Linux kernel mirror (for testing)
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1/* asm/bitops.h for Linux/CRIS
2 *
3 * TODO: asm versions if speed is needed
4 *
5 * All bit operations return 0 if the bit was cleared before the
6 * operation and != 0 if it was not.
7 *
8 * bit 0 is the LSB of addr; bit 32 is the LSB of (addr+1).
9 */
10
11#ifndef _CRIS_BITOPS_H
12#define _CRIS_BITOPS_H
13
14/* Currently this is unsuitable for consumption outside the kernel. */
15#ifdef __KERNEL__
16
17#include <asm/arch/bitops.h>
18#include <asm/system.h>
19#include <asm/atomic.h>
20#include <linux/compiler.h>
21
22/*
23 * Some hacks to defeat gcc over-optimizations..
24 */
25struct __dummy { unsigned long a[100]; };
26#define ADDR (*(struct __dummy *) addr)
27#define CONST_ADDR (*(const struct __dummy *) addr)
28
29/*
30 * set_bit - Atomically set a bit in memory
31 * @nr: the bit to set
32 * @addr: the address to start counting from
33 *
34 * This function is atomic and may not be reordered. See __set_bit()
35 * if you do not require the atomic guarantees.
36 * Note that @nr may be almost arbitrarily large; this function is not
37 * restricted to acting on a single-word quantity.
38 */
39
40#define set_bit(nr, addr) (void)test_and_set_bit(nr, addr)
41
42#define __set_bit(nr, addr) (void)__test_and_set_bit(nr, addr)
43
44/*
45 * clear_bit - Clears a bit in memory
46 * @nr: Bit to clear
47 * @addr: Address to start counting from
48 *
49 * clear_bit() is atomic and may not be reordered. However, it does
50 * not contain a memory barrier, so if it is used for locking purposes,
51 * you should call smp_mb__before_clear_bit() and/or smp_mb__after_clear_bit()
52 * in order to ensure changes are visible on other processors.
53 */
54
55#define clear_bit(nr, addr) (void)test_and_clear_bit(nr, addr)
56
57#define __clear_bit(nr, addr) (void)__test_and_clear_bit(nr, addr)
58
59/*
60 * change_bit - Toggle a bit in memory
61 * @nr: Bit to change
62 * @addr: Address to start counting from
63 *
64 * change_bit() is atomic and may not be reordered.
65 * Note that @nr may be almost arbitrarily large; this function is not
66 * restricted to acting on a single-word quantity.
67 */
68
69#define change_bit(nr, addr) (void)test_and_change_bit(nr, addr)
70
71/*
72 * __change_bit - Toggle a bit in memory
73 * @nr: the bit to change
74 * @addr: the address to start counting from
75 *
76 * Unlike change_bit(), this function is non-atomic and may be reordered.
77 * If it's called on the same region of memory simultaneously, the effect
78 * may be that only one operation succeeds.
79 */
80
81#define __change_bit(nr, addr) (void)__test_and_change_bit(nr, addr)
82
83/**
84 * test_and_set_bit - Set a bit and return its old value
85 * @nr: Bit to set
86 * @addr: Address to count from
87 *
88 * This operation is atomic and cannot be reordered.
89 * It also implies a memory barrier.
90 */
91
92static inline int test_and_set_bit(int nr, volatile unsigned long *addr)
93{
94 unsigned int mask, retval;
95 unsigned long flags;
96 unsigned int *adr = (unsigned int *)addr;
97
98 adr += nr >> 5;
99 mask = 1 << (nr & 0x1f);
100 cris_atomic_save(addr, flags);
101 retval = (mask & *adr) != 0;
102 *adr |= mask;
103 cris_atomic_restore(addr, flags);
104 local_irq_restore(flags);
105 return retval;
106}
107
108static inline int __test_and_set_bit(int nr, volatile unsigned long *addr)
109{
110 unsigned int mask, retval;
111 unsigned int *adr = (unsigned int *)addr;
112
113 adr += nr >> 5;
114 mask = 1 << (nr & 0x1f);
115 retval = (mask & *adr) != 0;
116 *adr |= mask;
117 return retval;
118}
119
120/*
121 * clear_bit() doesn't provide any barrier for the compiler.
