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...........192|
19 * |31.....0|63....32|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>
49 /* PPC bit number conversion */
50 #define PPC_BITLSHIFT(be) (BITS_PER_LONG - 1 - (be))
51 #define PPC_BIT(bit) (1UL << PPC_BITLSHIFT(bit))
52 #define PPC_BITMASK(bs, be) ((PPC_BIT(bs) - PPC_BIT(be)) | PPC_BIT(bs))
54 /* Put a PPC bit into a "normal" bit position */
55 #define PPC_BITEXTRACT(bits, ppc_bit, dst_bit) \
56 ((((bits) >> PPC_BITLSHIFT(ppc_bit)) & 1) << (dst_bit))
58 #include <asm/barrier.h>
60 /* Macro for generating the ***_bits() functions */
61 #define DEFINE_BITOP(fn, op, prefix) \
62 static __inline__ void fn(unsigned long mask, \
63 volatile unsigned long *_p) \
66 unsigned long *p = (unsigned long *)_p; \
67 __asm__ __volatile__ ( \
69 "1:" PPC_LLARX(%0,0,%3,0) "\n" \
70 stringify_in_c(op) "%0,%0,%2\n" \
72 PPC_STLCX "%0,0,%3\n" \
74 : "=&r" (old), "+m" (*p) \
75 : "r" (mask), "r" (p) \
79 DEFINE_BITOP(set_bits, or, "")
80 DEFINE_BITOP(clear_bits, andc, "")
81 DEFINE_BITOP(clear_bits_unlock, andc, PPC_RELEASE_BARRIER)
82 DEFINE_BITOP(change_bits, xor, "")
84 static __inline__ void set_bit(int nr, volatile unsigned long *addr)
86 set_bits(BIT_MASK(nr), addr + BIT_WORD(nr));
89 static __inline__ void clear_bit(int nr, volatile unsigned long *addr)
91 clear_bits(BIT_MASK(nr), addr + BIT_WORD(nr));
94 static __inline__ void clear_bit_unlock(int nr, volatile unsigned long *addr)
96 clear_bits_unlock(BIT_MASK(nr), addr + BIT_WORD(nr));
99 static __inline__ void change_bit(int nr, volatile unsigned long *addr)
101 change_bits(BIT_MASK(nr), addr + BIT_WORD(nr));
104 /* Like DEFINE_BITOP(), with changes to the arguments to 'op' and the output
106 #define DEFINE_TESTOP(fn, op, prefix, postfix, eh) \
107 static __inline__ unsigned long fn( \
108 unsigned long mask, \
109 volatile unsigned long *_p) \
111 unsigned long old, t; \
112 unsigned long *p = (unsigned long *)_p; \
113 __asm__ __volatile__ ( \
115 "1:" PPC_LLARX(%0,0,%3,eh) "\n" \
116 stringify_in_c(op) "%1,%0,%2\n" \
118 PPC_STLCX "%1,0,%3\n" \
121 : "=&r" (old), "=&r" (t) \
122 : "r" (mask), "r" (p) \
124 return (old & mask); \
127 DEFINE_TESTOP(test_and_set_bits, or, PPC_ATOMIC_ENTRY_BARRIER,
128 PPC_ATOMIC_EXIT_BARRIER, 0)
129 DEFINE_TESTOP(test_and_set_bits_lock, or, "",
130 PPC_ACQUIRE_BARRIER, 1)
131 DEFINE_TESTOP(test_and_clear_bits, andc, PPC_ATOMIC_ENTRY_BARRIER,
132 PPC_ATOMIC_EXIT_BARRIER, 0)
133 DEFINE_TESTOP(test_and_change_bits, xor, PPC_ATOMIC_ENTRY_BARRIER,
134 PPC_ATOMIC_EXIT_BARRIER, 0)
136 static __inline__ int test_and_set_bit(unsigned long nr,
137 volatile unsigned long *addr)
139 return test_and_set_bits(BIT_MASK(nr), addr + BIT_WORD(nr)) != 0;
142 static __inline__ int test_and_set_bit_lock(unsigned long nr,
143 volatile unsigned long *addr)
145 return test_and_set_bits_lock(BIT_MASK(nr),
146 addr + BIT_WORD(nr)) != 0;
149 static __inline__ int test_and_clear_bit(unsigned long nr,
150 volatile unsigned long *addr)
152 return test_and_clear_bits(BIT_MASK(nr), addr + BIT_WORD(nr)) != 0;
155 static __inline__ int test_and_change_bit(unsigned long nr,
156 volatile unsigned long *addr)
158 return test_and_change_bits(BIT_MASK(nr), addr + BIT_WORD(nr)) != 0;
162 static __inline__ unsigned long clear_bit_unlock_return_word(int nr,
163 volatile unsigned long *addr)
165 unsigned long old, t;
