1 #ifndef _ALPHA_BITOPS_H
2 #define _ALPHA_BITOPS_H
3
4 #include <linux/config.h>
5 #include <linux/kernel.h>
6
7 /*
8 * Copyright 1994, Linus Torvalds.
9 */
10
11 /*
12 * These have to be done with inline assembly: that way the bit-setting
13 * is guaranteed to be atomic. All bit operations return 0 if the bit
14 * was cleared before the operation and != 0 if it was not.
15 *
16 * To get proper branch prediction for the main line, we must branch
17 * forward to code at the end of this object's .text section, then
18 * branch back to restart the operation.
19 *
20 * bit 0 is the LSB of addr; bit 64 is the LSB of (addr+1).
21 */
22
23 static inline void
set_bit(unsigned long nr,volatile void * addr)24 set_bit(unsigned long nr, volatile void * addr)
25 {
26 unsigned long temp;
27 int *m = ((int *) addr) + (nr >> 5);
28
29 __asm__ __volatile__(
30 "1: ldl_l %0,%3\n"
31 " bis %0,%2,%0\n"
32 " stl_c %0,%1\n"
33 " beq %0,2f\n"
34 ".subsection 2\n"
35 "2: br 1b\n"
36 ".previous"
37 :"=&r" (temp), "=m" (*m)
38 :"Ir" (1UL << (nr & 31)), "m" (*m));
39 }
40
41 /*
42 * WARNING: non atomic version.
43 */
44 static inline void
__set_bit(unsigned long nr,volatile void * addr)45 __set_bit(unsigned long nr, volatile void * addr)
46 {
47 int *m = ((int *) addr) + (nr >> 5);
48
49 *m |= 1 << (nr & 31);
50 }
51
52 #define smp_mb__before_clear_bit() smp_mb()
53 #define smp_mb__after_clear_bit() smp_mb()
54
55 static inline void
clear_bit(unsigned long nr,volatile void * addr)56 clear_bit(unsigned long nr, volatile void * addr)
57 {
58 unsigned long temp;
59 int *m = ((int *) addr) + (nr >> 5);
60
61 __asm__ __volatile__(
62 "1: ldl_l %0,%3\n"
63 " and %0,%2,%0\n"
64 " stl_c %0,%1\n"
65 " beq %0,2f\n"
66 ".subsection 2\n"
67 "2: br 1b\n"
68 ".previous"
69 :"=&r" (temp), "=m" (*m)
70 :"Ir" (~(1UL << (nr & 31))), "m" (*m));
71 }
72
73 /*
74 * WARNING: non atomic version.
75 */
76 static __inline__ void
__change_bit(unsigned long nr,volatile void * addr)77 __change_bit(unsigned long nr, volatile void * addr)
78 {
79 int *m = ((int *) addr) + (nr >> 5);
80
81 *m ^= 1 << (nr & 31);
82 }
83
84 static inline void
change_bit(unsigned long nr,volatile void * addr)85 change_bit(unsigned long nr, volatile void * addr)
86 {
87 unsigned long temp;
88 int *m = ((int *) addr) + (nr >> 5);
89
90 __asm__ __volatile__(
91 "1: ldl_l %0,%3\n"
92 " xor %0,%2,%0\n"
93 " stl_c %0,%1\n"
94 " beq %0,2f\n"
95 ".subsection 2\n"
96 "2: br 1b\n"
97 ".previous"
98 :"=&r" (temp), "=m" (*m)
99 :"Ir" (1UL << (nr & 31)), "m" (*m));
100 }
101
102 static inline int
test_and_set_bit(unsigned long nr,volatile void * addr)103 test_and_set_bit(unsigned long nr, volatile void *addr)
104 {
105 unsigned long oldbit;
106 unsigned long temp;
107 int *m = ((int *) addr) + (nr >> 5);
108
109 __asm__ __volatile__(
110 "1: ldl_l %0,%4\n"
111 " and %0,%3,%2\n"
112 " bne %2,2f\n"
113 " xor %0,%3,%0\n"
114 " stl_c %0,%1\n"
115 " beq %0,3f\n"
116 "2:\n"
117 #ifdef CONFIG_SMP
118 " mb\n"
119 #endif
120 ".subsection 2\n"
121 "3: br 1b\n"
122 ".previous"
123 :"=&r" (temp), "=m" (*m), "=&r" (oldbit)
124 :"Ir" (1UL << (nr & 31)), "m" (*m) : "memory");
125
126 return oldbit != 0;
127 }
128
129 /*
130 * WARNING: non atomic version.
