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freebsd/sys/alpha/include/atomic.h
Poul-Henning Kamp 819e370c3b Introduce atomic_cmpset_int() and atomic_cmpset_long() from SMPng a
few hours earlier than the rest.

The next DEVFS commit needs these functions.

Alpha versions by: dfr
i386 versions by: jakeb

Approved by:    SMPng
2000-09-06 11:21:14 +00:00

145 lines
5.0 KiB
C

/*-
* 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 _MACHINE_ATOMIC_H_
#define _MACHINE_ATOMIC_H_
/*
* Various simple arithmetic on memory which is atomic in the presence
* of interrupts and SMP safe.
*/
void atomic_set_8(volatile u_int8_t *, u_int8_t);
void atomic_clear_8(volatile u_int8_t *, u_int8_t);
void atomic_add_8(volatile u_int8_t *, u_int8_t);
void atomic_subtract_8(volatile u_int8_t *, u_int8_t);
void atomic_set_16(volatile u_int16_t *, u_int16_t);
void atomic_clear_16(volatile u_int16_t *, u_int16_t);
void atomic_add_16(volatile u_int16_t *, u_int16_t);
void atomic_subtract_16(volatile u_int16_t *, u_int16_t);
void atomic_set_32(volatile u_int32_t *, u_int32_t);
void atomic_clear_32(volatile u_int32_t *, u_int32_t);
void atomic_add_32(volatile u_int32_t *, u_int32_t);
void atomic_subtract_32(volatile u_int32_t *, u_int32_t);
void atomic_set_64(volatile u_int64_t *, u_int64_t);
void atomic_clear_64(volatile u_int64_t *, u_int64_t);
void atomic_add_64(volatile u_int64_t *, u_int64_t);
void atomic_subtract_64(volatile u_int64_t *, u_int64_t);
#define atomic_set_char atomic_set_8
#define atomic_clear_char atomic_clear_8
#define atomic_add_char atomic_add_8
#define atomic_subtract_char atomic_subtract_8
#define atomic_set_short atomic_set_16
#define atomic_clear_short atomic_clear_16
#define atomic_add_short atomic_add_16
#define atomic_subtract_short atomic_subtract_16
#define atomic_set_int atomic_set_32
#define atomic_clear_int atomic_clear_32
#define atomic_add_int atomic_add_32
#define atomic_subtract_int atomic_subtract_32
#define atomic_set_long atomic_set_64
#define atomic_clear_long atomic_clear_64
#define atomic_add_long atomic_add_64
#define atomic_subtract_long atomic_subtract_64
/*
* Atomically compare the value stored at *p with cmpval and if the
* two values are equal, update the value of *p with newval. Returns
* zero if the compare failed, nonzero otherwise.
*/
static __inline u_int32_t
atomic_cmpset_32(volatile u_int32_t* p, u_int32_t cmpval, u_int32_t newval)
{
u_int32_t ret, temp;
__asm __volatile (
"1:\tldl_l %1, %5\n\t" /* load old value */
"cmpeq %1, %3, %0\n\t" /* compare */
"beq %0, 2f\n\t" /* exit if not equal */
"mov %4, %1\n\t" /* value to store */
"stl_c %1, %2\n\t" /* attempt to store */
"beq %1, 3f\n\t" /* if it failed, spin */
"2:\n" /* done */
".section .text3,\"ax\"\n" /* improve branch prediction */
"3:\tbr 1b\n" /* try again */
".previous\n"
: "=&r" (ret), "=r" (temp), "=m" (*p)
: "r" (cmpval), "r" (newval), "m" (*p)
: "memory");
return ret;
}
/*
* Atomically compare the value stored at *p with cmpval and if the
* two values are equal, update the value of *p with newval. Returns
* zero if the compare failed, nonzero otherwise.
*/
static __inline u_int64_t
atomic_cmpset_64(volatile u_int64_t* p, u_int64_t cmpval, u_int64_t newval)
{
u_int64_t ret, temp;
__asm __volatile (
"1:\tldq_l %1, %5\n\t" /* load old value */
"cmpeq %1, %3, %0\n\t" /* compare */
"beq %0, 2f\n\t" /* exit if not equal */
"mov %4, %1\n\t" /* value to store */
"stq_c %1, %2\n\t" /* attempt to store */
"beq %1, 3f\n\t" /* if it failed, spin */
"2:\n" /* done */
".section .text3,\"ax\"\n" /* improve branch prediction */
"3:\tbr 1b\n" /* try again */
".previous\n"
: "=&r" (ret), "=r" (temp), "=m" (*p)
: "r" (cmpval), "r" (newval), "m" (*p)
: "memory");
return ret;
}
#define atomic_cmpset_int atomic_cmpset_32
#define atomic_cmpset_long atomic_cmpset_64
static __inline int
atomic_cmpset_ptr(volatile void *dst, void *exp, void *src)
{
return (
atomic_cmpset_long((volatile u_long *)dst, (u_long)exp, (u_long)src));
}
#endif /* ! _MACHINE_ATOMIC_H_ */