cmpxchg.h

Go to the documentation of this file.

/****
 Active Objects v4.2
 Copyright (C) 2006-2010 Werner Van Belle
 http://active.yellowcouch.org/

 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
****/
#ifndef __loaded__cmpxchg_h__
#define __loaded__cmpxchg_h__
using namespace std;
#line 1 "cmpxchg.h++"

#ifndef __HAVE_ARCH_CMPXCHG
#ifdef CONFIG_SMP
#define LOCK_PREFIX \
                ".section .smp_locks,\"a\"\n"   \
                "  .align 8\n"                  \
                "  .quad 661f\n" /* address */  \
                ".previous\n"                   \
                "661:\n\tlock; "
#else /* ! CONFIG_SMP */
#define LOCK_PREFIX ""
#endif

#define __xg(x) ((volatile long *)(x))

static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
                                      unsigned long nieuw, int size)
{
        unsigned long prev;
        switch (size) {
        case 1:
                __asm__ __volatile__(LOCK_PREFIX "cmpxchg %b1,%2"
                                     : "=a"(prev)
                                     : "q"(nieuw), "m"(*__xg(ptr)), "0"(old)
                                     : "memory");
                return prev;
        case 2:
                __asm__ __volatile__(LOCK_PREFIX "cmpxchg %w1,%2"
                                     : "=a"(prev)
                                     : "r"(nieuw), "m"(*__xg(ptr)), "0"(old)
                                     : "memory");
                return prev;
        case 4:
                __asm__ __volatile__(LOCK_PREFIX "cmpxchg %k1,%2"
                                     : "=a"(prev)
                                     : "r"(nieuw), "m"(*__xg(ptr)), "0"(old)
                                     : "memory");
                return prev;
        case 8:
                __asm__ __volatile__(LOCK_PREFIX "cmpxchg %1,%2"
                                     : "=a"(prev)
                                     : "r"(nieuw), "m"(*__xg(ptr)), "0"(old)
                                     : "memory");
                return prev;
        }
        return old;
}

#define cmpxchg(ptr,o,n)\
   ((__typeof__(*(ptr)))__cmpxchg((ptr),(unsigned long)(o),\
                                     (unsigned long)(n),sizeof(*(ptr))))
#endif
#endif // __loaded__cmpxchg_h__

---