1 #ifndef _ARCH_ATOMIC_PPC_H
2 #define _ARCH_ATOMIC_PPC_H
5 * Copyright (c) 1991-1994 by Xerox Corporation. All rights reserved.
6 * Copyright (c) 1996-1999 by Silicon Graphics. All rights reserved.
7 * Copyright (c) 1999-2004 Hewlett-Packard Development Company, L.P.
8 * Copyright (c) 2009 Mathieu Desnoyers
10 * THIS MATERIAL IS PROVIDED AS IS, WITH ABSOLUTELY NO WARRANTY EXPRESSED
11 * OR IMPLIED. ANY USE IS AT YOUR OWN RISK.
13 * Permission is hereby granted to use or copy this program
14 * for any purpose, provided the above notices are retained on all copies.
15 * Permission to modify the code and to distribute modified code is granted,
16 * provided the above notices are retained, and a notice that the code was
17 * modified is included with the above copyright notice.
19 * Code inspired from libatomic_ops-1.2, inherited in part from the
20 * Boehm-Demers-Weiser conservative garbage collector.
24 #define BITS_PER_LONG (__SIZEOF_LONG__ * 8)
27 #define ILLEGAL_INSTR ".long 0xd00d00"
29 #ifndef _INCLUDE_API_H
32 * Using a isync as second barrier for exchange to provide acquire semantic.
33 * According to atomic_ops/sysdeps/gcc/powerpc.h, the documentation is "fairly
34 * explicit that this also has acquire semantics."
35 * Derived from AO_compare_and_swap(), but removed the comparison.
38 static __attribute__((always_inline
))
39 unsigned int atomic_exchange_32(volatile unsigned int *addr
, unsigned int val
)
45 "1:\t" "lwarx %0,0,%1\n" /* load and reserve */
46 "stwcx. %2,0,%1\n" /* else store conditional */
47 "bne- 1b\n" /* retry if lost reservation */
56 #if (BITS_PER_LONG == 64)
58 static __attribute__((always_inline
))
59 unsigned long atomic_exchange_64(volatile unsigned long *addr
,
66 "1:\t" "ldarx %0,0,%1\n" /* load and reserve */
67 "stdcx. %2,0,%1\n" /* else store conditional */
68 "bne- 1b\n" /* retry if lost reservation */
79 static __attribute__((always_inline
))
80 unsigned long _atomic_exchange(volatile void *addr
, unsigned long val
, int len
)
83 case 4: return atomic_exchange_32(addr
, val
);
84 #if (BITS_PER_LONG == 64)
85 case 8: return atomic_exchange_64(addr
, val
);
88 /* generate an illegal instruction. Cannot catch this with linker tricks
89 * when optimizations are disabled. */
90 __asm__
__volatile__(ILLEGAL_INSTR
);
94 #define xchg(addr, v) (__typeof__(*(addr))) _atomic_exchange((addr), (v), \
97 #endif /* #ifndef _INCLUDE_API_H */
99 #endif /* ARCH_ATOMIC_PPC_H */
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