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[cris-mirror.git] / include / asm-arm26 / bitops.h
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1 /*
2 * Copyright 1995, Russell King.
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
8 * bit 0 is the LSB of an "unsigned long" quantity.
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.
17 #ifndef __ASM_ARM_BITOPS_H
18 #define __ASM_ARM_BITOPS_H
20 #ifdef __KERNEL__
22 #include <linux/compiler.h>
23 #include <asm/system.h>
25 #define smp_mb__before_clear_bit() do { } while (0)
26 #define smp_mb__after_clear_bit() do { } while (0)
29 * These functions are the basis of our bit ops.
31 * First, the atomic bitops. These use native endian.
33 static inline void ____atomic_set_bit(unsigned int bit, volatile unsigned long *p)
35 unsigned long flags;
36 unsigned long mask = 1UL << (bit & 31);
38 p += bit >> 5;
40 local_irq_save(flags);
41 *p |= mask;
42 local_irq_restore(flags);
45 static inline void ____atomic_clear_bit(unsigned int bit, volatile unsigned long *p)
47 unsigned long flags;
48 unsigned long mask = 1UL << (bit & 31);
50 p += bit >> 5;
52 local_irq_save(flags);
53 *p &= ~mask;
54 local_irq_restore(flags);
57 static inline void ____atomic_change_bit(unsigned int bit, volatile unsigned long *p)
59 unsigned long flags;
60 unsigned long mask = 1UL << (bit & 31);
62 p += bit >> 5;
64 local_irq_save(flags);
65 *p ^= mask;
66 local_irq_restore(flags);
69 static inline int
70 ____atomic_test_and_set_bit(unsigned int bit, volatile unsigned long *p)
72 unsigned long flags;
73 unsigned int res;
74 unsigned long mask = 1UL << (bit & 31);
76 p += bit >> 5;
78 local_irq_save(flags);
79 res = *p;
80 *p = res | mask;
81 local_irq_restore(flags);
83 return res & mask;
86 static inline int
87 ____atomic_test_and_clear_bit(unsigned int bit, volatile unsigned long *p)
89 unsigned long flags;
90 unsigned int res;
91 unsigned long mask = 1UL << (bit & 31);
93 p += bit >> 5;
95 local_irq_save(flags);
96 res = *p;
97 *p = res & ~mask;
98 local_irq_restore(flags);
100 return res & mask;
103 static inline int
104 ____atomic_test_and_change_bit(unsigned int bit, volatile unsigned long *p)
106 unsigned long flags;
107 unsigned int res;
108 unsigned long mask = 1UL << (bit & 31);
110 p += bit >> 5;
112 local_irq_save(flags);
113 res = *p;
114 *p = res ^ mask;
115 local_irq_restore(flags);
117 return res & mask;
121 * Now the non-atomic variants. We let the compiler handle all
122 * optimisations for these. These are all _native_ endian.
124 static inline void __set_bit(int nr, volatile unsigned long *p)
126 p[nr >> 5] |= (1UL << (nr & 31));
129 static inline void __clear_bit(int nr, volatile unsigned long *p)
131 p[nr >> 5] &= ~(1UL << (nr & 31));
134 static inline void __change_bit(int nr, volatile unsigned long *p)
136 p[nr >> 5] ^= (1UL << (nr & 31));
139 static inline int __test_and_set_bit(int nr, volatile unsigned long *p)
141 unsigned long oldval, mask = 1UL << (nr & 31);
143 p += nr >> 5;
145 oldval = *p;
146 *p = oldval | mask;
147 return oldval & mask;
150 static inline int __test_and_clear_bit(int nr, volatile unsigned long *p)
152 unsigned long oldval, mask = 1UL << (nr & 31);
154 p += nr >> 5;
156 oldval = *p;
157 *p = oldval & ~mask;
158 return oldval & mask;
161 static inline int __test_and_change_bit(int nr, volatile unsigned long *p)
163 unsigned long oldval, mask = 1UL << (nr & 31);
165 p += nr >> 5;
167 oldval = *p;
168 *p = oldval ^ mask;
169 return oldval & mask;
173 * This routine doesn't need to be atomic.
