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/*
* Copyright (C) 2005, 2007 Internet Systems Consortium, Inc. ("ISC")
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
* REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
* INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
* LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
* OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
* PERFORMANCE OF THIS SOFTWARE.
*/
/* $Id: atomic.h,v 1.5 2007/06/19 23:47:18 tbox Exp $ */
/*
* This code was written based on FreeBSD's kernel source whose copyright
* follows:
*/
/*-
* Copyright (c) 1998 Doug Rabson.
* Copyright (c) 2001 Jake Burkholder.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* from: FreeBSD: src/sys/i386/include/atomic.h,v 1.20 2001/02/11
* $FreeBSD: src/sys/sparc64/include/atomic.h,v 1.8 2004/05/22 00:52:16 marius Exp $
*/
#ifndef ISC_ATOMIC_H
#define ISC_ATOMIC_H 1
#include <isc/platform.h>
#include <isc/types.h>
#define ASI_P 0x80 /* Primary Address Space Identifier */
#ifdef ISC_PLATFORM_USEGCCASM
/*
* This routine atomically increments the value stored in 'p' by 'val', and
* returns the previous value.
*/
static inline isc_int32_t
isc_atomic_xadd(isc_int32_t *p, isc_int32_t val) {
isc_int32_t prev, swapped;
for (prev = *(volatile isc_int32_t *)p; ; prev = swapped) {
swapped = prev + val;
__asm__ volatile(
"casa [%1] %2, %3, %0"
: "+r"(swapped)
: "r"(p), "n"(ASI_P), "r"(prev));
if (swapped == prev)
break;
}
return (prev);
}
/*
* This routine atomically stores the value 'val' in 'p'.
*/
static inline void
isc_atomic_store(isc_int32_t *p, isc_int32_t val) {
isc_int32_t prev, swapped;
for (prev = *(volatile isc_int32_t *)p; ; prev = swapped) {
swapped = val;
__asm__ volatile(
"casa [%1] %2, %3, %0"
: "+r"(swapped)
: "r"(p), "n"(ASI_P), "r"(prev)
: "memory");
if (swapped == prev)
break;
}
}
/*
* This routine atomically replaces the value in 'p' with 'val', if the
* original value is equal to 'cmpval'. The original value is returned in any
* case.
*/
static inline isc_int32_t
isc_atomic_cmpxchg(isc_int32_t *p, isc_int32_t cmpval, isc_int32_t val) {
isc_int32_t temp = val;
__asm__ volatile(
"casa [%1] %2, %3, %0"
: "+r"(temp)
: "r"(p), "n"(ASI_P), "r"(cmpval));
return (temp);
}
#else /* ISC_PLATFORM_USEGCCASM */
#error "unsupported compiler. disable atomic ops by --disable-atomic"
#endif /* ISC_PLATFORM_USEGCCASM */
#endif /* ISC_ATOMIC_H */
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