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* Copyright (C) 2006, 2007 Internet Systems Consortium, Inc. ("ISC")
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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* THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
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* REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
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* AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
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* INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
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* LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
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* OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
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* PERFORMANCE OF THIS SOFTWARE.
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/* $Id: atomic.h,v 1.4 2007/06/19 23:47:17 tbox Exp $ */
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#define ISC_ATOMIC_H 1
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#include <isc/platform.h>
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#include <isc/types.h>
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#ifdef ISC_PLATFORM_USEGCCASM
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* This routine atomically increments the value stored in 'p' by 'val', and
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* returns the previous value.
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* Open issue: can 'fetchadd' make the code faster for some particular values
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static inline isc_int32_t
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isc_atomic_xadd(isc_int32_t *p, isc_int32_t val) {
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isc_int32_t prev, swapped;
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for (prev = *(volatile isc_int32_t *)p; ; prev = swapped) {
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"cmpxchg4.acq %0=%4,%3,ar.ccv"
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: "=r" (swapped), "=m" (*p)
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: "r" (prev), "r" (swapped), "m" (*p)
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* This routine atomically stores the value 'val' in 'p'.
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isc_atomic_store(isc_int32_t *p, isc_int32_t val) {
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* This routine atomically replaces the value in 'p' with 'val', if the
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* original value is equal to 'cmpval'. The original value is returned in any
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static inline isc_int32_t
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isc_atomic_cmpxchg(isc_int32_t *p, isc_int32_t cmpval, isc_int32_t val) {
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"cmpxchg4.acq %0=%4,%3,ar.ccv"
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: "=r" (ret), "=m" (*p)
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: "r" (cmpval), "r" (val), "m" (*p)
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#else /* !ISC_PLATFORM_USEGCCASM */
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#error "unsupported compiler. disable atomic ops by --disable-atomic"
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#endif /* ISC_ATOMIC_H */