2 * PowerPC atomic bit operations.
4 * Merged version by David Gibson <david@gibson.dropbear.id.au>.
5 * Based on ppc64 versions by: Dave Engebretsen, Todd Inglett, Don
6 * Reed, Pat McCarthy, Peter Bergner, Anton Blanchard. They
7 * originally took it from the ppc32 code.
9 * Within a word, bits are numbered LSB first. Lot's of places make
10 * this assumption by directly testing bits with (val & (1<<nr)).
11 * This can cause confusion for large (> 1 word) bitmaps on a
12 * big-endian system because, unlike little endian, the number of each
13 * bit depends on the word size.
15 * The bitop functions are defined to work on unsigned longs, so for a
16 * ppc64 system the bits end up numbered:
17 * |63..............0|127............64|191...........128|255...........196|
19 * |31.....0|63....31|95....64|127...96|159..128|191..160|223..192|255..224|
21 * There are a few little-endian macros used mostly for filesystem
22 * bitmaps, these work on similar bit arrays layouts, but
24 * |7...0|15...8|23...16|31...24|39...32|47...40|55...48|63...56|
26 * The main difference is that bit 3-5 (64b) or 3-4 (32b) in the bit
27 * number field needs to be reversed compared to the big-endian bit
28 * fields. This can be achieved by XOR with 0x38 (64b) or 0x18 (32b).
30 * This program is free software; you can redistribute it and/or
31 * modify it under the terms of the GNU General Public License
32 * as published by the Free Software Foundation; either version
33 * 2 of the License, or (at your option) any later version.
36 #ifndef _ASM_POWERPC_BITOPS_H
37 #define _ASM_POWERPC_BITOPS_H
41 #ifndef _LINUX_BITOPS_H
42 #error only <linux/bitops.h> can be included directly
45 #include <linux/compiler.h>
46 #include <asm/asm-compat.h>
47 #include <asm/synch.h>
50 * clear_bit doesn't imply a memory barrier
52 #define smp_mb__before_clear_bit() smp_mb()
53 #define smp_mb__after_clear_bit() smp_mb()
55 #define BITOP_MASK(nr) (1UL << ((nr) % BITS_PER_LONG))
56 #define BITOP_WORD(nr) ((nr) / BITS_PER_LONG)
57 #define BITOP_LE_SWIZZLE ((BITS_PER_LONG-1) & ~0x7)
59 static __inline__
void set_bit(int nr
, volatile unsigned long *addr
)
62 unsigned long mask
= BITOP_MASK(nr
);
63 unsigned long *p
= ((unsigned long *)addr
) + BITOP_WORD(nr
);
66 "1:" PPC_LLARX
"%0,0,%3 # set_bit\n"
71 : "=&r" (old
), "+m" (*p
)
76 static __inline__
void clear_bit(int nr
, volatile unsigned long *addr
)
79 unsigned long mask
= BITOP_MASK(nr
);
80 unsigned long *p
= ((unsigned long *)addr
) + BITOP_WORD(nr
);
83 "1:" PPC_LLARX
"%0,0,%3 # clear_bit\n"
88 : "=&r" (old
), "+m" (*p
)
93 static __inline__
void clear_bit_unlock(int nr
, volatile unsigned long *addr
)
96 unsigned long mask
= BITOP_MASK(nr
);
97 unsigned long *p
= ((unsigned long *)addr
) + BITOP_WORD(nr
);
101 "1:" PPC_LLARX
"%0,0,%3 # clear_bit_unlock\n"
104 PPC_STLCX
"%0,0,%3\n"
106 : "=&r" (old
), "+m" (*p
)
107 : "r" (mask
), "r" (p
)
111 static __inline__
void change_bit(int nr
, volatile unsigned long *addr
)
114 unsigned long mask
= BITOP_MASK(nr
);
115 unsigned long *p
= ((unsigned long *)addr
) + BITOP_WORD(nr
);
117 __asm__
__volatile__(
118 "1:" PPC_LLARX
"%0,0,%3 # change_bit\n"
121 PPC_STLCX
"%0,0,%3\n"
123 : "=&r" (old
), "+m" (*p
)
124 : "r" (mask
), "r" (p
)
128 static __inline__
int test_and_set_bit(unsigned long nr
