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 extern __inline__ void
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 extern __inline__ void
45 __set_bit(unsigned long nr, volatile void * addr)
46 {
47 int *m = ((int *) addr) + (nr >> 5);
48
49 *m |= 1UL << (nr & 31);
50 }
51
52 #define smp_mb__before_clear_bit() smp_mb()
53 #define smp_mb__after_clear_bit() smp_mb()
54
55 extern __inline__ void
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 extern __inline__ void
74 change_bit(unsigned long nr, volatile void * addr)
75 {
76 unsigned long temp;
77 int *m = ((int *) addr) + (nr >> 5);
78
79 __asm__ __volatile__(
80 "1: ldl_l %0,%3\n"
81 " xor %0,%2,%0\n"
82 " stl_c %0,%1\n"
83 " beq %0,2f\n"
84 ".subsection 2\n"
85 "2: br 1b\n"
86 ".previous"
87 :"=&r" (temp), "=m" (*m)
88 :"Ir" (1UL << (nr & 31)), "m" (*m));
89 }
90
91 extern __inline__ int
92 test_and_set_bit(unsigned long nr, volatile void *addr)
93 {
94 unsigned long oldbit;
95 unsigned long temp;
96 int *m = ((int *) addr) + (nr >> 5);
97
98 __asm__ __volatile__(
99 "1: ldl_l %0,%4\n"
100 " and %0,%3,%2\n"
101 " bne %2,2f\n"
102 " xor %0,%3,%0\n"
103 " stl_c %0,%1\n"
104 " beq %0,3f\n"
105 "2:\n"
106 #ifdef CONFIG_SMP
107 " mb\n"
108 #endif
109 ".subsection 2\n"
110 "3: br 1b\n"
111 ".previous"
112 :"=&r" (temp), "=m" (*m), "=&r" (oldbit)
113 :"Ir" (1UL << (nr & 31)), "m" (*m) : "memory");
114
115 return oldbit != 0;
116 }
117
118 /*
119 * WARNING: non atomic version.
120 */
121 extern __inline__ int
122 __test_and_set_bit(unsigned long nr, volatile void * addr)
123 {
124 unsigned long mask = 1 << (nr & 0x1f);
125 int *m = ((int *) addr) + (nr >> 5);
126 int old = *m;
127
128 *m = old | mask;
129 return (old & mask) != 0;
130 }
131
132 extern __inline__ int
133 test_and_clear_bit(unsigned long nr, volatile void * addr)
134 {
135 unsigned long oldbit;
136 unsigned long temp;
137 int *m = ((int *) addr) + (nr >> 5);
138
139 __asm__ __volatile__(
140 "1: ldl_l %0,%4\n"
141 " and %0,%3,%2\n"
142 " beq %2,2f\n"
143 " xor %0,%3,%0\n"
144 " stl_c %0,%1\n"
145 " beq %0,3f\n"
146 "2:\n"
147 #ifdef CONFIG_SMP
148 " mb\n"
149 #endif
150 ".subsection 2\n"
151 "3: br 1b\n"
152 ".previous"
153 :"=&r" (temp), "=m" (*m), "=&r" (oldbit)
154 :"Ir" (1UL << (nr & 31)), "m" (*m) : "memory");
155
156 return oldbit != 0;
157 }
158
159 /*
160 * WARNING: non atomic version.
161 */
162 extern __inline__ int
163 __test_and_clear_bit(unsigned long nr, volatile void * addr)
164 {
165 unsigned long mask = 1 << (nr & 0x1f);
166 int *m = ((int *) addr) + (nr >> 5);
167 int old = *m;
168
169 *m = old & ~mask;
170 return (old & mask) != 0;
171 }
172
173 extern __inline__ int
174 test_and_change_bit(unsigned long nr, volatile void * addr)
175 {
176 unsigned long oldbit;
177 unsigned long temp;
178 int *m = ((int *) addr) + (nr >> 5);
179
180 __asm__ __volatile__(
181 "1: ldl_l %0,%4\n"
182 " and %0,%3,%2\n"
183 " xor %0,%3,%0\n"
184 " stl_c %0,%1\n"
185 " beq %0,3f\n"
186 #ifdef CONFIG_SMP
187 " mb\n"
188 #endif
189 ".subsection 2\n"
190 "3: br 1b\n"
191 ".previous"
192 :"=&r" (temp), "=m" (*m), "=&r" (oldbit)
193 :"Ir" (1UL << (nr & 31)), "m" (*m) : "memory");
194
195 return oldbit != 0;
196 }
197
198 extern __inline__ int
199 test_bit(int nr, volatile void * addr)
200 {
201 return (1UL & (((const int *) addr)[nr >> 5] >> (nr & 31))) != 0UL;
202 }
203
204 /*
205 * ffz = Find First Zero in word. Undefined if no zero exists,
206 * so code should check against ~0UL first..
