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Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
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 <linux/compiler.h>
20
21/*
22 * Some hacks to defeat gcc over-optimizations..
23 */
24struct __dummy { unsigned long a[100]; };
25#define ADDR (*(struct __dummy *) addr)
26#define CONST_ADDR (*(const struct __dummy *) addr)
27
28/*
29 * set_bit - Atomically set a bit in memory
30 * @nr: the bit to set
31 * @addr: the address to start counting from
32 *
33 * This function is atomic and may not be reordered. See __set_bit()
34 * if you do not require the atomic guarantees.
35 * Note that @nr may be almost arbitrarily large; this function is not
36 * restricted to acting on a single-word quantity.
37 */
38
39#define set_bit(nr, addr) (void)test_and_set_bit(nr, addr)
40
41#define __set_bit(nr, addr) (void)__test_and_set_bit(nr, addr)
42
43/*
44 * clear_bit - Clears a bit in memory
45 * @nr: Bit to clear
46 * @addr: Address to start counting from
47 *
48 * clear_bit() is atomic and may not be reordered. However, it does
49 * not contain a memory barrier, so if it is used for locking purposes,
50 * you should call smp_mb__before_clear_bit() and/or smp_mb__after_clear_bit()
51 * in order to ensure changes are visible on other processors.
52 */
53
54#define clear_bit(nr, addr) (void)test_and_clear_bit(nr, addr)
55
56#define __clear_bit(nr, addr) (void)__test_and_clear_bit(nr, addr)
57
58/*
59 * change_bit - Toggle a bit in memory
60 * @nr: Bit to change
61 * @addr: Address to start counting from
62 *
63 * change_bit() is atomic and may not be reordered.
64 * Note that @nr may be almost arbitrarily large; this function is not
65 * restricted to acting on a single-word quantity.
66 */
67
68#define change_bit(nr, addr) (void)test_and_change_bit(nr, addr)
69
70/*
71 * __change_bit - Toggle a bit in memory
72 * @nr: the bit to change
73 * @addr: the address to start counting from
74 *
75 * Unlike change_bit(), this function is non-atomic and may be reordered.
76 * If it's called on the same region of memory simultaneously, the effect
77 * may be that only one operation succeeds.
78 */
79
80#define __change_bit(nr, addr) (void)__test_and_change_bit(nr, addr)
81
82/**
83 * test_and_set_bit - Set a bit and return its old value
84 * @nr: Bit to set
85 * @addr: Address to count from
86 *
87 * This operation is atomic and cannot be reordered.
88 * It also implies a memory barrier.
89 */
90
91extern inline int test_and_set_bit(int nr, void *addr)
92{
93 unsigned int mask, retval;
94 unsigned long flags;
95 unsigned int *adr = (unsigned int *)addr;
96
97 adr += nr >> 5;
98 mask = 1 << (nr & 0x1f);
99 local_save_flags(flags);
100 local_irq_disable();
101 retval = (mask & *adr) != 0;
102 *adr |= mask;
103 local_irq_restore(flags);
104 return retval;
105}
106
107extern inline int __test_and_set_bit(int nr, void *addr)
108{
109 unsigned int mask, retval;
110 unsigned int *adr = (unsigned int *)addr;
111
112 adr += nr >> 5;
113 mask = 1 << (nr & 0x1f);
114 retval = (mask & *adr) != 0;
115 *adr |= mask;
116 return retval;
117}
118
119/*
120 * clear_bit() doesn't provide any barrier for the compiler.
121 */
122#define smp_mb__before_clear_bit() barrier()
123#define smp_mb__after_clear_bit() barrier()
124
125/**
126 * test_and_clear_bit - Clear a bit and return its old value
127 * @nr: Bit to clear
128 * @addr: Address to count from
129 *
130 * This operation is atomic and cannot be reordered.
131 * It also implies a memory barrier.
132 */
133
134extern inline int test_and_clear_bit(int nr, void *addr)
135{
136 unsigned int mask, retval;
137 unsigned long flags;
138 unsigned int *adr = (unsigned int *)addr;
139
140 adr += nr >> 5;
141 mask = 1 << (nr & 0x1f);
142 local_save_flags(flags);
143 local_irq_disable();
144 retval = (mask & *adr) != 0;
145 *adr &= ~mask;
146 local_irq_restore(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
160extern inline int __test_and_clear_bit(int nr, void *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
180extern inline int test_and_change_bit(int nr, void *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 local_save_flags(flags);
188 local_irq_disable();
189 retval = (mask & *adr) != 0;
190 *adr ^= mask;
191 local_irq_restore(flags);
192 return retval;
193}
194
195/* WARNING: non atomic and it can be reordered! */
196
197extern inline int __test_and_change_bit(int nr, void *addr)
198{
199 unsigned int mask, retval;
200 unsigned int *adr = (unsigned int *)addr;
201
202 adr += nr >> 5;
203 mask = 1 << (nr & 0x1f);
204 retval = (mask & *adr) != 0;
205 *adr ^= mask;
206
207 return retval;
208}
209
210/**
211 * test_bit - Determine whether a bit is set
212 * @nr: bit number to test
213 * @addr: Address to start counting from
214 *
215 * This routine doesn't need to be atomic.
216 */
217
218extern inline int test_bit(int nr, const void *addr)
219{
220 unsigned int mask;
221 unsigned int *adr = (unsigned int *)addr;
222
223 adr += nr >> 5;
224 mask = 1 << (nr & 0x1f);
225 return ((mask & *adr) != 0);
226}
227
228/*
229 * Find-bit routines..
230 */
231
232/*
233 * Since we define it "external", it collides with the built-in
234 * definition, which doesn't have the same semantics. We don't want to
235 * use -fno-builtin, so just hide the name ffs.
236 */
237#define ffs kernel_ffs
238
239/*
240 * fls: find last bit set.
241 */
242
243#define fls(x) generic_fls(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 */
262extern inline int find_next_zero_bit (void * 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(void *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
370extern inline int sched_find_first_bit(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 */