Linux kernel mirror (for testing)
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1/*
2 * Copyright 1995, Russell King.
3 *
4 * Based on the arm32 version by RMK (and others). Their copyrights apply to
5 * Those parts.
6 * Modified for arm26 by Ian Molton on 25/11/04
7 *
8 * bit 0 is the LSB of an "unsigned long" quantity.
9 *
10 * Please note that the code in this file should never be included
11 * from user space. Many of these are not implemented in assembler
12 * since they would be too costly. Also, they require privileged
13 * instructions (which are not available from user mode) to ensure
14 * that they are atomic.
15 */
16
17#ifndef __ASM_ARM_BITOPS_H
18#define __ASM_ARM_BITOPS_H
19
20#ifdef __KERNEL__
21
22#include <linux/compiler.h>
23#include <asm/system.h>
24
25#define smp_mb__before_clear_bit() do { } while (0)
26#define smp_mb__after_clear_bit() do { } while (0)
27
28/*
29 * These functions are the basis of our bit ops.
30 *
31 * First, the atomic bitops. These use native endian.
32 */
33static inline void ____atomic_set_bit(unsigned int bit, volatile unsigned long *p)
34{
35 unsigned long flags;
36 unsigned long mask = 1UL << (bit & 31);
37
38 p += bit >> 5;
39
40 local_irq_save(flags);
41 *p |= mask;
42 local_irq_restore(flags);
43}
44
45static inline void ____atomic_clear_bit(unsigned int bit, volatile unsigned long *p)
46{
47 unsigned long flags;
48 unsigned long mask = 1UL << (bit & 31);
49
50 p += bit >> 5;
51
52 local_irq_save(flags);
53 *p &= ~mask;
54 local_irq_restore(flags);
55}
56
57static inline void ____atomic_change_bit(unsigned int bit, volatile unsigned long *p)
58{
59 unsigned long flags;
60 unsigned long mask = 1UL << (bit & 31);
61
62 p += bit >> 5;
63
64 local_irq_save(flags);
65 *p ^= mask;
66 local_irq_restore(flags);
67}
68
69static inline int
70____atomic_test_and_set_bit(unsigned int bit, volatile unsigned long *p)
71{
72 unsigned long flags;
73 unsigned int res;
74 unsigned long mask = 1UL << (bit & 31);
75
76 p += bit >> 5;
77
78 local_irq_save(flags);
79 res = *p;
80 *p = res | mask;
81 local_irq_restore(flags);
82
83 return res & mask;
84}
85
86static inline int
87____atomic_test_and_clear_bit(unsigned int bit, volatile unsigned long *p)
88{
89 unsigned long flags;
90 unsigned int res;
91 unsigned long mask = 1UL << (bit & 31);
92
93 p += bit >> 5;
94
95 local_irq_save(flags);
96 res = *p;
97 *p = res & ~mask;
98 local_irq_restore(flags);
99
100 return res & mask;
101}
102
103static inline int
104____atomic_test_and_change_bit(unsigned int bit, volatile unsigned long *p)
105{
106 unsigned long flags;
107 unsigned int res;
108 unsigned long mask = 1UL << (bit & 31);
109
110 p += bit >> 5;
111
112 local_irq_save(flags);
113 res = *p;
114 *p = res ^ mask;
115 local_irq_restore(flags);
116
117 return res & mask;
118}
119
120/*
121 * Now the non-atomic variants. We let the compiler handle all
122 * optimisations for these. These are all _native_ endian.
123 */
124static inline void __set_bit(int nr, volatile unsigned long *p)
125{
126 p[nr >> 5] |= (1UL << (nr & 31));
127}
128
129static inline void __clear_bit(int nr, volatile unsigned long *p)
130{
131 p[nr >> 5] &= ~(1UL << (nr & 31));
132}
133
134static inline void __change_bit(int nr, volatile unsigned long *p)
135{
136 p[nr >> 5] ^= (1UL << (nr & 31));
137}
138
139static inline int __test_and_set_bit(int nr, volatile unsigned long *p)
140{
141 unsigned long oldval, mask = 1UL << (nr & 31);
142
143 p += nr >> 5;
144
145 oldval = *p;
146 *p = oldval | mask;
147 return oldval & mask;
148}
149
150static inline int __test_and_clear_bit(int nr, volatile unsigned long *p)
151{
152 unsigned long oldval, mask = 1UL << (nr & 31);
153
154 p += nr >> 5;
155
156 oldval = *p;
157 *p = oldval & ~mask;
158 return oldval & mask;
159}
160
161static inline int __test_and_change_bit(int nr, volatile unsigned long *p)
162{
163 unsigned long oldval, mask = 1UL << (nr & 31);
164
165 p += nr >> 5;
166
167 oldval = *p;
168 *p = oldval ^ mask;
169 return oldval & mask;
170}
171
172/*
173 * This routine doesn't need to be atomic.
174 */
175static inline int __test_bit(int nr, const volatile unsigned long * p)
176{
177 return (p[nr >> 5] >> (nr & 31)) & 1UL;
178}
179
180/*
181 * Little endian assembly bitops. nr = 0 -> byte 0 bit 0.
182 */
183extern void _set_bit_le(int nr, volatile unsigned long * p);
184extern void _clear_bit_le(int nr, volatile unsigned long * p);
185extern void _change_bit_le(int nr, volatile unsigned long * p);
186extern int _test_and_set_bit_le(int nr, volatile unsigned long * p);
187extern int _test_and_clear_bit_le(int nr, volatile unsigned long * p);
188extern int _test_and_change_bit_le(int nr, volatile unsigned long * p);
189extern int _find_first_zero_bit_le(const unsigned long * p, unsigned size);
190extern int _find_next_zero_bit_le(void * p, int size, int offset);
191extern int _find_first_bit_le(const unsigned long *p, unsigned size);
192extern int _find_next_bit_le(const unsigned long *p, int size, int offset);
193
194/*
195 * The __* form of bitops are non-atomic and may be reordered.
