include/linux/bitops.h

   1 #ifndef _LINUX_BITOPS_H
   2 #define _LINUX_BITOPS_H
   3
   4 #include <asm/types.h>
   5 #include <linux/compiler.h>
   6
   7 #define BIT(nr)                 (1UL << (nr))
   8 #define BIT_MASK(nr)            (1UL << ((nr) % BITS_PER_LONG))
   9 #define BIT_WORD(nr)            ((nr) / BITS_PER_LONG)
  10
  11 /*
  12  * Create a contiguous bitmask starting at bit position @l and ending at
  13  * position @h. For example
  14  * GENMASK_ULL(39, 21) gives us the 64bit vector 0x000000ffffe00000.
  15  */
  16 #define GENMASK(h, l) \
  17         (((~0UL) << (l)) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
  18
  19 #define GENMASK_ULL(h, l) \
  20         (((~0ULL) << (l)) & (~0ULL >> (BITS_PER_LONG_LONG - 1 - (h))))
  21
  22 /*
  23  * ffs: find first bit set. This is defined the same way as
  24  * the libc and compiler builtin ffs routines, therefore
  25  * differs in spirit from the above ffz (man ffs).
  26  */
  27
  28 static inline int generic_ffs(int x)
  29 {
  30         int r = 1;
  31
  32         if (!x)
  33                 return 0;
  34         if (!(x & 0xffff)) {
  35                 x >>= 16;
  36                 r += 16;
  37         }
  38         if (!(x & 0xff)) {
  39                 x >>= 8;
  40                 r += 8;
  41         }
  42         if (!(x & 0xf)) {
  43                 x >>= 4;
  44                 r += 4;
  45         }
  46         if (!(x & 3)) {
  47                 x >>= 2;
  48                 r += 2;
  49         }
  50         if (!(x & 1)) {
  51                 x >>= 1;
  52                 r += 1;
  53         }
  54         return r;
  55 }
  56
  57 /**
  58  * fls - find last (most-significant) bit set
  59  * @x: the word to search
  60  *
  61  * This is defined the same way as ffs.
  62  * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
  63  */
  64 static inline int generic_fls(int x)
  65 {
  66         int r = 32;
  67
  68         if (!x)
  69                 return 0;
  70         if (!(x & 0xffff0000u)) {
  71                 x <<= 16;
  72                 r -= 16;
  73         }
  74         if (!(x & 0xff000000u)) {
  75                 x <<= 8;
  76                 r -= 8;
  77         }
  78         if (!(x & 0xf0000000u)) {
  79                 x <<= 4;
  80                 r -= 4;
  81         }
  82         if (!(x & 0xc0000000u)) {
  83                 x <<= 2;
  84                 r -= 2;
  85         }
  86         if (!(x & 0x80000000u)) {
  87                 x <<= 1;
  88                 r -= 1;
  89         }
  90         return r;
  91 }
  92
  93
  94 /*
  95  * hweightN: returns the hamming weight (i.e. the number
  96  * of bits set) of a N-bit word
  97  */
  98
  99 static inline unsigned int generic_hweight32(unsigned int w)
 100 {
 101         unsigned int res = (w & 0x55555555) + ((w >> 1) & 0x55555555);
 102         res = (res & 0x33333333) + ((res >> 2) & 0x33333333);
 103         res = (res & 0x0F0F0F0F) + ((res >> 4) & 0x0F0F0F0F);
 104         res = (res & 0x00FF00FF) + ((res >> 8) & 0x00FF00FF);
 105         return (res & 0x0000FFFF) + ((res >> 16) & 0x0000FFFF);
 106 }
 107
 108 static inline unsigned int generic_hweight16(unsigned int w)
 109 {
 110         unsigned int res = (w & 0x5555) + ((w >> 1) & 0x5555);
 111         res = (res & 0x3333) + ((res >> 2) & 0x3333);
 112         res = (res & 0x0F0F) + ((res >> 4) & 0x0F0F);
 113         return (res & 0x00FF) + ((res >> 8) & 0x00FF);
 114 }
 115
 116 static inline unsigned int generic_hweight8(unsigned int w)
 117 {
 118         unsigned int res = (w & 0x55) + ((w >> 1) & 0x55);
 119         res = (res & 0x33) + ((res >> 2) & 0x33);
 120         return (res & 0x0F) + ((res >> 4) & 0x0F);
 121 }
 122
 123 #include <asm/bitops.h>
 124
 125 /* linux/include/asm-generic/bitops/non-atomic.h */
 126
 127 #ifndef PLATFORM__SET_BIT
 128 # define __set_bit generic_set_bit
 129 #endif
 130
 131 #ifndef PLATFORM__CLEAR_BIT
 132 # define __clear_bit generic_clear_bit
 133 #endif
 134
 135 #ifndef PLATFORM_FFS
 136 # define ffs generic_ffs
 137 #endif
 138
 139 #ifndef PLATFORM_FLS
 140 # define fls generic_fls
 141 #endif
 142
 143 static inline unsigned fls_long(unsigned long l)
 144 {
 145         if (sizeof(l) == 4)
 146                 return fls(l);
 147         return fls64(l);
 148 }
 149
 150 /**
 151  * __ffs64 - find first set bit in a 64 bit word
 152  * @word: The 64 bit word
 153  *
 154  * On 64 bit arches this is a synomyn for __ffs
 155  * The result is not defined if no bits are set, so check that @word
 156  * is non-zero before calling this.
 157  */
 158 static inline unsigned long __ffs64(u64 word)
 159 {
 160 #if BITS_PER_LONG == 32
 161         if (((u32)word) == 0UL)
 162                 return __ffs((u32)(word >> 32)) + 32;
 163 #elif BITS_PER_LONG != 64
 164 #error BITS_PER_LONG not 32 or 64
 165 #endif
 166         return __ffs((unsigned long)word);
 167 }
 168
 169 /**
 170  * __set_bit - Set a bit in memory
 171  * @nr: the bit to set
 172  * @addr: the address to start counting from
 173  *
 174  * Unlike set_bit(), this function is non-atomic and may be reordered.
 175  * If it's called on the same region of memory simultaneously, the effect
 176  * may be that only one operation succeeds.
 177  */
 178 static inline void generic_set_bit(int nr, volatile unsigned long *addr)
 179 {
 180         unsigned long mask = BIT_MASK(nr);
 181         unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
 182
 183         *p  |= mask;
 184 }
 185
 186 static inline void generic_clear_bit(int nr, volatile unsigned long *addr)
 187 {
 188         unsigned long mask = BIT_MASK(nr);
 189         unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
 190
 191         *p &= ~mask;
 192 }
 193
 194 #endif