atomic.h

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/*
 * Copyright (c) 2001-2004 Jakub Jermar
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#ifndef LIBC_ia32_ATOMIC_H_
#define LIBC_ia32_ATOMIC_H_

#define LIBC_ARCH_ATOMIC_H_

#include <atomicdflt.h>

static inline void atomic_inc(atomic_t *val)
{
        asm volatile (
                "lock incl %[count]\n"
                : [count] "+m" (val->count)
        );
}

static inline void atomic_dec(atomic_t *val)
{
        asm volatile (
                "lock decl %[count]\n"
                : [count] "+m" (val->count)
        );
}

static inline atomic_count_t atomic_postinc(atomic_t *val)
{
        atomic_count_t r = 1;
        
        asm volatile (
                "lock xaddl %[r], %[count]\n"
                : [count] "+m" (val->count),
                  [r] "+r" (r)
        );
        
        return r;
}

static inline atomic_count_t atomic_postdec(atomic_t *val)
{
        atomic_count_t r = -1;
        
        asm volatile (
                "lock xaddl %[r], %[count]\n"
                : [count] "+m" (val->count),
                  [r] "+r" (r)
        );
        
        return r;
}

#define atomic_preinc(val)  (atomic_postinc(val) + 1)
#define atomic_predec(val)  (atomic_postdec(val) - 1)

#endif

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