207 *
208 * Do a binary search on the bits. Due to the nature of large
209 * constants on the alpha, it is worthwhile to split the search.
210 */
211 extern inline unsigned long ffz_b(unsigned long x)
212 {
213 unsigned long sum = 0;
214
215 x = ~x & -~x; /* set first 0 bit, clear others */
216 if (x & 0xF0) sum += 4;
217 if (x & 0xCC) sum += 2;
218 if (x & 0xAA) sum += 1;
219
220 return sum;
221 }
222
223 extern inline unsigned long ffz(unsigned long word)
224 {
225 #if defined(__alpha_cix__) && defined(__alpha_fix__)
226 /* Whee. EV67 can calculate it directly. */
227 unsigned long result;
228 __asm__("cttz %1,%0" : "=r"(result) : "r"(~word));
229 return result;
230 #else
231 unsigned long bits, qofs, bofs;
232
233 __asm__("cmpbge %1,%2,%0" : "=r"(bits) : "r"(word), "r"(~0UL));
234 qofs = ffz_b(bits);
235 __asm__("extbl %1,%2,%0" : "=r"(bits) : "r"(word), "r"(qofs));
236 bofs = ffz_b(bits);
237
238 return qofs*8 + bofs;
239 #endif
240 }
241
242 #ifdef __KERNEL__
243
244 /*
245 * ffs: find first bit set. This is defined the same way as
246 * the libc and compiler builtin ffs routines, therefore
247 * differs in spirit from the above ffz (man ffs).
248 */
249
250 extern inline int ffs(int word)
251 {
252 int result = ffz(~word);
253 return word ? result+1 : 0;
254 }
255
256 /*
257 * hweightN: returns the hamming weight (i.e. the number
258 * of bits set) of a N-bit word
259 */
260
261 #if defined(__alpha_cix__) && defined(__alpha_fix__)
262 /* Whee. EV67 can calculate it directly. */
263 extern __inline__ unsigned long hweight64(unsigned long w)
264 {
265 unsigned long result;
266 __asm__("ctpop %1,%0" : "=r"(result) : "r"(w));
267 return result;
268 }
269
270 #define hweight32(x) hweight64((x) & 0xfffffffful)
271 #define hweight16(x) hweight64((x) & 0xfffful)
272 #define hweight8(x) hweight64((x) & 0xfful)
273 #else
274 #define hweight32(x) generic_hweight32(x)
275 #define hweight16(x) generic_hweight16(x)
276 #define hweight8(x) generic_hweight8(x)
277 #endif
278
279 #endif /* __KERNEL__ */
280
281 /*
282 * Find next zero bit in a bitmap reasonably efficiently..
283 */
284 extern inline unsigned long
285 find_next_zero_bit(void * addr, unsigned long size, unsigned long offset)
286 {
287 unsigned long * p = ((unsigned long *) addr) + (offset >> 6);
288 unsigned long result = offset & ~63UL;
289 unsigned long tmp;
290
291 if (offset >= size)
292 return size;
293 size -= result;
294 offset &= 63UL;
295 if (offset) {
296 tmp = *(p++);
297 tmp |= ~0UL >> (64-offset);
298 if (size < 64)
299 goto found_first;
300 if (~tmp)
301 goto found_middle;
302 size -= 64;
303 result += 64;
304 }
305 while (size & ~63UL) {
306 if (~(tmp = *(p++)))
307 goto found_middle;
308 result += 64;
309 size -= 64;
310 }
311 if (!size)
312 return result;
313 tmp = *p;
314 found_first:
315 tmp |= ~0UL << size;
316 if (tmp == ~0UL) /* Are any bits zero? */
317 return result + size; /* Nope. */
318 found_middle:
319 return result + ffz(tmp);
320 }
321
322 /*
323 * The optimizer actually does good code for this case..
324 */
325 #define find_first_zero_bit(addr, size) \
326 find_next_zero_bit((addr), (size), 0)
327
328 #ifdef __KERNEL__
329
330 #define ext2_set_bit __test_and_set_bit
331 #define ext2_clear_bit __test_and_clear_bit
332 #define ext2_test_bit test_bit
333 #define ext2_find_first_zero_bit find_first_zero_bit
334 #define ext2_find_next_zero_bit find_next_zero_bit
335
336 /* Bitmap functions for the minix filesystem. */
337 #define minix_test_and_set_bit(nr,addr) __test_and_set_bit(nr,addr)
338 #define minix_set_bit(nr,addr) __set_bit(nr,addr)
339 #define minix_test_and_clear_bit(nr,addr) __test_and_clear_bit(nr,addr)
340 #define minix_test_bit(nr,addr) test_bit(nr,addr)
341 #define minix_find_first_zero_bit(addr,size) find_first_zero_bit(addr,size)
342
343 #endif /* __KERNEL__ */
344
345 #endif /* _ALPHA_BITOPS_H */
346
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