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freebsd-dev/sys/sparc64/include/atomic.h

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/*-
* Copyright (c) 1998 Doug Rabson.
* Copyright (c) 2001 Jake Burkholder.
* 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.
*
* from: FreeBSD: src/sys/i386/include/atomic.h,v 1.20 2001/02/11
* $FreeBSD$
*/
#ifndef _MACHINE_ATOMIC_H_
#define _MACHINE_ATOMIC_H_
#include <machine/cpufunc.h>
/*
* Various simple arithmetic on memory which is atomic in the presence
* of interrupts and multiple processors. See atomic(9) for details.
* Note that efficient hardware support exists only for the 32 and 64
* bit variants; the 8 and 16 bit versions are not provided and should
* not be used in MI code.
*
* This implementation takes advantage of the fact that the sparc64
* cas instruction is both a load and a store. The loop is often coded
* as follows:
*
* do {
* expect = *p;
* new = expect + 1;
* } while (cas(p, expect, new) != expect);
*
* which performs an unnnecessary load on each iteration that the cas
* operation fails. Modified as follows:
*
* expect = *p;
* for (;;) {
* new = expect + 1;
* result = cas(p, expect, new);
* if (result == expect)
* break;
* expect = result;
* }
*
* the return value of cas is used to avoid the extra reload. At the
* time of writing, with gcc version 2.95.3, the branch for the if
* statement is predicted incorrectly as not taken, rather than taken.
* It is expected that the branch prediction hints available in gcc 3.0,
* __builtin_expect, will allow better code to be generated.
*
* The memory barriers provided by the acq and rel variants are intended
* to be sufficient for use of relaxed memory ordering. Due to the
* suggested assembly syntax of the membar operands containing a #
* character, they cannot be used in macros. The cmask and mmask bits
* are hard coded in machine/cpufunc.h and used here through macros.
* Hopefully sun will choose not to change the bit numbers.
*/
#define itype(sz) u_int ## sz ## _t
#define atomic_cas_32(p, e, s) casa(p, e, s, ASI_N)
#define atomic_cas_64(p, e, s) casxa(p, e, s, ASI_N)
#define atomic_cas(p, e, s, sz) \
atomic_cas_ ## sz(p, e, s)
#define atomic_cas_acq(p, e, s, sz) ({ \
itype(sz) v; \
v = atomic_cas(p, e, s, sz); \
membar(LoadLoad | LoadStore); \
v; \
})
#define atomic_cas_rel(p, e, s, sz) ({ \
itype(sz) v; \
membar(LoadStore | StoreStore); \
v = atomic_cas(p, e, s, sz); \
v; \
})
#define atomic_op(p, op, v, sz) do { \
itype(sz) e, r, s; \
for (e = *(volatile itype(sz) *)p;; e = r) { \
s = e op v; \
r = atomic_cas_ ## sz(p, e, s); \
if (r == e) \
break; \
} \
} while (0)
#define atomic_op_acq(p, op, v, sz) do { \
atomic_op(p, op, v, sz); \
membar(LoadLoad | LoadStore); \
} while (0)
#define atomic_op_rel(p, op, v, sz) do { \
membar(LoadStore | StoreStore); \
atomic_op(p, op, v, sz); \
} while (0)
#define atomic_load(p, sz) \
atomic_cas(p, 0, 0, sz)
#define atomic_load_acq(p, sz) ({ \
itype(sz) v; \
v = atomic_load(p, sz); \
membar(LoadLoad | LoadStore); \
v; \
})
#define atomic_load_clear(p, sz) ({ \
itype(sz) e, r; \
for (e = *(volatile itype(sz) *)p;; e = r) { \
r = atomic_cas(p, e, 0, sz); \
if (r == e) \
break; \
} \
e; \
})
#define atomic_store(p, v, sz) do { \
