base/include/asm/rtai_atomic.h

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/*
 * Copyright (C) 2003 Philippe Gerum <rpm@xenomai.org>.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#ifndef _RTAI_ASM_I386_ATOMIC_H
#define _RTAI_ASM_I386_ATOMIC_H

#ifdef __KERNEL__

#include <linux/bitops.h>
#include <asm/atomic.h>
#include <asm/system.h>

#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,11)

#define atomic_cmpxchg(v, old, new)  ((int)cmpxchg(&((v)->counter), old, new))
#define atomic_xchg(v, new)          (xchg(&((v)->counter), new))

#endif

#else /* !__KERNEL__ */

#ifndef likely
#if __GNUC__ == 2 && __GNUC_MINOR__ < 96
#define __builtin_expect(x, expected_value) (x)
#endif
#define likely(x)   __builtin_expect(!!(x), 1)
#define unlikely(x) __builtin_expect(!!(x), 0)
#endif /* !likely */

#ifdef CONFIG_SMP
#define LOCK_PREFIX "lock ; "
#else
#define LOCK_PREFIX ""
#endif

#define atomic_t int

struct __rtai_xchg_dummy { unsigned long a[100]; };
#define __rtai_xg(x) ((struct __rtai_xchg_dummy *)(x))

static inline unsigned long atomic_xchg(volatile void *ptr, unsigned long x)
{
    __asm__ __volatile__(LOCK_PREFIX "xchgl %0,%1"
                     :"=r" (x)
                 :"m" (*__rtai_xg(ptr)), "0" (x)
                 :"memory");
    return x;
}

static inline unsigned long atomic_cmpxchg(volatile void *ptr, unsigned long o, unsigned long n)
{
    unsigned long prev;
    __asm__ __volatile__(LOCK_PREFIX "cmpxchgl %1,%2"
                 : "=a"(prev)
                 : "q"(n), "m" (*__rtai_xg(ptr)), "0" (o)
                 : "memory");
    return prev;
}

static __inline__ int atomic_dec_and_test(atomic_t *v)
{
        unsigned char c;

        __asm__ __volatile__(
                LOCK_PREFIX "decl %0; sete %1"
                :"=m" (*__rtai_xg(v)), "=qm" (c)
                :"m" (*__rtai_xg(v)) : "memory");
        return c != 0;
}

static __inline__ void atomic_inc(atomic_t *v)
{
        __asm__ __volatile__(
                LOCK_PREFIX "incl %0"
                :"=m" (*__rtai_xg(v))
                :"m" (*__rtai_xg(v)));
}

/* Depollute the namespace a bit. */
#undef ADDR

#endif /* __KERNEL__ */

#endif /* !_RTAI_ASM_I386_ATOMIC_H */

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