175 static inline int __test_bit(int nr, const volatile unsigned long * p)
177 return (p[nr >> 5] >> (nr & 31)) & 1UL;
181 * Little endian assembly bitops. nr = 0 -> byte 0 bit 0.
183 extern void _set_bit_le(int nr, volatile unsigned long * p);
184 extern void _clear_bit_le(int nr, volatile unsigned long * p);
185 extern void _change_bit_le(int nr, volatile unsigned long * p);
186 extern int _test_and_set_bit_le(int nr, volatile unsigned long * p);
187 extern int _test_and_clear_bit_le(int nr, volatile unsigned long * p);
188 extern int _test_and_change_bit_le(int nr, volatile unsigned long * p);
189 extern int _find_first_zero_bit_le(void * p, unsigned size);
190 extern int _find_next_zero_bit_le(void * p, int size, int offset);
191 extern int _find_first_bit_le(const unsigned long *p, unsigned size);
192 extern int _find_next_bit_le(const unsigned long *p, int size, int offset);
195 * The __* form of bitops are non-atomic and may be reordered.
197 #define ATOMIC_BITOP_LE(name,nr,p) \
198 (__builtin_constant_p(nr) ? \
199 ____atomic_##name(nr, p) : \
200 _##name##_le(nr,p))
202 #define NONATOMIC_BITOP(name,nr,p) \
203 (____nonatomic_##name(nr, p))
206 * These are the little endian, atomic definitions.
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)
220 #define WORD_BITOFF_TO_LE(x) ((x))
223 * ffz = Find First Zero in word. Undefined if no zero exists,
224 * so code should check against ~0UL first..
226 static inline unsigned long ffz(unsigned long word)
228 int k;
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;
241 * ffz = Find First Zero in word. Undefined if no zero exists,
242 * so code should check against ~0UL first..
244 static inline unsigned long __ffs(unsigned long word)
246 int k;
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;
258 * fls: find last bit set.
261 #define fls(x) generic_fls(x)
264 * ffs: find first bit set. This is defined the same way as
265 * the libc and compiler builtin ffs routines, therefore
266 * differs in spirit from the above ffz (man ffs).
269 #define ffs(x) generic_ffs(x)
272 * Find first bit set in a 168-bit bitmap, where the first
273 * 128 bits are unlikely to be set.
275 static inline int sched_find_first_bit(unsigned long *b)
277 unsigned long v;
278 unsigned int off;
280 for (off = 0; v = b[off], off < 4; off++) {
281 if (unlikely(v))
282 break;
284 return __ffs(v) + off * 32;
288 * hweightN: returns the hamming weight (i.e. the number
289 * of bits set) of a N-bit word
292 #define hweight32(x) generic_hweight32(x)
293 #define hweight16(x) generic_hweight16(x)
294 #define hweight8(x) generic_hweight8(x)
297 * Ext2 is defined to use little-endian byte ordering.
298 * These do not need to be atomic.
300 #define ext2_set_bit(nr,p) \
301 __test_and_set_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
302 #define ext2_set_bit_atomic(lock,nr,p) \
303 test_and_set_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
304 #define ext2_clear_bit(nr,p) \
305 __test_and_clear_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
306 #define ext2_clear_bit_atomic(lock,nr,p) \
307 test_and_clear_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
308 #define ext2_test_bit(nr,p) \
309 __test_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
310 #define ext2_find_first_zero_bit(p,sz) \
311 _find_first_zero_bit_le(p,sz)
312 #define ext2_find_next_zero_bit(p,sz,off) \
313 _find_next_zero_bit_le(p,sz,off)
316 * Minix is defined to use little-endian byte ordering.
317 * These do not need to be atomic.
319 #define minix_set_bit(nr,p) \
320 __set_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
321 #define minix_test_bit(nr,p) \
322 __test_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
323 #define minix_test_and_set_bit(nr,p) \
324 __test_and_set_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
325 #define minix_test_and_clear_bit(nr,p) \
326 __test_and_clear_bit(WORD_BITOFF_TO_LE(nr), (unsigned long *)(p))
327 #define minix_find_first_zero_bit(p,sz) \
328 _find_first_zero_bit_le(p,sz)
330 #endif /* __KERNEL__ */
332 #endif /* _ARM_BITOPS_H */