,
129 volatile unsigned long *addr
)
131 unsigned long old
, t
;
132 unsigned long mask
= BITOP_MASK(nr
);
133 unsigned long *p
= ((unsigned long *)addr
) + BITOP_WORD(nr
);
135 __asm__
__volatile__(
137 "1:" PPC_LLARX
"%0,0,%3 # test_and_set_bit\n"
140 PPC_STLCX
"%1,0,%3 \n"
143 : "=&r" (old
), "=&r" (t
)
144 : "r" (mask
), "r" (p
)
147 return (old
& mask
) != 0;
150 static __inline__
int test_and_set_bit_lock(unsigned long nr
,
151 volatile unsigned long *addr
)
153 unsigned long old
, t
;
154 unsigned long mask
= BITOP_MASK(nr
);
155 unsigned long *p
= ((unsigned long *)addr
) + BITOP_WORD(nr
);
157 __asm__
__volatile__(
158 "1:" PPC_LLARX
"%0,0,%3 # test_and_set_bit_lock\n"
161 PPC_STLCX
"%1,0,%3 \n"
164 : "=&r" (old
), "=&r" (t
)
165 : "r" (mask
), "r" (p
)
168 return (old
& mask
) != 0;
171 static __inline__
int test_and_clear_bit(unsigned long nr
,
172 volatile unsigned long *addr
)
174 unsigned long old
, t
;
175 unsigned long mask
= BITOP_MASK(nr
);
176 unsigned long *p
= ((unsigned long *)addr
) + BITOP_WORD(nr
);
178 __asm__
__volatile__(
180 "1:" PPC_LLARX
"%0,0,%3 # test_and_clear_bit\n"
183 PPC_STLCX
"%1,0,%3 \n"
186 : "=&r" (old
), "=&r" (t
)
187 : "r" (mask
), "r" (p
)
190 return (old
& mask
) != 0;
193 static __inline__
int test_and_change_bit(unsigned long nr
,
194 volatile unsigned long *addr
)
196 unsigned long old
, t
;
197 unsigned long mask
= BITOP_MASK(nr
);
198 unsigned long *p
= ((unsigned long *)addr
) + BITOP_WORD(nr
);
200 __asm__
__volatile__(
202 "1:" PPC_LLARX
"%0,0,%3 # test_and_change_bit\n"
205 PPC_STLCX
"%1,0,%3 \n"
208 : "=&r" (old
), "=&r" (t
)
209 : "r" (mask
), "r" (p
)
212 return (old
& mask
) != 0;
215 static __inline__
void set_bits(unsigned long mask
, unsigned long *addr
)
219 __asm__
__volatile__(
220 "1:" PPC_LLARX
"%0,0,%3 # set_bits\n"
222 PPC_STLCX
"%0,0,%3\n"
224 : "=&r" (old
), "+m" (*addr
)
225 : "r" (mask
), "r" (addr
)
229 #include <asm-generic/bitops/non-atomic.h>
231 static __inline__
void __clear_bit_unlock(int nr
, volatile unsigned long *addr
)
233 __asm__
__volatile__(LWSYNC_ON_SMP
"" ::: "memory");
234 __clear_bit(nr
, addr
);
238 * Return the zero-based bit position (LE, not IBM bit numbering) of
239 * the most significant 1-bit in a double word.
241 static __inline__
__attribute__((const))
242 int __ilog2(unsigned long x
)
246 asm (PPC_CNTLZL
"%0,%1" : "=r" (lz
) : "r" (x
));
247 return BITS_PER_LONG
- 1 - lz
;
250 static inline __attribute__((const))
251 int __ilog2_u32(u32 n
)
254 asm ("cntlzw %0,%1" : "=r" (bit
) : "r" (n
));
259 static inline __attribute__((const))
260 int __ilog2_u64(u64 n
)
263 asm ("cntlzd %0,%1" : "=r" (bit
) : "r" (n
));
269 * Determines the bit position of the least significant 0 bit in the
270 * specified double word. The returned bit position will be
271 * zero-based, starting from the right side (63/31 - 0).
273 static __inline__
unsigned long ffz(unsigned long x
)
275 /* no zero exists anywhere in the 8 byte area. */
277 return BITS_PER_LONG
;
280 * Calculate the bit position of the least signficant '1' bit in x
281 * (since x has been changed this will actually be the least signficant
282 * '0' bit in * the original x). Note: (x & -x) gives us a mask that
283 * is the least significant * (RIGHT-most) 1-bit of the value in x.
