1 /* $NetBSD: atomic.h,v 1.6 2014/12/10 04:38:00 christos Exp $ */ 2 3 /* 4 * Copyright (C) 2005, 2007 Internet Systems Consortium, Inc. ("ISC") 5 * 6 * Permission to use, copy, modify, and/or distribute this software for any 7 * purpose with or without fee is hereby granted, provided that the above 8 * copyright notice and this permission notice appear in all copies. 9 * 10 * THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH 11 * REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY 12 * AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT, 13 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM 14 * LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE 15 * OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR 16 * PERFORMANCE OF THIS SOFTWARE. 17 */ 18 19 /* Id: atomic.h,v 1.4 2007/06/19 23:47:18 tbox Exp */ 20 21 #ifndef ISC_ATOMIC_H 22 #define ISC_ATOMIC_H 1 23 24 #include <isc/platform.h> 25 #include <isc/types.h> 26 27 /* XXX: These are not atomic! */ 28 /* 29 * This routine atomically increments the value stored in 'p' by 'val', and 30 * returns the previous value. 31 */ 32 static __inline isc_int32_t 33 isc_atomic_xadd(isc_int32_t *p, isc_int32_t val) { 34 isc_int32_t prev = *p; 35 36 *p += val; 37 38 return prev; 39 } 40 41 /* 42 * This routine atomically stores the value 'val' in 'p'. 43 */ 44 static __inline void 45 isc_atomic_store(isc_int32_t *p, isc_int32_t val) { 46 *p = val; 47 } 48 49 /* 50 * This routine atomically replaces the value in 'p' with 'val', if the 51 * original value is equal to 'cmpval'. The original value is returned in any 52 * case. 53 */ 54 static __inline isc_int32_t 55 isc_atomic_cmpxchg(isc_int32_t *p, isc_int32_t cmpval, isc_int32_t val) { 56 isc_int32_t prev = *p; 57 58 if (*p == cmpval) 59 *p = val; 60 61 return prev; 62 } 63 64 #endif /* ISC_ATOMIC_H */ 65