122 */
123#define smp_mb__before_clear_bit() barrier()
124#define smp_mb__after_clear_bit() barrier()
125
126/**
127 * test_and_clear_bit - Clear a bit and return its old value
128 * @nr: Bit to clear
129 * @addr: Address to count from
130 *
131 * This operation is atomic and cannot be reordered.
132 * It also implies a memory barrier.
133 */
134
135static inline int test_and_clear_bit(int nr, volatile unsigned long *addr)
136{
137 unsigned int mask, retval;
138 unsigned long flags;
139 unsigned int *adr = (unsigned int *)addr;
140
141 adr += nr >> 5;
142 mask = 1 << (nr & 0x1f);
143 cris_atomic_save(addr, flags);
144 retval = (mask & *adr) != 0;
145 *adr &= ~mask;
146 cris_atomic_restore(addr, flags);
147 return retval;
148}
149
150/**
151 * __test_and_clear_bit - Clear a bit and return its old value
152 * @nr: Bit to clear
153 * @addr: Address to count from
154 *
155 * This operation is non-atomic and can be reordered.
156 * If two examples of this operation race, one can appear to succeed
157 * but actually fail. You must protect multiple accesses with a lock.
158 */
159
160static inline int __test_and_clear_bit(int nr, volatile unsigned long *addr)
161{
162 unsigned int mask, retval;
163 unsigned int *adr = (unsigned int *)addr;
164
165 adr += nr >> 5;
166 mask = 1 << (nr & 0x1f);
167 retval = (mask & *adr) != 0;
168 *adr &= ~mask;
169 return retval;
170}
171/**
172 * test_and_change_bit - Change a bit and return its old value
173 * @nr: Bit to change
174 * @addr: Address to count from
175 *
176 * This operation is atomic and cannot be reordered.
177 * It also implies a memory barrier.
178 */
179
180static inline int test_and_change_bit(int nr, volatile unsigned long *addr)
181{
182 unsigned int mask, retval;
183 unsigned long flags;
184 unsigned int *adr = (unsigned int *)addr;
185 adr += nr >> 5;
186 mask = 1 << (nr & 0x1f);
187 cris_atomic_save(addr, flags);
188 retval = (mask & *adr) != 0;
189 *adr ^= mask;
190 cris_atomic_restore(addr, flags);
191 return retval;
192}
193
194/* WARNING: non atomic and it can be reordered! */
195
196static inline int __test_and_change_bit(int nr, volatile unsigned long *addr)
197{
198 unsigned int mask, retval;
199 unsigned int *adr = (unsigned int *)addr;
200
201 adr += nr >> 5;
202 mask = 1 << (nr & 0x1f);
203 retval = (mask & *adr) != 0;
204 *adr ^= mask;
205
206 return retval;
207}
208
209/**
210 * test_bit - Determine whether a bit is set
211 * @nr: bit number to test
212 * @addr: Address to start counting from
213 *
214 * This routine doesn't need to be atomic.
215 */
216
217static inline int test_bit(int nr, const volatile unsigned long *addr)
218{
219 unsigned int mask;
220 unsigned int *adr = (unsigned int *)addr;
221
222 adr += nr >> 5;
223 mask = 1 << (nr & 0x1f);
224 return ((mask & *adr) != 0);
225}
226
227/*
228 * Find-bit routines..
229 */
230
231/*
232 * Since we define it "external", it collides with the built-in
233 * definition, which doesn't have the same semantics. We don't want to
234 * use -fno-builtin, so just hide the name ffs.
235 */
236#define ffs kernel_ffs
237
238/*
239 * fls: find last bit set.
240 */
241
242#define fls(x) generic_fls(x)
243#define fls64(x) generic_fls64(x)
244
245/*
246 * hweightN - returns the hamming weight of a N-bit word
247 * @x: the word to weigh
248 *
249 * The Hamming Weight of a number is the total number of bits set in it.
