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atomic_sub_64_cas.c revision 1.2.4.2 
      1  1.2.4.2  yamt /*	$NetBSD: atomic_sub_64_cas.c,v 1.2.4.2 2014/05/22 11:26:30 yamt Exp $	*/
      2  1.2.4.2  yamt 
      3  1.2.4.2  yamt /*-
      4  1.2.4.2  yamt  * Copyright (c) 2014 The NetBSD Foundation, Inc.
      5  1.2.4.2  yamt  * All rights reserved.
      6  1.2.4.2  yamt  *
      7  1.2.4.2  yamt  * This code is derived from software contributed to The NetBSD Foundation
      8  1.2.4.2  yamt  * by Jason R. Thorpe.
      9  1.2.4.2  yamt  *
     10  1.2.4.2  yamt  * Redistribution and use in source and binary forms, with or without
     11  1.2.4.2  yamt  * modification, are permitted provided that the following conditions
     12  1.2.4.2  yamt  * are met:
     13  1.2.4.2  yamt  * 1. Redistributions of source code must retain the above copyright
     14  1.2.4.2  yamt  *    notice, this list of conditions and the following disclaimer.
     15  1.2.4.2  yamt  * 2. Redistributions in binary form must reproduce the above copyright
     16  1.2.4.2  yamt  *    notice, this list of conditions and the following disclaimer in the
     17  1.2.4.2  yamt  *    documentation and/or other materials provided with the distribution.
     18  1.2.4.2  yamt  *
     19  1.2.4.2  yamt  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  1.2.4.2  yamt  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  1.2.4.2  yamt  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  1.2.4.2  yamt  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  1.2.4.2  yamt  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  1.2.4.2  yamt  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  1.2.4.2  yamt  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  1.2.4.2  yamt  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  1.2.4.2  yamt  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  1.2.4.2  yamt  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  1.2.4.2  yamt  * POSSIBILITY OF SUCH DAMAGE.
     30  1.2.4.2  yamt  */
     31  1.2.4.2  yamt 
     32  1.2.4.2  yamt #include <sys/atomic.h>
     33  1.2.4.2  yamt 
     34  1.2.4.2  yamt #ifdef __HAVE_ATOMIC64_OPS
     35  1.2.4.2  yamt 
     36  1.2.4.2  yamt uint64_t fetch_and_sub_8(volatile uint64_t *, uint64_t, ...)
     37  1.2.4.2  yamt     asm("__sync_fetch_and_sub_8");
     38  1.2.4.2  yamt uint64_t sub_and_fetch_8(volatile uint64_t *, uint64_t, ...)
     39  1.2.4.2  yamt     asm("__sync_sub_and_fetch_8");
     40  1.2.4.2  yamt 
     41  1.2.4.2  yamt uint64_t
     42  1.2.4.2  yamt fetch_and_sub_8(volatile uint64_t *addr, uint64_t val, ...)
     43  1.2.4.2  yamt {
     44  1.2.4.2  yamt 	uint64_t old, new;
     45  1.2.4.2  yamt 
     46  1.2.4.2  yamt 	do {
     47  1.2.4.2  yamt 		old = *addr;
     48  1.2.4.2  yamt 		new = old - val;
     49  1.2.4.2  yamt 	} while (atomic_cas_64(addr, old, new) != old);
     50  1.2.4.2  yamt 	return old;
     51  1.2.4.2  yamt }
     52  1.2.4.2  yamt 
     53  1.2.4.2  yamt uint64_t
     54  1.2.4.2  yamt sub_and_fetch_8(volatile uint64_t *addr, uint64_t val, ...)
     55  1.2.4.2  yamt {
     56  1.2.4.2  yamt 	uint64_t old, new;
     57  1.2.4.2  yamt 
     58  1.2.4.2  yamt 	do {
     59  1.2.4.2  yamt 		old = *addr;
     60  1.2.4.2  yamt 		new = old - val;
     61  1.2.4.2  yamt 	} while (atomic_cas_64(addr, old, new) != old);
     62  1.2.4.2  yamt 	return new;
     63  1.2.4.2  yamt }
     64  1.2.4.2  yamt 
     65  1.2.4.2  yamt #endif
     66