xref: /linux-6.15/include/linux/bitops.h (revision e756bc56)
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)		(((U32_C(1) << ((h) - (l) + 1)) - 1) << (l))
22 #define GENMASK_ULL(h, l)	(((U64_C(1) << ((h) - (l) + 1)) - 1) << (l))
23 
24 extern unsigned int __sw_hweight8(unsigned int w);
25 extern unsigned int __sw_hweight16(unsigned int w);
26 extern unsigned int __sw_hweight32(unsigned int w);
27 extern unsigned long __sw_hweight64(__u64 w);
28 
29 /*
30  * Include this here because some architectures need generic_ffs/fls in
31  * scope
32  */
33 #include <asm/bitops.h>
34 
35 #define for_each_set_bit(bit, addr, size) \
36 	for ((bit) = find_first_bit((addr), (size));		\
37 	     (bit) < (size);					\
38 	     (bit) = find_next_bit((addr), (size), (bit) + 1))
39 
40 /* same as for_each_set_bit() but use bit as value to start with */
41 #define for_each_set_bit_from(bit, addr, size) \
42 	for ((bit) = find_next_bit((addr), (size), (bit));	\
43 	     (bit) < (size);					\
44 	     (bit) = find_next_bit((addr), (size), (bit) + 1))
45 
46 #define for_each_clear_bit(bit, addr, size) \
47 	for ((bit) = find_first_zero_bit((addr), (size));	\
48 	     (bit) < (size);					\
49 	     (bit) = find_next_zero_bit((addr), (size), (bit) + 1))
50 
51 /* same as for_each_clear_bit() but use bit as value to start with */
52 #define for_each_clear_bit_from(bit, addr, size) \
53 	for ((bit) = find_next_zero_bit((addr), (size), (bit));	\
54 	     (bit) < (size);					\
55 	     (bit) = find_next_zero_bit((addr), (size), (bit) + 1))
56 
57 static __inline__ int get_bitmask_order(unsigned int count)
58 {
59 	int order;
60 
61 	order = fls(count);
62 	return order;	/* We could be slightly more clever with -1 here... */
63 }
64 
65 static __inline__ int get_count_order(unsigned int count)
66 {
67 	int order;
68 
69 	order = fls(count) - 1;
70 	if (count & (count - 1))
71 		order++;
72 	return order;
73 }
74 
75 static inline unsigned long hweight_long(unsigned long w)
76 {
77 	return sizeof(w) == 4 ? hweight32(w) : hweight64(w);
78 }
79 
80 /**
81  * rol64 - rotate a 64-bit value left
82  * @word: value to rotate
83  * @shift: bits to roll
84  */
85 static inline __u64 rol64(__u64 word, unsigned int shift)
86 {
87 	return (word << shift) | (word >> (64 - shift));
88 }
89 
90 /**
91  * ror64 - rotate a 64-bit value right
92  * @word: value to rotate
93  * @shift: bits to roll
94  */
95 static inline __u64 ror64(__u64 word, unsigned int shift)
96 {
97 	return (word >> shift) | (word << (64 - shift));
98 }
99 
100 /**
101  * rol32 - rotate a 32-bit value left
102  * @word: value to rotate
103  * @shift: bits to roll
104  */
105 static inline __u32 rol32(__u32 word, unsigned int shift)
106 {
107 	return (word << shift) | (word >> (32 - shift));
108 }
109 
110 /**
111  * ror32 - rotate a 32-bit value right
112  * @word: value to rotate
113  * @shift: bits to roll
114  */
115 static inline __u32 ror32(__u32 word, unsigned int shift)
116 {
117 	return (word >> shift) | (word << (32 - shift));
118 }
119 
120 /**
121  * rol16 - rotate a 16-bit value left
122  * @word: value to rotate
123  * @shift: bits to roll
124  */
125 static inline __u16 rol16(__u16 word, unsigned int shift)
126 {
127 	return (word << shift) | (word >> (16 - shift));
128 }
129 
130 /**
131  * ror16 - rotate a 16-bit value right
132  * @word: value to rotate
133  * @shift: bits to roll
134  */
135 static inline __u16 ror16(__u16 word, unsigned int shift)
136 {
137 	return (word >> shift) | (word << (16 - shift));
138 }
139 
140 /**
141  * rol8 - rotate an 8-bit value left
142  * @word: value to rotate
143  * @shift: bits to roll
144  */
145 static inline __u8 rol8(__u8 word, unsigned int shift)
146 {
147 	return (word << shift) | (word >> (8 - shift));
148 }
149 
150 /**
151  * ror8 - rotate an 8-bit value right
152  * @word: value to rotate
153  * @shift: bits to roll
154  */
155 static inline __u8 ror8(__u8 word, unsigned int shift)
156 {
157 	return (word >> shift) | (word << (8 - shift));
158 }
159 
160 /**
161  * sign_extend32 - sign extend a 32-bit value using specified bit as sign-bit
162  * @value: value to sign extend
163  * @index: 0 based bit index (0<=index<32) to sign bit
164  */
165 static inline __s32 sign_extend32(__u32 value, int index)
166 {
167 	__u8 shift = 31 - index;
168 	return (__s32)(value << shift) >> shift;
169 }
170 
171 static inline unsigned fls_long(unsigned long l)
172 {
173 	if (sizeof(l) == 4)
174 		return fls(l);
175 	return fls64(l);
176 }
177 
178 /**
179  * __ffs64 - find first set bit in a 64 bit word
180  * @word: The 64 bit word
181  *
182  * On 64 bit arches this is a synomyn for __ffs
183  * The result is not defined if no bits are set, so check that @word
184  * is non-zero before calling this.
185  */
186 static inline unsigned long __ffs64(u64 word)
187 {
188 #if BITS_PER_LONG == 32
189 	if (((u32)word) == 0UL)
190 		return __ffs((u32)(word >> 32)) + 32;
191 #elif BITS_PER_LONG != 64
192 #error BITS_PER_LONG not 32 or 64
193 #endif
194 	return __ffs((unsigned long)word);
195 }
196 
197 #ifdef __KERNEL__
198 
199 #ifndef find_last_bit
200 /**
201  * find_last_bit - find the last set bit in a memory region
202  * @addr: The address to start the search at
203  * @size: The maximum size to search
204  *
205  * Returns the bit number of the first set bit, or size.
206  */
207 extern unsigned long find_last_bit(const unsigned long *addr,
208 				   unsigned long size);
209 #endif
210 
211 #endif /* __KERNEL__ */
212 #endif
213