linux/include/linux/bitops.h
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   1/* SPDX-License-Identifier: GPL-2.0 */
   2#ifndef _LINUX_BITOPS_H
   3#define _LINUX_BITOPS_H
   4#include <asm/types.h>
   5
   6#ifdef  __KERNEL__
   7#define BIT(nr)                 (1UL << (nr))
   8#define BIT_ULL(nr)             (1ULL << (nr))
   9#define BIT_MASK(nr)            (1UL << ((nr) % BITS_PER_LONG))
  10#define BIT_WORD(nr)            ((nr) / BITS_PER_LONG)
  11#define BIT_ULL_MASK(nr)        (1ULL << ((nr) % BITS_PER_LONG_LONG))
  12#define BIT_ULL_WORD(nr)        ((nr) / BITS_PER_LONG_LONG)
  13#define BITS_PER_BYTE           8
  14#define BITS_TO_LONGS(nr)       DIV_ROUND_UP(nr, BITS_PER_BYTE * sizeof(long))
  15#endif
  16
  17/*
  18 * Create a contiguous bitmask starting at bit position @l and ending at
  19 * position @h. For example
  20 * GENMASK_ULL(39, 21) gives us the 64bit vector 0x000000ffffe00000.
  21 */
  22#define GENMASK(h, l) \
  23        (((~0UL) - (1UL << (l)) + 1) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
  24
  25#define GENMASK_ULL(h, l) \
  26        (((~0ULL) - (1ULL << (l)) + 1) & \
  27         (~0ULL >> (BITS_PER_LONG_LONG - 1 - (h))))
  28
  29extern unsigned int __sw_hweight8(unsigned int w);
  30extern unsigned int __sw_hweight16(unsigned int w);
  31extern unsigned int __sw_hweight32(unsigned int w);
  32extern unsigned long __sw_hweight64(__u64 w);
  33
  34/*
  35 * Include this here because some architectures need generic_ffs/fls in
  36 * scope
  37 */
  38#include <asm/bitops.h>
  39
  40#define for_each_set_bit(bit, addr, size) \
  41        for ((bit) = find_first_bit((addr), (size));            \
  42             (bit) < (size);                                    \
  43             (bit) = find_next_bit((addr), (size), (bit) + 1))
  44
  45/* same as for_each_set_bit() but use bit as value to start with */
  46#define for_each_set_bit_from(bit, addr, size) \
  47        for ((bit) = find_next_bit((addr), (size), (bit));      \
  48             (bit) < (size);                                    \
  49             (bit) = find_next_bit((addr), (size), (bit) + 1))
  50
  51#define for_each_clear_bit(bit, addr, size) \
  52        for ((bit) = find_first_zero_bit((addr), (size));       \
  53             (bit) < (size);                                    \
  54             (bit) = find_next_zero_bit((addr), (size), (bit) + 1))
  55
  56/* same as for_each_clear_bit() but use bit as value to start with */
  57#define for_each_clear_bit_from(bit, addr, size) \
  58        for ((bit) = find_next_zero_bit((addr), (size), (bit)); \
  59             (bit) < (size);                                    \
  60             (bit) = find_next_zero_bit((addr), (size), (bit) + 1))
  61
  62static inline int get_bitmask_order(unsigned int count)
  63{
  64        int order;
  65
  66        order = fls(count);
  67        return order;   /* We could be slightly more clever with -1 here... */
  68}
  69
  70static __always_inline unsigned long hweight_long(unsigned long w)
  71{
  72        return sizeof(w) == 4 ? hweight32(w) : hweight64(w);
  73}
  74
  75/**
  76 * rol64 - rotate a 64-bit value left
  77 * @word: value to rotate
  78 * @shift: bits to roll
  79 */
  80static inline __u64 rol64(__u64 word, unsigned int shift)
  81{
  82        return (word << shift) | (word >> (64 - shift));
  83}
  84
  85/**
  86 * ror64 - rotate a 64-bit value right
  87 * @word: value to rotate
  88 * @shift: bits to roll
  89 */
  90static inline __u64 ror64(__u64 word, unsigned int shift)
  91{
  92        return (word >> shift) | (word << (64 - shift));
  93}
  94
  95/**
  96 * rol32 - rotate a 32-bit value left
  97 * @word: value to rotate
  98 * @shift: bits to roll
  99 */
 100static inline __u32 rol32(__u32 word, unsigned int shift)
 101{
 102        return (word << shift) | (word >> ((-shift) & 31));
 103}
 104
 105/**
 106 * ror32 - rotate a 32-bit value right
 107 * @word: value to rotate
 108 * @shift: bits to roll
 109 */
 110static inline __u32 ror32(__u32 word, unsigned int shift)
 111{
 112        return (word >> shift) | (word << (32 - shift));
 113}
 114
 115/**
 116 * rol16 - rotate a 16-bit value left
 117 * @word: value to rotate
 118 * @shift: bits to roll
 119 */
 120static inline __u16 rol16(__u16 word, unsigned int shift)
 121{
 122        return (word << shift) | (word >> (16 - shift));
 123}
 124
 125/**
 126 * ror16 - rotate a 16-bit value right
 127 * @word: value to rotate
 128 * @shift: bits to roll
 129 */
 130static inline __u16 ror16(__u16 word, unsigned int shift)
 131{
 132        return (word >> shift) | (word << (16 - shift));
 133}
 134
 135/**
 136 * rol8 - rotate an 8-bit value left
 137 * @word: value to rotate
 138 * @shift: bits to roll
 139 */
 140static inline __u8 rol8(__u8 word, unsigned int shift)
 141{
 142        return (word << shift) | (word >> (8 - shift));
 143}
 144
 145/**
 146 * ror8 - rotate an 8-bit value right
 147 * @word: value to rotate
 148 * @shift: bits to roll
 149 */
 150static inline __u8 ror8(__u8 word, unsigned int shift)
 151{
 152        return (word >> shift) | (word << (8 - shift));
 153}
 154
 155/**
 156 * sign_extend32 - sign extend a 32-bit value using specified bit as sign-bit
 157 * @value: value to sign extend
 158 * @index: 0 based bit index (0<=index<32) to sign bit
 159 *
 160 * This is safe to use for 16- and 8-bit types as well.