196 */
197#define ATOMIC_BITOP_LE(name,nr,p) \
198 (__builtin_constant_p(nr) ? \
199 ____atomic_##name(nr, p) : \
200 _##name##_le(nr,p))
201
202#define NONATOMIC_BITOP(name,nr,p) \
203 (____nonatomic_##name(nr, p))
204
205/*
206 * These are the little endian, atomic definitions.
207 */
208#define set_bit(nr,p) ATOMIC_BITOP_LE(set_bit,nr,p)
209#define clear_bit(nr,p) ATOMIC_BITOP_LE(clear_bit,nr,p)
210#define change_bit(nr,p) ATOMIC_BITOP_LE(change_bit,nr,p)
211#define test_and_set_bit(nr,p) ATOMIC_BITOP_LE(test_and_set_bit,nr,p)
212#define test_and_clear_bit(nr,p) ATOMIC_BITOP_LE(test_and_clear_bit,nr,p)
213#define test_and_change_bit(nr,p) ATOMIC_BITOP_LE(test_and_change_bit,nr,p)
214#define test_bit(nr,p) __test_bit(nr,p)
215#define find_first_zero_bit(p,sz) _find_first_zero_bit_le(p,sz)
216#define find_next_zero_bit(p,sz,off) _find_next_zero_bit_le(p,sz,off)
217#define find_first_bit(p,sz) _find_first_bit_le(p,sz)
218#define find_next_bit(p,sz,off) _find_next_bit_le(p,sz,off)
219
220#define WORD_BITOFF_TO_LE(x) ((x))
221
222/*
223 * ffz = Find First Zero in word. Undefined if no zero exists,
224 * so code should check against ~0UL first..
225 */
226static inline unsigned long ffz(unsigned long word)
227{
228 int k;
229
230 word = ~word;
231 k = 31;
232 if (word & 0x0000ffff) { k -= 16; word <<= 16; }
233 if (word & 0x00ff0000) { k -= 8; word <<= 8; }
234 if (word & 0x0f000000) { k -= 4; word <<= 4; }
235 if (word & 0x30000000) { k -= 2; word <<= 2; }
236 if (word & 0x40000000) { k -= 1; }
237 return k;
238}
239
240/*
241 * ffz = Find First Zero in word. Undefined if no zero exists,
242 * so code should check against ~0UL first..
243 */
244static inline unsigned long __ffs(unsigned long word)
245{
246 int k;
247
248 k = 31;
249 if (word & 0x0000ffff) { k -= 16; word <<= 16; }
250 if (word & 0x00ff0000) { k -= 8; word <<= 8; }
251 if (word & 0x0f000000) { k -= 4; word <<= 4; }
252 if (word & 0x30000000) { k -= 2; word <<= 2; }
253 if (word & 0x40000000) { k -= 1; }
254 return k;
255}
256
257/*
258 * fls: find last bit set.
259 */
260
261#define fls(x) generic_fls(x)
262#define fls64(x) generic_fls64(x)
263
264/*
265 * ffs: find first bit set. This is defined the same way as
266 * the libc and compiler builtin ffs routines, therefore
267 * differs in spirit from the above ffz (man ffs).
268 */
269
270#define ffs(x) generic_ffs(x)
271
272/*
273 * Find first bit set in a 168-bit bitmap, where the first
274 * 128 bits are unlikely to be set.
275 */
276static inline int sched_find_first_bit(unsigned long *b)
277{
278 unsigned long v;
279 unsigned int off;
280
281 for (off = 0; v = b[off], off < 4; off++) {
282 if (unlikely(v))
283 break;
284 }
285 return __ffs(v) + off * 32;
286}
287
288/*
289 * hweightN: returns the hamming weight (i.e. the number
290 * of bits set) of a N-bit word
291 */
292
293#define hweight32(x) generic_hweight32(x)
294#define hweight16(x) generic_hweight16(x)
295#define hweight8(x) generic_hweight8(x)
296
297/*
298 * Ext2 is defined to use little-endian byte ordering.
299 * These do not need to be atomic.
300 */
301#define ext2_set_bit(nr,p) \
302 __test_and_set_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
303#define ext2_set_bit_atomic(lock,nr,p) \
304 test_and_set_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
305#define ext2_clear_bit(nr,p) \
306 __test_and_clear_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
307#define ext2_clear_bit_atomic(lock,nr,p) \
308 test_and_clear_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
309#define ext2_test_bit(nr,p) \
310 __test_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
311#define ext2_find_first_zero_bit(p,sz) \
312 _find_first_zero_bit_le(p,sz)
313#define ext2_find_next_zero_bit(p,sz,off) \
314 _find_next_zero_bit_le(p,sz,off)
315
316/*
317 * Minix is defined to use little-endian byte ordering.
318 * These do not need to be atomic.
319 */
320#define minix_set_bit(nr,p) \
321 __set_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
322#define minix_test_bit(nr,p) \
323 __test_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
324#define minix_test_and_set_bit(nr,p) \
325 __test_and_set_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
326#define minix_test_and_clear_bit(nr,p) \
327 __test_and_clear_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
328#define minix_find_first_zero_bit(p,sz) \
329 _find_first_zero_bit_le((unsigned long *)(p),sz)
330
331#endif /* __KERNEL__ */
332
333#endif /* _ARM_BITOPS_H */