131 */
132 static inline int
__test_and_set_bit(unsigned long nr,volatile void * addr)133 __test_and_set_bit(unsigned long nr, volatile void * addr)
134 {
135 unsigned long mask = 1 << (nr & 0x1f);
136 int *m = ((int *) addr) + (nr >> 5);
137 int old = *m;
138
139 *m = old | mask;
140 return (old & mask) != 0;
141 }
142
143 static inline int
test_and_clear_bit(unsigned long nr,volatile void * addr)144 test_and_clear_bit(unsigned long nr, volatile void * addr)
145 {
146 unsigned long oldbit;
147 unsigned long temp;
148 int *m = ((int *) addr) + (nr >> 5);
149
150 __asm__ __volatile__(
151 "1: ldl_l %0,%4\n"
152 " and %0,%3,%2\n"
153 " beq %2,2f\n"
154 " xor %0,%3,%0\n"
155 " stl_c %0,%1\n"
156 " beq %0,3f\n"
157 "2:\n"
158 #ifdef CONFIG_SMP
159 " mb\n"
160 #endif
161 ".subsection 2\n"
162 "3: br 1b\n"
163 ".previous"
164 :"=&r" (temp), "=m" (*m), "=&r" (oldbit)
165 :"Ir" (1UL << (nr & 31)), "m" (*m) : "memory");
166
167 return oldbit != 0;
168 }
169
170 /*
171 * WARNING: non atomic version.
172 */
173 static inline int
__test_and_clear_bit(unsigned long nr,volatile void * addr)174 __test_and_clear_bit(unsigned long nr, volatile void * addr)
175 {
176 unsigned long mask = 1 << (nr & 0x1f);
177 int *m = ((int *) addr) + (nr >> 5);
178 int old = *m;
179
180 *m = old & ~mask;
181 return (old & mask) != 0;
182 }
183
184 /*
185 * WARNING: non atomic version.
186 */
187 static __inline__ int
__test_and_change_bit(unsigned long nr,volatile void * addr)188 __test_and_change_bit(unsigned long nr, volatile void * addr)
189 {
190 unsigned long mask = 1 << (nr & 0x1f);
191 int *m = ((int *) addr) + (nr >> 5);
192 int old = *m;
193
194 *m = old ^ mask;
195 return (old & mask) != 0;
196 }
197
198 static inline int
test_and_change_bit(unsigned long nr,volatile void * addr)199 test_and_change_bit(unsigned long nr, volatile void * addr)
200 {
201 unsigned long oldbit;
202 unsigned long temp;
203 int *m = ((int *) addr) + (nr >> 5);
204
205 __asm__ __volatile__(
206 "1: ldl_l %0,%4\n"
207 " and %0,%3,%2\n"
208 " xor %0,%3,%0\n"
209 " stl_c %0,%1\n"
210 " beq %0,3f\n"
211 #ifdef CONFIG_SMP
212 " mb\n"
213 #endif
214 ".subsection 2\n"
215 "3: br 1b\n"
216 ".previous"
217 :"=&r" (temp), "=m" (*m), "=&r" (oldbit)
218 :"Ir" (1UL << (nr & 31)), "m" (*m) : "memory");
219
220 return oldbit != 0;
221 }
222
223 static inline int
test_bit(int nr,volatile void * addr)224 test_bit(int nr, volatile void * addr)
225 {
226 return (1UL & (((const int *) addr)[nr >> 5] >> (nr & 31))) != 0UL;
227 }
228
229 /*
230 * ffz = Find First Zero in word. Undefined if no zero exists,
231 * so code should check against ~0UL first..
232 *
233 * Do a binary search on the bits. Due to the nature of large
234 * constants on the alpha, it is worthwhile to split the search.
235 */
ffz_b(unsigned long x)236 static inline unsigned long ffz_b(unsigned long x)
237 {
238 unsigned long sum = 0;
239
240 x = ~x & -~x; /* set first 0 bit, clear others */
241 if (x & 0xF0) sum += 4;
242 if (x & 0xCC) sum += 2;
243 if (x & 0xAA) sum += 1;
244
245 return sum;
246 }
247
ffz(unsigned long word)248 static inline unsigned long ffz(unsigned long word)
249 {
250 #if defined(__alpha_cix__) && defined(__alpha_fix__)
251 /* Whee. EV67 can calculate it directly. */
252 unsigned long result;
253 __asm__("cttz %1,%0" : "=r"(result) : "r"(~word));
254 return result;
255 #else
256 unsigned long bits, qofs, bofs;
257
258 __asm__("cmpbge %1,%2,%0" : "=r"(bits) : "r"(word), "r"(~0UL));
259 qofs = ffz_b(bits);
260 __asm__("extbl %1,%2,%0" : "=r"(bits) : "r"(word), "r"(qofs));
261 bofs = ffz_b(bits);
262
263 return qofs*8 + bofs;
264 #endif
265 }
266
267 #ifdef __KERNEL__
268
269 /*
270 * ffs: find first bit set. This is defined the same way as
271 * the libc and compiler builtin ffs routines, therefore
272 * differs in spirit from the above ffz (man ffs).