166 unsigned long *p = (unsigned long *)addr + BIT_WORD(nr);
167 unsigned long mask = BIT_MASK(nr);
169 __asm__ __volatile__ (
171 "1:" PPC_LLARX(%0,0,%3,0) "\n"
174 PPC_STLCX "%1,0,%3\n"
176 : "=&r" (old), "=&r" (t)
177 : "r" (mask), "r" (p)
183 /* This is a special function for mm/filemap.c */
184 #define clear_bit_unlock_is_negative_byte(nr, addr) \
185 (clear_bit_unlock_return_word(nr, addr) & BIT_MASK(PG_waiters))
187 #endif /* CONFIG_PPC64 */
189 #include <asm-generic/bitops/non-atomic.h>
191 static __inline__ void __clear_bit_unlock(int nr, volatile unsigned long *addr)
193 __asm__ __volatile__(PPC_RELEASE_BARRIER "" ::: "memory");
194 __clear_bit(nr, addr);
198 * Return the zero-based bit position (LE, not IBM bit numbering) of
199 * the most significant 1-bit in a double word.
201 static __inline__ __attribute__((const))
202 int __ilog2(unsigned long x)
206 asm (PPC_CNTLZL "%0,%1" : "=r" (lz) : "r" (x));
207 return BITS_PER_LONG - 1 - lz;
210 static inline __attribute__((const))
211 int __ilog2_u32(u32 n)
214 asm ("cntlzw %0,%1" : "=r" (bit) : "r" (n));
219 static inline __attribute__((const))
220 int __ilog2_u64(u64 n)
223 asm ("cntlzd %0,%1" : "=r" (bit) : "r" (n));
229 * Determines the bit position of the least significant 0 bit in the
230 * specified double word. The returned bit position will be
231 * zero-based, starting from the right side (63/31 - 0).
233 static __inline__ unsigned long ffz(unsigned long x)
235 /* no zero exists anywhere in the 8 byte area. */
237 return BITS_PER_LONG;
240 * Calculate the bit position of the least significant '1' bit in x
241 * (since x has been changed this will actually be the least significant
242 * '0' bit in * the original x). Note: (x & -x) gives us a mask that
243 * is the least significant * (RIGHT-most) 1-bit of the value in x.
245 return __ilog2(x & -x);
248 static __inline__ unsigned long __ffs(unsigned long x)
250 return __ilog2(x & -x);
254 * ffs: find first bit set. This is defined the same way as
255 * the libc and compiler builtin ffs routines, therefore
256 * differs in spirit from the above ffz (man ffs).
258 static __inline__ int ffs(int x)
260 unsigned long i = (unsigned long)x;
261 return __ilog2(i & -i) + 1;
265 * fls: find last (most-significant) bit set.
266 * Note fls(0) = 0, fls(1) = 1, fls(0x80000000) = 32.
268 static __inline__ int fls(unsigned int x)
272 asm ("cntlzw %0,%1" : "=r" (lz) : "r" (x));
276 static __inline__ unsigned long __fls(unsigned long x)
282 * 64-bit can do this using one cntlzd (count leading zeroes doubleword)
283 * instruction; for 32-bit we use the generic version, which does two
287 static __inline__ int fls64(__u64 x)
291 asm ("cntlzd %0,%1" : "=r" (lz) : "r" (x));
295 #include <asm-generic/bitops/fls64.h>
296 #endif /* __powerpc64__ */
299 unsigned int __arch_hweight8(unsigned int w);
300 unsigned int __arch_hweight16(unsigned int w);
301 unsigned int __arch_hweight32(unsigned int w);
302 unsigned long __arch_hweight64(__u64 w);
303 #include <asm-generic/bitops/const_hweight.h>
305 #include <asm-generic/bitops/hweight.h>
308 #include <asm-generic/bitops/find.h>
310 /* Little-endian versions */
311 #include <asm-generic/bitops/le.h>
313 /* Bitmap functions for the ext2 filesystem */
315 #include <asm-generic/bitops/ext2-atomic-setbit.h>
317 #include <asm-generic/bitops/sched.h>
319 #endif /* __KERNEL__ */
321 #endif /* _ASM_POWERPC_BITOPS_H */