1 #ifndef _ALPHA_BITOPS_H
2 #define _ALPHA_BITOPS_H
4 #include <linux/config.h>
5 #include <linux/kernel.h>
8 * Copyright 1994, Linus Torvalds.
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.
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.
20 * bit 0 is the LSB of addr; bit 64 is the LSB of (addr+1).
24 set_bit(unsigned long nr, volatile void * addr)
27 int *m = ((int *) addr) + (nr >> 5);
37 :"=&r" (temp), "=m" (*m)
38 :"Ir" (1UL << (nr & 31)), "m" (*m));
42 * WARNING: non atomic version.
45 __set_bit(unsigned long nr, volatile void * addr)
47 int *m = ((int *) addr) + (nr >> 5);
52 #define smp_mb__before_clear_bit() smp_mb()
53 #define smp_mb__after_clear_bit() smp_mb()
56 clear_bit(unsigned long nr, volatile void * addr)
59 int *m = ((int *) addr) + (nr >> 5);
69 :"=&r" (temp), "=m" (*m)
70 :"Ir" (~(1UL << (nr & 31))), "m" (*m));
74 * WARNING: non atomic version.
76 static __inline__ void
77 __change_bit(unsigned long nr, volatile void * addr)
79 int *m = ((int *) addr) + (nr >> 5);
85 change_bit(unsigned long nr, volatile void * addr)
88 int *m = ((int *) addr) + (nr >> 5);
98 :"=&r" (temp), "=m" (*m)
99 :"Ir" (1UL << (nr & 31)), "m" (*m));
103 test_and_set_bit(unsigned long nr, volatile void *addr)
105 unsigned long oldbit;
107 int *m = ((int *) addr) + (nr >> 5);
109 __asm__ __volatile__(
123 :"=&r" (temp), "=m" (*m), "=&r" (oldbit)
124 :"Ir" (1UL << (nr & 31)), "m" (*m) : "memory");
130 * WARNING: non atomic version.
133 __test_and_set_bit(unsigned long nr, volatile void * addr)
135 unsigned long mask = 1 << (nr & 0x1f);
136 int *m = ((int *) addr) + (nr >> 5);
140 return (old & mask) != 0;
144 test_and_clear_bit(unsigned long nr, volatile void * addr)
146 unsigned long oldbit;
148 int *m = ((int *) addr) + (nr >> 5);
150 __asm__ __volatile__(
164 :"=&r" (temp), "=m" (*m), "=&r" (oldbit)
165 :"Ir" (1UL << (nr & 31)), "m" (*m) : "memory");
171 * WARNING: non atomic version.
174 __test_and_clear_bit(unsigned long nr, volatile void * addr)
176 unsigned long mask = 1 << (nr & 0x1f);
177 int *m = ((int *) addr) + (nr >> 5);
181 return (old & mask) != 0;
185 * WARNING: non atomic version.
187 static __inline__ int
188 __test_and_change_bit(unsigned long nr, volatile void * addr)
190 unsigned long mask = 1 << (nr & 0x1f);
191 int *m = ((int *) addr) + (nr >> 5);
195 return (old & mask) != 0;
199 test_and_change_bit(unsigned long nr, volatile void * addr)
201 unsigned long oldbit;
203 int *m = ((int *) addr) + (nr >> 5);
205 __asm__ __volatile__(
217 :"=&r" (temp), "=m" (*m), "=&r" (oldbit)
218 :"Ir" (1UL << (nr & 31)), "m" (*m) : "memory");
224 test_bit(int nr, volatile void * addr)
226 return (1UL & (((const int *) addr)[nr >> 5] >> (nr & 31))) != 0UL;
230 * ffz = Find First Zero in word. Undefined if no zero exists,
231 * so code should check against ~0UL first..
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.
236 static inline unsigned long ffz_b(unsigned long x)
238 unsigned long sum = 0;
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;
248 static inline unsigned long ffz(unsigned long word)
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));
256 unsigned long bits, qofs, bofs;
258 __asm__("cmpbge %1,%2,%0" : "=r"(bits) : "r"(word), "r"(~0UL));
260 __asm__("extbl %1,%2,%0" : "=r"(bits) : "r"(word), "r"(qofs));
263 return qofs*8 + bofs;
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).
275 static inline int ffs(int word)
277 int result = ffz(~word);
278 return word ? result+1 : 0;
281 /* Compute powers of two for the given integer. */
282 static inline int floor_log2(unsigned long word)
285 #if defined(__alpha_cix__) && defined(__alpha_fix__)
286 __asm__("ctlz %1,%0" : "=r"(bit) : "r"(word));
289 for (bit = -1; word ; bit++)
295 static inline int ceil_log2(unsigned int word)
297 long bit = floor_log2(word);
298 return bit + (word > (1UL << bit));
302 * hweightN: returns the hamming weight (i.e. the number
303 * of bits set) of a N-bit word
306 #if defined(__alpha_cix__) && defined(__alpha_fix__)
307 /* Whee. EV67 can calculate it directly. */
308 static inline unsigned long hweight64(unsigned long w)
310 unsigned long result;
311 __asm__("ctpop %1,%0" : "=r"(result) : "r"(w));
315 #define hweight32(x) hweight64((x) & 0xfffffffful)
316 #define hweight16(x) hweight64((x) & 0xfffful)
317 #define hweight8(x) hweight64((x) & 0xfful)
319 #define hweight32(x) generic_hweight32(x)
320 #define hweight16(x) generic_hweight16(x)
321 #define hweight8(x) generic_hweight8(x)
324 #endif /* __KERNEL__ */
327 * Find next zero bit in a bitmap reasonably efficiently..
329 static inline unsigned long
330 find_next_zero_bit(void * addr, unsigned long size, unsigned long offset)
332 unsigned long * p = ((unsigned long *) addr) + (offset >> 6);
333 unsigned long result = offset & ~63UL;
342 tmp |= ~0UL >> (64-offset);
350 while (size & ~63UL) {
361 if (tmp == ~0UL) /* Are any bits zero? */
362 return result + size; /* Nope. */
364 return result + ffz(tmp);
368 * The optimizer actually does good code for this case..
370 #define find_first_zero_bit(addr, size) \
371 find_next_zero_bit((addr), (size), 0)
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
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)
388 #endif /* __KERNEL__ */
390 #endif /* _ALPHA_BITOPS_H */