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/* atomic.c: atomic operations which got too long to be inlined all over
* the place.
*
* Copyright 1999 Philipp Rumpf (prumpf@tux.org */
#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/spinlock.h>
#include <asm/system.h>
#include <asm/atomic.h>
#ifdef CONFIG_SMP
spinlock_t __atomic_hash[ATOMIC_HASH_SIZE] = {
[0 ... (ATOMIC_HASH_SIZE-1)] = SPIN_LOCK_UNLOCKED
};
#endif
spinlock_t __atomic_lock = SPIN_LOCK_UNLOCKED;
#ifndef __LP64__
unsigned long __xchg(unsigned long x, unsigned long *ptr, int size)
{
unsigned long temp, flags;
if (size != sizeof x) {
printk("__xchg called with bad pointer\n");
}
spin_lock_irqsave(&__atomic_lock, flags);
temp = *ptr;
*ptr = x;
spin_unlock_irqrestore(&__atomic_lock, flags);
return temp;
}
#else
unsigned long __xchg(unsigned long x, unsigned long *ptr, int size)
{
unsigned long temp, flags;
unsigned int *ptr32;
if (size == 8) {
try_long:
spin_lock_irqsave(&__atomic_lock, flags);
temp = *ptr;
*ptr = x;
spin_unlock_irqrestore(&__atomic_lock, flags);
return temp;
}
if (size == 4) {
ptr32 = (unsigned int *)ptr;
spin_lock_irqsave(&__atomic_lock, flags);
temp = (unsigned long)*ptr32;
*ptr32 = (unsigned int)x;
spin_unlock_irqrestore(&__atomic_lock, flags);
return temp;
}
printk("__xchg called with bad pointer\n");
goto try_long;
}
#endif
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