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TOMOYO Linux Cross Reference
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_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 find_last_bit
231 /**
232  * find_last_bit - find the last set bit in a memory region
233  * @addr: The address to start the search at
234  * @size: The number of bits to search
235  *
236  * Returns the bit number of the last set bit, or size.
237  */
238 extern unsigned long find_last_bit(const unsigned long *addr,
239                                    unsigned long size);
240 #endif
241 
242 #endif /* __KERNEL__ */
243 #endif
244 

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