gstreamer/gst/gstatomic.h
Wim Taymans 6fc49a76a1 Let's take the performance hit (cache flush) on UP and make it work on SMP too. (thanks to Cameron Hutchison)
Original commit message from CVS:
Let's take the performance hit (cache flush) on UP and make it work
on SMP too. (thanks to Cameron Hutchison)
2002-09-05 22:21:45 +00:00

213 lines
6.1 KiB
C

/* GStreamer
* Copyright (C) <1999> Erik Walthinsen <omega@cse.ogi.edu>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library 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.
*/
#ifndef __GST_ATOMIC_H__
#define __GST_ATOMIC_H__
/* FIXME */
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#ifdef HAVE_ATOMIC_H
# include <asm/atomic.h>
#endif
#include <glib.h>
G_BEGIN_DECLS
typedef struct _GstAtomicInt GstAtomicInt;
struct _GstAtomicInt {
#ifdef HAVE_ATOMIC_H
union {
atomic_t value;
struct {
int value;
GMutex *lock;
} unused;
} v;
#else
int value;
GMutex *lock;
#endif
};
#ifdef HAVE_ATOMIC_H
/* atomic functions */
#define GST_ATOMIC_INT_INIT(ref, val) (atomic_set(&((ref)->v.value), (val)))
#define GST_ATOMIC_INT_FREE(ref)
#define GST_ATOMIC_INT_SET(ref,val) (atomic_set(&((ref)->v.value), (val)))
#define GST_ATOMIC_INT_VALUE(ref) (atomic_read(&((ref)->v.value)))
#define GST_ATOMIC_INT_READ(ref,res) (*res = atomic_read(&((ref)->v.value)))
#define GST_ATOMIC_INT_INC(ref) (atomic_inc (&((ref)->v.value)))
#define GST_ATOMIC_INT_DEC_AND_TEST(ref,zero) (*zero = atomic_dec_and_test (&((ref)->v.value)))
#define GST_ATOMIC_INT_ADD(ref, count) (atomic_add ((count), &((ref)->v.value)))
#else
/* fallback using a lock */
#define GST_ATOMIC_INT_INIT(ref, val) \
G_STMT_START { \
(ref)->value = (val); \
(ref)->lock = g_mutex_new(); \
} G_STMT_END
#define GST_ATOMIC_INT_FREE(ref) g_mutex_free ((ref)->lock)
#define GST_ATOMIC_INT_SET(ref,val) \
G_STMT_START { \
g_mutex_lock ((ref)->lock); \
(ref)->value = (val); \
g_mutex_unlock ((ref)->lock); \
} G_STMT_END
#define GST_ATOMIC_INT_VALUE(ref) ((ref)->value)
#define GST_ATOMIC_INT_READ(ref,res) \
G_STMT_START { \
g_mutex_lock ((ref)->lock); \
*res = (ref)->value; \
g_mutex_unlock ((ref)->lock); \
} G_STMT_END
#define GST_ATOMIC_INT_INC(ref) \
G_STMT_START { \
g_mutex_lock ((ref)->lock); \
(ref)->value++; \
g_mutex_unlock ((ref)->lock); \
} G_STMT_END
#define GST_ATOMIC_INT_DEC_AND_TEST(ref,zero) \
G_STMT_START { \
g_mutex_lock ((ref)->lock); \
(ref)->value--; \
*zero = ((ref)->value == 0); \
g_mutex_unlock ((ref)->lock); \
} G_STMT_END
#define GST_ATOMIC_INT_ADD(ref, count) \
G_STMT_START { \
g_mutex_lock ((ref)->lock); \
(ref)->value += count; \
g_mutex_unlock ((ref)->lock); \
} G_STMT_END
#endif /* HAVE_ATOMIC_H */
typedef struct _GstAtomicSwap GstAtomicSwap;
#define GST_ATOMIC_SWAP_VALUE(swap) ((swap)->value)
struct _GstAtomicSwap {
volatile gpointer value;
volatile gulong cnt; /* for the ABA problem */
GMutex *lock; /* lock for C fallback */
};
#if defined (__i386__) && defined (__GNUC__) && __GNUC__ >= 2
#define GST_ATOMIC_LOCK "lock ; "
#define _GST_ATOMIC_SWAP_INIT(swap,val) \
G_STMT_START { \
(swap)->value = (gpointer)(val); \
(swap)->cnt = 0; \
} G_STMT_END
#define _GST_ATOMIC_SWAP(swap, val) \
G_STMT_START { \
__asm__ __volatile__ ("1:" \
" movl %2, (%1);" \
GST_ATOMIC_LOCK "cmpxchg %1, %0;" \
" jnz 1b;" \
: \
: "m" (*swap), \
"r" (val), \
"a" ((swap)->value)); \
} G_STMT_END
#define _GST_ATOMIC_SWAP_GET(swap, val, res) \
G_STMT_START { \
__asm__ __volatile__ (" testl %%eax, %%eax;" \
" jz 20f;" \
"10:" \
" movl (%%eax), %%ebx;" \
" movl %%edx, %%ecx;" \
" incl %%ecx;" \
GST_ATOMIC_LOCK "cmpxchg8b %1;" \
" jnz 10b;" \
"20:\t" \
: "=a" (*res) \
: "m" (*(swap)), \
"a" (val), \
"d" ((swap)->cnt) \
: "ecx", "ebx"); \
} G_STMT_END
#else
#define _GST_ATOMIC_SWAP_INIT(swap,val) \
G_STMT_START { \
(swap)->lock = g_mutex_new(); \
(swap)->value = (gpointer)val; \
} G_STMT_END
#define _GST_ATOMIC_SWAP(swap, val) \
G_STMT_START { \
gpointer tmp; \
g_mutex_lock ((swap)->lock); \
tmp = (swap)->value; \
(swap)->value = val; \
((gpointer)*val) = tmp; \
g_mutex_unlock ((swap)->lock); \
} G_STMT_END
#define _GST_ATOMIC_SWAP_GET(swap, val, res) \
G_STMT_START { \
if (val) { \
gpointer tmp; \
gint *tmp2; /* this is pretty EVIL */ \
g_mutex_lock ((swap)->lock); \
tmp = (swap)->value; \
tmp2 = val; \
(swap)->value = (gpointer)*tmp2; \
(*res) = (gpointer)*tmp2 = tmp; \
g_mutex_unlock ((swap)->lock); \
} \
} G_STMT_END
#endif
/* initialize the swap structure with an initial value */
#define GST_ATOMIC_SWAP_INIT(swap,val) _GST_ATOMIC_SWAP_INIT(swap, val)
/* atomically swap the contents the swap value with the value pointed to
* by val. */
#define GST_ATOMIC_SWAP(swap, val) _GST_ATOMIC_SWAP(swap, val)
/* atomically swap the contents the swap value with the value pointed to
* by val. The new value of the swap value is returned in the memory pointed
* to by res */
#define GST_ATOMIC_SWAP_GET(swap,val,res) _GST_ATOMIC_SWAP_GET(swap, val, res)
G_END_DECLS
#endif /* __GST_ATOMIC_H__ */