 161 */
 162static inline __s32 sign_extend32(__u32 value, int index)
 163{
 164        __u8 shift = 31 - index;
 165        return (__s32)(value << shift) >> shift;
 166}
 167
 168/**
 169 * sign_extend64 - sign extend a 64-bit value using specified bit as sign-bit
 170 * @value: value to sign extend
 171 * @index: 0 based bit index (0<=index<64) to sign bit
 172 */
 173static inline __s64 sign_extend64(__u64 value, int index)
 174{
 175        __u8 shift = 63 - index;
 176        return (__s64)(value << shift) >> shift;
 177}
 178
 179static inline unsigned fls_long(unsigned long l)
 180{
 181        if (sizeof(l) == 4)
 182                return fls(l);
 183        return fls64(l);
 184}
 185
 186static inline int get_count_order(unsigned int count)
 187{
 188        int order;
 189
 190        order = fls(count) - 1;
 191        if (count & (count - 1))
 192                order++;
 193        return order;
 194}
 195
 196/**
 197 * get_count_order_long - get order after rounding @l up to power of 2
 198 * @l: parameter
 199 *
 200 * it is same as get_count_order() but with long type parameter
 201 */
 202static inline int get_count_order_long(unsigned long l)
 203{
 204        if (l == 0UL)
 205                return -1;
 206        else if (l & (l - 1UL))
 207                return (int)fls_long(l);
 208        else
 209                return (int)fls_long(l) - 1;
 210}
 211
 212/**
 213 * __ffs64 - find first set bit in a 64 bit word
 214 * @word: The 64 bit word
 215 *
 216 * On 64 bit arches this is a synomyn for __ffs
 217 * The result is not defined if no bits are set, so check that @word
 218 * is non-zero before calling this.
 219 */
 220static inline unsigned long __ffs64(u64 word)
 221{
 222#if BITS_PER_LONG == 32
 223        if (((u32)word) == 0UL)
 224                return __ffs((u32)(word >> 32)) + 32;
 225#elif BITS_PER_LONG != 64
 226#error BITS_PER_LONG not 32 or 64
 227#endif
 228        return __ffs((unsigned long)word);
 229}
 230
 231#ifdef __KERNEL__
 232
 233#ifndef set_mask_bits
 234#define set_mask_bits(ptr, _mask, _bits)        \
 235({                                                              \
 236        const typeof(*ptr) mask = (_mask), bits = (_bits);      \
 237        typeof(*ptr) old, new;                                  \
 238                                                                \
 239        do {                                                    \
 240                old = ACCESS_ONCE(*ptr);                        \
 241                new = (old & ~mask) | bits;                     \
 242        } while (cmpxchg(ptr, old, new) != old);                \
 243                                                                \
 244        new;                                                    \
 245})
 246#endif
 247
 248#ifndef bit_clear_unless
 249#define bit_clear_unless(ptr, _clear, _test)    \
 250({                                                              \
 251        const typeof(*ptr) clear = (_clear), test = (_test);    \
 252        typeof(*ptr) old, new;                                  \
 253                                                                \
 254        do {                                                    \
 255                old = ACCESS_ONCE(*ptr);                        \
 256                new = old & ~clear;                             \
 257        } while (!(old & test) &&                               \
 258                 cmpxchg(ptr, old, new) != old);                \
 259                                                                \
 260        !(old & test);                                          \
 261})
 262#endif
 263
 264#ifndef find_last_bit
 265/**
 266 * find_last_bit - find the last set bit in a memory region
 267 * @addr: The address to start the search at
 268 * @size: The number of bits to search
 269 *
 270 * Returns the bit number of the last set bit, or size.
 271 */
 272extern unsigned long find_last_bit(const unsigned long *addr,
 273                                   unsigned long size);
 274#endif
 275
 276#endif /* __KERNEL__ */
 277#endif
 278