Linux kernel mirror (for testing)
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linux
1/*
2 * bitops.c: atomic operations which got too long to be inlined all over
3 * the place.
4 *
5 * Copyright 1999 Philipp Rumpf (prumpf@tux.org)
6 * Copyright 2000 Grant Grundler (grundler@cup.hp.com)
7 */
8
9#include <linux/kernel.h>
10#include <linux/spinlock.h>
11#include <linux/atomic.h>
12
13#ifdef CONFIG_SMP
14arch_spinlock_t __atomic_hash[ATOMIC_HASH_SIZE] __lock_aligned = {
15 [0 ... (ATOMIC_HASH_SIZE-1)] = __ARCH_SPIN_LOCK_UNLOCKED
16};
17#endif
18
19#ifdef CONFIG_64BIT
20unsigned long __xchg64(unsigned long x, unsigned long *ptr)
21{
22 unsigned long temp, flags;
23
24 _atomic_spin_lock_irqsave(ptr, flags);
25 temp = *ptr;
26 *ptr = x;
27 _atomic_spin_unlock_irqrestore(ptr, flags);
28 return temp;
29}
30#endif
31
32unsigned long __xchg32(int x, int *ptr)
33{
34 unsigned long flags;
35 long temp;
36
37 _atomic_spin_lock_irqsave(ptr, flags);
38 temp = (long) *ptr; /* XXX - sign extension wanted? */
39 *ptr = x;
40 _atomic_spin_unlock_irqrestore(ptr, flags);
41 return (unsigned long)temp;
42}
43
44
45unsigned long __xchg8(char x, char *ptr)
46{
47 unsigned long flags;
48 long temp;
49
50 _atomic_spin_lock_irqsave(ptr, flags);
51 temp = (long) *ptr; /* XXX - sign extension wanted? */
52 *ptr = x;
53 _atomic_spin_unlock_irqrestore(ptr, flags);
54 return (unsigned long)temp;
55}
56
57
58u64 __cmpxchg_u64(volatile u64 *ptr, u64 old, u64 new)
59{
60 unsigned long flags;
61 u64 prev;
62
63 _atomic_spin_lock_irqsave(ptr, flags);
64 if ((prev = *ptr) == old)
65 *ptr = new;
66 _atomic_spin_unlock_irqrestore(ptr, flags);
67 return prev;
68}
69
70unsigned long __cmpxchg_u32(volatile unsigned int *ptr, unsigned int old, unsigned int new)
71{
72 unsigned long flags;
73 unsigned int prev;
74
75 _atomic_spin_lock_irqsave(ptr, flags);
76 if ((prev = *ptr) == old)
77 *ptr = new;
78 _atomic_spin_unlock_irqrestore(ptr, flags);
79 return (unsigned long)prev;
80}