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
58#ifdef CONFIG_64BIT
59unsigned long __cmpxchg_u64(volatile unsigned long *ptr, unsigned long old, unsigned long new)
60{
61	unsigned long flags;
62	unsigned long prev;
63
64	_atomic_spin_lock_irqsave(ptr, flags);
65	if ((prev = *ptr) == old)
66		*ptr = new;
67	_atomic_spin_unlock_irqrestore(ptr, flags);
68	return prev;
69}
70#endif
71
72unsigned long __cmpxchg_u32(volatile unsigned int *ptr, unsigned int old, unsigned int new)
73{
74	unsigned long flags;
75	unsigned int prev;
76
77	_atomic_spin_lock_irqsave(ptr, flags);
78	if ((prev = *ptr) == old)
79		*ptr = new;
80	_atomic_spin_unlock_irqrestore(ptr, flags);
81	return (unsigned long)prev;
82}
83