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/config.h>
10#include <linux/kernel.h>
11#include <linux/spinlock.h>
12#include <asm/system.h>
13#include <asm/atomic.h>
14
15#ifdef CONFIG_SMP
16spinlock_t __atomic_hash[ATOMIC_HASH_SIZE] __lock_aligned = {
17 [0 ... (ATOMIC_HASH_SIZE-1)] = SPIN_LOCK_UNLOCKED
18};
19#endif
20
21#ifdef __LP64__
22unsigned long __xchg64(unsigned long x, unsigned long *ptr)
23{
24 unsigned long temp, flags;
25
26 _atomic_spin_lock_irqsave(ptr, flags);
27 temp = *ptr;
28 *ptr = x;
29 _atomic_spin_unlock_irqrestore(ptr, flags);
30 return temp;
31}
32#endif
33
34unsigned long __xchg32(int x, int *ptr)
35{
36 unsigned long flags;
37 long temp;
38
39 _atomic_spin_lock_irqsave(ptr, flags);
40 temp = (long) *ptr; /* XXX - sign extension wanted? */
41 *ptr = x;
42 _atomic_spin_unlock_irqrestore(ptr, flags);
43 return (unsigned long)temp;
44}
45
46
47unsigned long __xchg8(char x, char *ptr)
48{
49 unsigned long flags;
50 long temp;
51
52 _atomic_spin_lock_irqsave(ptr, flags);
53 temp = (long) *ptr; /* XXX - sign extension wanted? */
54 *ptr = x;
55 _atomic_spin_unlock_irqrestore(ptr, flags);
56 return (unsigned long)temp;
57}
58
59
60#ifdef __LP64__
61unsigned long __cmpxchg_u64(volatile unsigned long *ptr, unsigned long old, unsigned long new)
62{
63 unsigned long flags;
64 unsigned long prev;
65
66 _atomic_spin_lock_irqsave(ptr, flags);
67 if ((prev = *ptr) == old)
68 *ptr = new;
69 _atomic_spin_unlock_irqrestore(ptr, flags);
70 return prev;
71}
72#endif
73
74unsigned long __cmpxchg_u32(volatile unsigned int *ptr, unsigned int old, unsigned int new)
75{
76 unsigned long flags;
77 unsigned int prev;
78
79 _atomic_spin_lock_irqsave(ptr, flags);
80 if ((prev = *ptr) == old)
81 *ptr = new;
82 _atomic_spin_unlock_irqrestore(ptr, flags);
83 return (unsigned long)prev;
84}