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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.

 */

/** @addtogroup ia32

 * @{

 */

/** @file

 */

#ifndef KERN_ia32_ATOMIC_H_

#define KERN_ia32_ATOMIC_H_

#include <arch/types.h>

#include <arch/barrier.h>

#include <preemption.h>

static inline void atomic_inc(atomic_t *val) {

#ifdef CONFIG_SMP

	asm volatile (

		"lock incl %[count]\n"

		: [count] "+m" (val->count)

	);

#else

	asm volatile (

		"incl %[count]\n"

		: [count] "+m" (val->count)

	);

#endif /* CONFIG_SMP */

}

static inline void atomic_dec(atomic_t *val) {

#ifdef CONFIG_SMP

	asm volatile (

		"lock decl %[count]\n"

		: [count] "+m" (val->count)

	);

#else

	asm volatile (

		"decl %[count]\n"

		: "+m" (val->count)

	);

#endif /* CONFIG_SMP */

}

static inline long atomic_postinc(atomic_t *val) 

{

	long r = 1;

	asm volatile (

		"lock xaddl %[r], %[count]\n"

		: [count] "+m" (val->count), [r] "+r" (r)

	);

	return r;

}

static inline long atomic_postdec(atomic_t *val) 

{

	long 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)

static inline uint32_t test_and_set(atomic_t *val) {

	uint32_t v;

	asm volatile (

		"movl $1, %[v]\n"

		"xchgl %[v], %[count]\n"

		: [v] "=r" (v), [count] "+m" (val->count)

	);

	return v;

}

/** ia32 specific fast spinlock */

static inline void atomic_lock_arch(atomic_t *val)

{

	uint32_t tmp;

	preemption_disable();

	asm volatile (

		"0:\n"

#ifdef CONFIG_HT

		"pause\n"        /* Pentium 4's HT love this instruction */

#endif

		"mov %[count], %[tmp]\n"

		"testl %[tmp], %[tmp]\n"

		"jnz 0b\n"       /* lightweight looping on locked spinlock */

		"incl %[tmp]\n"  /* now use the atomic operation */

		"xchgl %[count], %[tmp]\n"

		"testl %[tmp], %[tmp]\n"

		"jnz 0b\n"

		: [count] "+m" (val->count), [tmp] "=&r" (tmp)

	);

	/*

	 * Prevent critical section code from bleeding out this way up.

	 */

	CS_ENTER_BARRIER();

}

#endif

/** @}

 */