273 */
274
ffs(int word)275 static inline int ffs(int word)
276 {
277 int result = ffz(~word);
278 return word ? result+1 : 0;
279 }
280
281 /* Compute powers of two for the given integer. */
floor_log2(unsigned long word)282 static inline int floor_log2(unsigned long word)
283 {
284 long bit;
285 #if defined(__alpha_cix__) && defined(__alpha_fix__)
286 __asm__("ctlz %1,%0" : "=r"(bit) : "r"(word));
287 return 63 - bit;
288 #else
289 for (bit = -1; word ; bit++)
290 word >>= 1;
291 return bit;
292 #endif
293 }
294
ceil_log2(unsigned int word)295 static inline int ceil_log2(unsigned int word)
296 {
297 long bit = floor_log2(word);
298 return bit + (word > (1UL << bit));
299 }
300
301 /*
302 * hweightN: returns the hamming weight (i.e. the number
303 * of bits set) of a N-bit word
304 */
305
306 #if defined(__alpha_cix__) && defined(__alpha_fix__)
307 /* Whee. EV67 can calculate it directly. */
hweight64(unsigned long w)308 static inline unsigned long hweight64(unsigned long w)
309 {
310 unsigned long result;
311 __asm__("ctpop %1,%0" : "=r"(result) : "r"(w));
312 return result;
313 }
314
315 #define hweight32(x) hweight64((x) & 0xfffffffful)
316 #define hweight16(x) hweight64((x) & 0xfffful)
317 #define hweight8(x) hweight64((x) & 0xfful)
318 #else
319 #define hweight32(x) generic_hweight32(x)
320 #define hweight16(x) generic_hweight16(x)
321 #define hweight8(x) generic_hweight8(x)
322 #endif
323
324 #endif /* __KERNEL__ */
325
326 /*
327 * Find next zero bit in a bitmap reasonably efficiently..
328 */
329 static inline unsigned long
find_next_zero_bit(void * addr,unsigned long size,unsigned long offset)330 find_next_zero_bit(void * addr, unsigned long size, unsigned long offset)
331 {
332 unsigned long * p = ((unsigned long *) addr) + (offset >> 6);
333 unsigned long result = offset & ~63UL;
334 unsigned long tmp;
335
336 if (offset >= size)
337 return size;
338 size -= result;
339 offset &= 63UL;
340 if (offset) {
341 tmp = *(p++);
342 tmp |= ~0UL >> (64-offset);
343 if (size < 64)
344 goto found_first;
345 if (~tmp)
346 goto found_middle;
347 size -= 64;
348 result += 64;
349 }
350 while (size & ~63UL) {
351 if (~(tmp = *(p++)))
352 goto found_middle;
353 result += 64;
354 size -= 64;
355 }
356 if (!size)
357 return result;
358 tmp = *p;
359 found_first:
360 tmp |= ~0UL << size;
361 if (tmp == ~0UL) /* Are any bits zero? */
362 return result + size; /* Nope. */
363 found_middle:
364 return result + ffz(tmp);
365 }
366
367 /*
368 * The optimizer actually does good code for this case..
369 */
370 #define find_first_zero_bit(addr, size) \
371 find_next_zero_bit((addr), (size), 0)
372
373 #ifdef __KERNEL__
374
375 #define ext2_set_bit __test_and_set_bit
376 #define ext2_clear_bit __test_and_clear_bit
377 #define ext2_test_bit test_bit
378 #define ext2_find_first_zero_bit find_first_zero_bit
379 #define ext2_find_next_zero_bit find_next_zero_bit
380
381 /* Bitmap functions for the minix filesystem. */
382 #define minix_test_and_set_bit(nr,addr) __test_and_set_bit(nr,addr)
383 #define minix_set_bit(nr,addr) __set_bit(nr,addr)
384 #define minix_test_and_clear_bit(nr,addr) __test_and_clear_bit(nr,addr)
385 #define minix_test_bit(nr,addr) test_bit(nr,addr)
386 #define minix_find_first_zero_bit(addr,size) find_first_zero_bit(addr,size)
387
388 #endif /* __KERNEL__ */
389
390 #endif /* _ALPHA_BITOPS_H */
391