LXR linux/arch/parisc/lib/bitops.c

   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