/* * Copyright (C) 2005, 2007, 2009 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 1.5.332.2 2009/04/08 06:47:32 tbox Exp $ */ /* * This code was written based on FreeBSD's kernel source whose copyright * follows: */ /*- * Copyright (c) 1998 Doug Rabson * 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. * * $FreeBSD: src/sys/alpha/include/atomic.h,v 1.18.6.1 2004/09/13 21:52:04 wilko Exp $ */ #ifndef ISC_ATOMIC_H #define ISC_ATOMIC_H 1 #include <isc/platform.h> #include <isc/types.h> #ifdef ISC_PLATFORM_USEOSFASM #include <c_asm.h> #pragma intrinsic(asm) /* * This routine atomically increments the value stored in 'p' by 'val', and * returns the previous value. Memory access ordering around this function * can be critical, so we add explicit memory block instructions at the * beginning and the end of it (same for other functions). */ static inline isc_int32_t isc_atomic_xadd(isc_int32_t *p, isc_int32_t val) { return (asm("mb;" "1:" "ldl_l %t0, 0(%a0);" /* load old value */ "mov %t0, %v0;" /* copy the old value */ "addl %t0, %a1, %t0;" /* calculate new value */ "stl_c %t0, 0(%a0);" /* attempt to store */ "beq %t0, 1b;" /* spin if failed */ "mb;", p, val)); } /* * This routine atomically stores the value 'val' in 'p'. */ static inline void isc_atomic_store(isc_int32_t *p, isc_int32_t val) { (void)asm("mb;" "1:" "ldl_l %t0, 0(%a0);" /* load old value */ "mov %a1, %t0;" /* value to store */ "stl_c %t0, 0(%a0);" /* attempt to store */ "beq %t0, 1b;" /* spin if failed */ "mb;", p, val); } /* * 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) { return(asm("mb;" "1:" "ldl_l %t0, 0(%a0);" /* load old value */ "mov %t0, %v0;" /* copy the old value */ "cmpeq %t0, %a1, %t0;" /* compare */ "beq %t0, 2f;" /* exit if not equal */ "mov %a2, %t0;" /* value to store */ "stl_c %t0, 0(%a0);" /* attempt to store */ "beq %t0, 1b;" /* if it failed, spin */ "2:" "mb;", p, cmpval, val)); } #elif defined (ISC_PLATFORM_USEGCCASM) static inline isc_int32_t isc_atomic_xadd(isc_int32_t *p, isc_int32_t val) { isc_int32_t temp, prev; __asm__ volatile( "mb;" "1:" "ldl_l %0, %1;" /* load old value */ "mov %0, %2;" /* copy the old value */ "addl %0, %3, %0;" /* calculate new value */ "stl_c %0, %1;" /* attempt to store */ "beq %0, 1b;" /* spin if failed */ "mb;" : "=&r"(temp), "+m"(*p), "=&r"(prev) : "r"(val) : "memory"); return (prev); } static inline void isc_atomic_store(isc_int32_t *p, isc_int32_t val) { isc_int32_t temp; __asm__ volatile( "mb;" "1:" "ldl_l %0, %1;" /* load old value */ "mov %2, %0;" /* value to store */ "stl_c %0, %1;" /* attempt to store */ "beq %0, 1b;" /* if it failed, spin */ "mb;" : "=&r"(temp), "+m"(*p) : "r"(val) : "memory"); } static inline isc_int32_t isc_atomic_cmpxchg(isc_int32_t *p, isc_int32_t cmpval, isc_int32_t val) { isc_int32_t temp, prev; __asm__ volatile( "mb;" "1:" "ldl_l %0, %1;" /* load old value */ "mov %0, %2;" /* copy the old value */ "cmpeq %0, %3, %0;" /* compare */ "beq %0, 2f;" /* exit if not equal */ "mov %4, %0;" /* value to store */ "stl_c %0, %1;" /* attempt to store */ "beq %0, 1b;" /* if it failed, spin */ "2:" "mb;" : "=&r"(temp), "+m"(*p), "=&r"(prev) : "r"(cmpval), "r"(val) : "memory"); return (prev); } #else #error "unsupported compiler. disable atomic ops by --disable-atomic" #endif #endif /* ISC_ATOMIC_H */