itype(sz) e, r; \
for (e = *(volatile itype(sz) *)p;; e = r) { \
r = atomic_cas(p, e, v, sz); \
if (r == e) \
break; \
} \
} while (0)
#define atomic_store_rel(p, v, sz) do { \
membar(LoadStore | StoreStore); \
atomic_store(p, v, sz); \
} while (0)
#define ATOMIC_GEN(name, ptype, vtype, atype, sz) \
\
static __inline void \
atomic_add_ ## name(volatile ptype p, atype v) \
{ \
atomic_op(p, +, v, sz); \
} \
static __inline void \
atomic_add_acq_ ## name(volatile ptype p, atype v) \
{ \
atomic_op_acq(p, +, v, sz); \
} \
static __inline void \
atomic_add_rel_ ## name(volatile ptype p, atype v) \
{ \
atomic_op_rel(p, +, v, sz); \
} \
\
static __inline void \
atomic_clear_ ## name(volatile ptype p, atype v) \
{ \
atomic_op(p, &, ~v, sz); \
} \
static __inline void \
atomic_clear_acq_ ## name(volatile ptype p, atype v) \
{ \
atomic_op_acq(p, &, ~v, sz); \
} \
static __inline void \
atomic_clear_rel_ ## name(volatile ptype p, atype v) \
{ \
atomic_op_rel(p, &, ~v, sz); \
} \
\
static __inline int \
atomic_cmpset_ ## name(volatile ptype p, vtype e, vtype s) \
{ \
return (((vtype)atomic_cas(p, e, s, sz)) == e); \
} \
static __inline int \
atomic_cmpset_acq_ ## name(volatile ptype p, vtype e, vtype s) \
{ \
return (((vtype)atomic_cas_acq(p, e, s, sz)) == e); \
} \
static __inline int \
atomic_cmpset_rel_ ## name(volatile ptype p, vtype e, vtype s) \
{ \
return (((vtype)atomic_cas_rel(p, e, s, sz)) == e); \
} \
\
static __inline vtype \
atomic_load_ ## name(volatile ptype p) \
{ \
return ((vtype)atomic_cas(p, 0, 0, sz)); \
} \
static __inline vtype \
atomic_load_acq_ ## name(volatile ptype p) \
{ \
return ((vtype)atomic_cas_acq(p, 0, 0, sz)); \
} \
\
static __inline vtype \
atomic_readandclear_ ## name(volatile ptype p) \
{ \
return ((vtype)atomic_load_clear(p, sz)); \
} \
\
static __inline void \
atomic_set_ ## name(volatile ptype p, atype v) \
{ \
atomic_op(p, |, v, sz); \
} \
static __inline void \
atomic_set_acq_ ## name(volatile ptype p, atype v) \
{ \
atomic_op_acq(p, |, v, sz); \
} \
static __inline void \
atomic_set_rel_ ## name(volatile ptype p, atype v) \
{ \
atomic_op_rel(p, |, v, sz); \
} \
\
static __inline void \
atomic_subtract_ ## name(volatile ptype p, atype v) \
{ \
atomic_op(p, -, v, sz); \
} \
static __inline void \
atomic_subtract_acq_ ## name(volatile ptype p, atype v) \
{ \
atomic_op_acq(p, -, v, sz); \
} \
static __inline void \
atomic_subtract_rel_ ## name(volatile ptype p, atype v) \
{ \
atomic_op_rel(p, -, v, sz); \
} \
\
static __inline void \
atomic_store_ ## name(volatile ptype p, vtype v) \
{ \
atomic_store(p, v, sz); \
} \
static __inline void \
atomic_store_rel_ ## name(volatile ptype p, vtype v) \
{ \
atomic_store_rel(p, v, sz); \
}
ATOMIC_GEN(int, int *, int, int, 32);
ATOMIC_GEN(32, int *, int, int, 32);
ATOMIC_GEN(long, long *, long, long, 64);
ATOMIC_GEN(64, long *, long, long, 64);
ATOMIC_GEN(ptr, void *, void *, uintptr_t, 64);
#undef ATOMIC_GEN
#undef atomic_cas_32
#undef atomic_cas_64
#undef atomic_cas
#undef atomic_cas_acq
#undef atomic_cas_rel
#undef atomic_op
#undef atomic_op_acq
#undef atomic_op_rel
#undef atomic_load_acq
#undef atomic_store_rel
#undef atomic_load_clear
#endif /* !_MACHINE_ATOMIC_H_ */
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