oro_atomic.h

/***************************************************************************
  tag: Peter Soetens  Mon Jan 10 15:59:15 CET 2005  oro_atomic.h 

                        oro_atomic.h -  description
                           -------------------
    begin                : Mon January 10 2005
    copyright            : (C) 2005 Peter Soetens
    email                : peter.soetens@mech.kuleuven.ac.be
 
 ***************************************************************************
 *   This library 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;                 *
 *   version 2 of the License.                                             *
 *                                                                         *
 *   As a special exception, you may use this file as part of a free       *
 *   software library without restriction.  Specifically, if other files   *
 *   instantiate templates or use macros or inline functions from this     *
 *   file, or you compile this file and link it with other files to        *
 *   produce an executable, this file does not by itself cause the         *
 *   resulting executable to be covered by the GNU General Public          *
 *   License.  This exception does not however invalidate any other        *
 *   reasons why the executable file might be covered by the GNU General   *
 *   Public License.                                                       *
 *                                                                         *
 *   This library 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     *
 *   Lesser General Public License for more details.                       *
 *                                                                         *
 *   You should have received a copy of the GNU General Public             *
 *   License along with this library; if not, write to the Free Software   *
 *   Foundation, Inc., 59 Temple Place,                                    *
 *   Suite 330, Boston, MA  02111-1307  USA                                *
 *                                                                         *
 ***************************************************************************/
 
 

#include "../../rtt-config.h"
#ifndef __ARCH_I386_ORO_ATOMIC__
#define __ARCH_I386_ORO_ATOMIC__

/*
 * Atomic operations that C can't guarantee us.  Useful for
 * resource counting etc..
 */

#ifndef CONFIG_FORCE_UP
#define ORO_LOCK "lock ; "
#else
#define ORO_LOCK ""
#endif

/*
 * Make sure gcc doesn't try to be clever and move things around
 * on us. We need to use _exactly_ the address the user gave us,
 * not some alias that contains the same information.
 */
typedef struct { volatile int counter; } oro_atomic_t;

#define ORO_ATOMIC_INIT(i)  { (i) }
#define ORO_ATOMIC_SETUP    oro_atomic_set
#define ORO_ATOMIC_CLEANUP(v)   

#define oro_atomic_read(v)      ((v)->counter)

#define oro_atomic_set(v,i)     (((v)->counter) = (i))

static __inline__ void oro_atomic_add(int i, oro_atomic_t *v)
{
    __asm__ __volatile__(
        ORO_LOCK "addl %1,%0"
        :"=m" (v->counter)
        :"ir" (i), "m" (v->counter));
}

static __inline__ void oro_atomic_sub(int i, oro_atomic_t *v)
{
    __asm__ __volatile__(
        ORO_LOCK "subl %1,%0"
        :"=m" (v->counter)
        :"ir" (i), "m" (v->counter));
}

static __inline__ int oro_atomic_sub_and_test(int i, oro_atomic_t *v)
{
    unsigned char c;

    __asm__ __volatile__(
        ORO_LOCK "subl %2,%0; sete %1"
        :"=m" (v->counter), "=qm" (c)
        :"ir" (i), "m" (v->counter) : "memory");
    return c;
}

static __inline__ void oro_atomic_inc(oro_atomic_t *v)
{
    __asm__ __volatile__(
        ORO_LOCK "incl %0"
        :"=m" (v->counter)
        :"m" (v->counter));
}

static __inline__ void oro_atomic_dec(oro_atomic_t *v)
{
    __asm__ __volatile__(
        ORO_LOCK "decl %0"
        :"=m" (v->counter)
        :"m" (v->counter));
}

static __inline__ int oro_atomic_dec_and_test(oro_atomic_t *v)
{
    unsigned char c;

    __asm__ __volatile__(
        ORO_LOCK "decl %0; sete %1"
        :"=m" (v->counter), "=qm" (c)
        :"m" (v->counter) : "memory");
    return c != 0;
}

static __inline__ int oro_atomic_inc_and_test(oro_atomic_t *v)
{
    unsigned char c;

    __asm__ __volatile__(
        ORO_LOCK "incl %0; sete %1"
        :"=m" (v->counter), "=qm" (c)
        :"m" (v->counter) : "memory");
    return c != 0;
}

static __inline__ int oro_atomic_add_negative(int i, oro_atomic_t *v)
{
    unsigned char c;

    __asm__ __volatile__(
        ORO_LOCK "addl %2,%0; sets %1"
        :"=m" (v->counter), "=qm" (c)
        :"ir" (i), "m" (v->counter) : "memory");
    return c;
}

/* These are x86-specific, used by some header files */
#define oro_atomic_clear_mask(mask, addr) \
__asm__ __volatile__(ORO_LOCK "andl %0,%1" \
: : "r" (~(mask)),"m" (*addr) : "memory")

#define oro_atomic_set_mask(mask, addr) \
__asm__ __volatile__(ORO_LOCK "orl %0,%1" \
: : "r" (mask),"m" (*(addr)) : "memory")

/* Atomic operations are already serializing on x86 */
#define smp_mb__before_oro_atomic_dec() barrier()
#define smp_mb__after_oro_atomic_dec()  barrier()
#define smp_mb__before_oro_atomic_inc() barrier()
#define smp_mb__after_oro_atomic_inc()  barrier()

#undef ORO_LOCK
#endif