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/*
* arch-tag: Implementation of atomic integers for Rhythmbox
* Copyright (C) 2002, 2003 Red Hat, Inc.
* Copyright (C) 2003 CodeFactory AB
*
* Licensed under the Academic Free License version 1.2
*
* 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
*
*/
#include "rb-atomic.h"
#ifdef HAVE_GTK_2_3
#error "rb-atomic shouldn't be compiled with GTK+ 2.4, please file a bug on bugzilla.gnome.org"
#else
#ifdef RB_USE_ATOMIC_INT_486
/* Taken from CVS version 1.7 of glibc's sysdeps/i386/i486/atomicity.h */
/* Since the asm stuff here is gcc-specific we go ahead and use "inline" also */
static inline gint32
atomic_exchange_and_add (RBAtomic *atomic,
volatile gint32 val)
{
register gint32 result;
__asm__ __volatile__ ("lock; xaddl %0,%1"
: "=r" (result), "=m" (atomic->value)
: "0" (val), "m" (atomic->value));
return result;
}
#else
GStaticMutex rb_atomic_mutex = G_STATIC_MUTEX_INIT;
#endif
/**
* Atomically increments an integer
*
* @param atomic pointer to the integer to increment
* @returns the value before incrementing
*
* @todo implement arch-specific faster atomic ops
*/
gint32
rb_atomic_inc (RBAtomic *atomic)
{
#ifdef RB_USE_ATOMIC_INT_486
return atomic_exchange_and_add (atomic, 1);
#else
gint32 res;
g_static_mutex_lock (&rb_atomic_mutex);
res = atomic->value;
atomic->value += 1;
g_static_mutex_unlock (&rb_atomic_mutex);
return res;
#endif
}
/**
* Atomically decrement an integer
*
* @param atomic pointer to the integer to decrement
* @returns the value before decrementing
*
* @todo implement arch-specific faster atomic ops
*/
gint32
rb_atomic_dec (RBAtomic *atomic)
{
#ifdef RB_USE_ATOMIC_INT_486
return atomic_exchange_and_add (atomic, -1);
#else
gint32 res;
g_static_mutex_lock (&rb_atomic_mutex);
res = atomic->value;
atomic->value -= 1;
g_static_mutex_unlock (&rb_atomic_mutex);
return res;
#endif
}
#endif /* HAVE_GTK_2_3 */
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