/*
* 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 1.7 2009/04/08 06:48:23 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: 258945 2013-12-04 21:33:17Z roberto $
*/
#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 */