
 258 #endif /* __KERNEL__ */
 259 #endif