arch/ppc32/include/atomic.h

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00001 /*
00002  * Copyright (C) 2005 Martin Decky
00003  * All rights reserved.
00004  *
00005  * Redistribution and use in source and binary forms, with or without
00006  * modification, are permitted provided that the following conditions
00007  * are met:
00008  *
00009  * - Redistributions of source code must retain the above copyright
00010  *   notice, this list of conditions and the following disclaimer.
00011  * - Redistributions in binary form must reproduce the above copyright
00012  *   notice, this list of conditions and the following disclaimer in the
00013  *   documentation and/or other materials provided with the distribution.
00014  * - The name of the author may not be used to endorse or promote products
00015  *   derived from this software without specific prior written permission.
00016  *
00017  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
00018  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
00019  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
00020  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
00021  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
00022  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
00023  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
00024  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
00025  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
00026  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
00027  */
00028 
00035 #ifndef __ppc32_ATOMIC_H__
00036 #define __ppc32_ATOMIC_H__
00037 
00038 static inline void atomic_inc(atomic_t *val)
00039 {
00040         long tmp;
00041 
00042         asm __volatile__ (
00043                 "1:\n"
00044                 "lwarx %0, 0, %2\n"
00045                 "addic %0, %0, 1\n"
00046                 "stwcx. %0, 0, %2\n"
00047                 "bne- 1b"
00048                 : "=&r" (tmp), "=m" (val->count)
00049                 : "r" (&val->count), "m" (val->count)
00050                 : "cc");
00051 }
00052 
00053 static inline void atomic_dec(atomic_t *val)
00054 {
00055         long tmp;
00056 
00057         asm __volatile__(
00058                 "1:\n"
00059                 "lwarx %0, 0, %2\n"
00060                 "addic %0, %0, -1\n"
00061                 "stwcx. %0, 0, %2\n"
00062                 "bne- 1b"
00063                 : "=&r" (tmp), "=m" (val->count)
00064                 : "r" (&val->count), "m" (val->count)
00065                 : "cc");
00066 }
00067 
00068 static inline long atomic_postinc(atomic_t *val)
00069 {
00070         atomic_inc(val);
00071         return val->count - 1;
00072 }
00073 
00074 static inline long atomic_postdec(atomic_t *val)
00075 {
00076         atomic_dec(val);
00077         return val->count + 1;
00078 }
00079 
00080 static inline long atomic_preinc(atomic_t *val)
00081 {
00082         atomic_inc(val);
00083         return val->count;
00084 }
00085 
00086 static inline long atomic_predec(atomic_t *val)
00087 {
00088         atomic_dec(val);
00089         return val->count;
00090 }
00091 
00092 #endif
00093 

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