250 */
251
252#define hweight32(x) generic_hweight32(x)
253#define hweight16(x) generic_hweight16(x)
254#define hweight8(x) generic_hweight8(x)
255
256/**
257 * find_next_zero_bit - find the first zero bit in a memory region
258 * @addr: The address to base the search on
259 * @offset: The bitnumber to start searching at
260 * @size: The maximum size to search
261 */
262static inline int find_next_zero_bit (const unsigned long * addr, int size, int offset)
263{
264 unsigned long *p = ((unsigned long *) addr) + (offset >> 5);
265 unsigned long result = offset & ~31UL;
266 unsigned long tmp;
267
268 if (offset >= size)
269 return size;
270 size -= result;
271 offset &= 31UL;
272 if (offset) {
273 tmp = *(p++);
274 tmp |= ~0UL >> (32-offset);
275 if (size < 32)
276 goto found_first;
277 if (~tmp)
278 goto found_middle;
279 size -= 32;
280 result += 32;
281 }
282 while (size & ~31UL) {
283 if (~(tmp = *(p++)))
284 goto found_middle;
285 result += 32;
286 size -= 32;
287 }
288 if (!size)
289 return result;
290 tmp = *p;
291
292 found_first:
293 tmp |= ~0UL >> size;
294 found_middle:
295 return result + ffz(tmp);
296}
297
298/**
299 * find_next_bit - find the first set bit in a memory region
300 * @addr: The address to base the search on
301 * @offset: The bitnumber to start searching at
302 * @size: The maximum size to search
303 */
304static __inline__ int find_next_bit(const unsigned long *addr, int size, int offset)
305{
306 unsigned long *p = ((unsigned long *) addr) + (offset >> 5);
307 unsigned long result = offset & ~31UL;
308 unsigned long tmp;
309
310 if (offset >= size)
311 return size;
312 size -= result;
313 offset &= 31UL;
314 if (offset) {
315 tmp = *(p++);
316 tmp &= (~0UL << offset);
317 if (size < 32)
318 goto found_first;
319 if (tmp)
320 goto found_middle;
321 size -= 32;
322 result += 32;
323 }
324 while (size & ~31UL) {
325 if ((tmp = *(p++)))
326 goto found_middle;
327 result += 32;
328 size -= 32;
329 }
330 if (!size)
331 return result;
332 tmp = *p;
333
334found_first:
335 tmp &= (~0UL >> (32 - size));
336 if (tmp == 0UL) /* Are any bits set? */
337 return result + size; /* Nope. */
338found_middle:
339 return result + __ffs(tmp);
340}
341
342/**
343 * find_first_zero_bit - find the first zero bit in a memory region
344 * @addr: The address to start the search at
345 * @size: The maximum size to search
346 *
347 * Returns the bit-number of the first zero bit, not the number of the byte
348 * containing a bit.
349 */
350
351#define find_first_zero_bit(addr, size) \
352 find_next_zero_bit((addr), (size), 0)
353#define find_first_bit(addr, size) \
354 find_next_bit((addr), (size), 0)
355
356#define ext2_set_bit test_and_set_bit
357#define ext2_set_bit_atomic(l,n,a) test_and_set_bit(n,a)
358#define ext2_clear_bit test_and_clear_bit
359#define ext2_clear_bit_atomic(l,n,a) test_and_clear_bit(n,a)
360#define ext2_test_bit test_bit
361#define ext2_find_first_zero_bit find_first_zero_bit
362#define ext2_find_next_zero_bit find_next_zero_bit
363
364/* Bitmap functions for the minix filesystem. */
365#define minix_set_bit(nr,addr) test_and_set_bit(nr,addr)
366#define minix_clear_bit(nr,addr) test_and_clear_bit(nr,addr)
367#define minix_test_bit(nr,addr) test_bit(nr,addr)
368#define minix_find_first_zero_bit(addr,size) find_first_zero_bit(addr,size)
369
370static inline int sched_find_first_bit(const unsigned long *b)
371{
372 if (unlikely(b[0]))
373 return __ffs(b[0]);
374 if (unlikely(b[1]))
375 return __ffs(b[1]) + 32;
376 if (unlikely(b[2]))
377 return __ffs(b[2]) + 64;
378 if (unlikely(b[3]))
379 return __ffs(b[3]) + 96;
380 if (b[4])
381 return __ffs(b[4]) + 128;
382 return __ffs(b[5]) + 32 + 128;
383}
384
385#endif /* __KERNEL__ */
386
387#endif /* _CRIS_BITOPS_H */