/contrib/bind9/lib/isc/alpha/include/isc/atomic.h
https://bitbucket.org/freebsd/freebsd-head/ · C Header · 184 lines · 102 code · 21 blank · 61 comment · 0 complexity · c4ccfcbefa57b38bb23c03be9932e3f8 MD5 · raw file
- /*
- * 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.
- *
- * $FreeBSD$
- */
- #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 */