285 return __ilog2(x
& -x
);
288 static __inline__
int __ffs(unsigned long x
)
290 return __ilog2(x
& -x
);
294 * ffs: find first bit set. This is defined the same way as
295 * the libc and compiler builtin ffs routines, therefore
296 * differs in spirit from the above ffz (man ffs).
298 static __inline__
int ffs(int x
)
300 unsigned long i
= (unsigned long)x
;
301 return __ilog2(i
& -i
) + 1;
305 * fls: find last (most-significant) bit set.
306 * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
308 static __inline__
int fls(unsigned int x
)
312 asm ("cntlzw %0,%1" : "=r" (lz
) : "r" (x
));
315 #include <asm-generic/bitops/fls64.h>
317 #include <asm-generic/bitops/hweight.h>
319 #define find_first_zero_bit(addr, size) find_next_zero_bit((addr), (size), 0)
320 unsigned long find_next_zero_bit(const unsigned long *addr
,
321 unsigned long size
, unsigned long offset
);
323 * find_first_bit - find the first set bit in a memory region
324 * @addr: The address to start the search at
325 * @size: The maximum size to search
327 * Returns the bit-number of the first set bit, not the number of the byte
330 #define find_first_bit(addr, size) find_next_bit((addr), (size), 0)
331 unsigned long find_next_bit(const unsigned long *addr
,
332 unsigned long size
, unsigned long offset
);
334 /* Little-endian versions */
336 static __inline__
int test_le_bit(unsigned long nr
,
337 __const__
unsigned long *addr
)
339 __const__
unsigned char *tmp
= (__const__
unsigned char *) addr
;
340 return (tmp
[nr
>> 3] >> (nr
& 7)) & 1;
343 #define __set_le_bit(nr, addr) \
344 __set_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
345 #define __clear_le_bit(nr, addr) \
346 __clear_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
348 #define test_and_set_le_bit(nr, addr) \
349 test_and_set_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
350 #define test_and_clear_le_bit(nr, addr) \
351 test_and_clear_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
353 #define __test_and_set_le_bit(nr, addr) \
354 __test_and_set_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
355 #define __test_and_clear_le_bit(nr, addr) \
356 __test_and_clear_bit((nr) ^ BITOP_LE_SWIZZLE, (addr))
358 #define find_first_zero_le_bit(addr, size) generic_find_next_zero_le_bit((addr), (size), 0)
359 unsigned long generic_find_next_zero_le_bit(const unsigned long *addr
,
360 unsigned long size
, unsigned long offset
);
362 /* Bitmap functions for the ext2 filesystem */
364 #define ext2_set_bit(nr,addr) \
365 __test_and_set_le_bit((nr), (unsigned long*)addr)
366 #define ext2_clear_bit(nr, addr) \
367 __test_and_clear_le_bit((nr), (unsigned long*)addr)
369 #define ext2_set_bit_atomic(lock, nr, addr) \
370 test_and_set_le_bit((nr), (unsigned long*)addr)
371 #define ext2_clear_bit_atomic(lock, nr, addr) \
372 test_and_clear_le_bit((nr), (unsigned long*)addr)
374 #define ext2_test_bit(nr, addr) test_le_bit((nr),(unsigned long*)addr)
376 #define ext2_find_first_zero_bit(addr, size) \
377 find_first_zero_le_bit((unsigned long*)addr, size)
378 #define ext2_find_next_zero_bit(addr, size, off) \
379 generic_find_next_zero_le_bit((unsigned long*)addr, size, off)
381 /* Bitmap functions for the minix filesystem. */
383 #define minix_test_and_set_bit(nr,addr) \
384 __test_and_set_le_bit(nr, (unsigned long *)addr)
385 #define minix_set_bit(nr,addr) \
386 __set_le_bit(nr, (unsigned long *)addr)
387 #define minix_test_and_clear_bit(nr,addr) \
388 __test_and_clear_le_bit(nr, (unsigned long *)addr)
389 #define minix_test_bit(nr,addr) \
390 test_le_bit(nr, (unsigned long *)addr)
392 #define minix_find_first_zero_bit(addr,size) \
393 find_first_zero_le_bit((unsigned long *)addr, size)
395 #include <asm-generic/bitops/sched.h>
397 #endif /* __KERNEL__ */
399 #endif /* _ASM_POWERPC_BITOPS_H */