source: mainline/kernel/arch/ia64/include/atomic.h@ 9035c5a

/*
 * Copyright (c) 2005 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.
 */

/** @addtogroup ia64    
 * @{
 */
/** @file
 */

#ifndef KERN_ia64_ATOMIC_H_
#define KERN_ia64_ATOMIC_H_

/** Atomic addition.
 *
 * @param val           Atomic value.
 * @param imm           Value to add.
 *
 * @return              Value before addition.
 */
static inline long atomic_add(atomic_t *val, int imm)
{
        long v;

        asm volatile ("fetchadd8.rel %0 = %1, %2\n" : "=r" (v),
            "+m" (val->count) : "i" (imm));
 
        return v;
}

static inline uint64_t test_and_set(atomic_t *val)
{
        uint64_t v;
                
        asm volatile (
                "movl %0 = 0x1;;\n"
                "xchg8 %0 = %1, %0;;\n"
                : "=r" (v), "+m" (val->count)
        );
        
        return v;
}

static inline void atomic_lock_arch(atomic_t *val)
{
        do {
                while (val->count)
                        ;
        } while (test_and_set(val));
}

static inline void atomic_inc(atomic_t *val)
{
        atomic_add(val, 1);
}

static inline void atomic_dec(atomic_t *val)
{
        atomic_add(val, -1);
}

static inline long atomic_preinc(atomic_t *val)
{
        return atomic_add(val, 1) + 1;
}

static inline long atomic_predec(atomic_t *val)
{
        return atomic_add(val, -1) - 1;
}

static inline long atomic_postinc(atomic_t *val)
{
        return atomic_add(val, 1);
}

static inline long atomic_postdec(atomic_t *val)
{
        return atomic_add(val, -1);
}

#endif

/** @}
 */