3c2bc2bf26
variable and returns the previous value of the variable. Tested on: i386, alpha, sparc64, arm (cognet) Reviewed by: arch@ Submitted by: cognet (arm) MFC after: 1 week
442 lines
15 KiB
C
442 lines
15 KiB
C
/*-
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* Copyright (c) 1998 Doug Rabson
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#ifndef _MACHINE_ATOMIC_H_
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#define _MACHINE_ATOMIC_H_
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#ifndef _SYS_CDEFS_H_
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#error this file needs sys/cdefs.h as a prerequisite
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#endif
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/*
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* Various simple arithmetic on memory which is atomic in the presence
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* of interrupts and multiple processors.
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*
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* atomic_set_char(P, V) (*(u_char*)(P) |= (V))
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* atomic_clear_char(P, V) (*(u_char*)(P) &= ~(V))
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* atomic_add_char(P, V) (*(u_char*)(P) += (V))
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* atomic_subtract_char(P, V) (*(u_char*)(P) -= (V))
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*
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* atomic_set_short(P, V) (*(u_short*)(P) |= (V))
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* atomic_clear_short(P, V) (*(u_short*)(P) &= ~(V))
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* atomic_add_short(P, V) (*(u_short*)(P) += (V))
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* atomic_subtract_short(P, V) (*(u_short*)(P) -= (V))
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*
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* atomic_set_int(P, V) (*(u_int*)(P) |= (V))
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* atomic_clear_int(P, V) (*(u_int*)(P) &= ~(V))
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* atomic_add_int(P, V) (*(u_int*)(P) += (V))
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* atomic_subtract_int(P, V) (*(u_int*)(P) -= (V))
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* atomic_readandclear_int(P) (return *(u_int*)P; *(u_int*)P = 0;)
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*
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* atomic_set_long(P, V) (*(u_long*)(P) |= (V))
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* atomic_clear_long(P, V) (*(u_long*)(P) &= ~(V))
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* atomic_add_long(P, V) (*(u_long*)(P) += (V))
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* atomic_subtract_long(P, V) (*(u_long*)(P) -= (V))
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* atomic_readandclear_long(P) (return *(u_long*)P; *(u_long*)P = 0;)
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*/
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/*
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* The above functions are expanded inline in the statically-linked
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* kernel. Lock prefixes are generated if an SMP kernel is being
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* built.
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*
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* Kernel modules call real functions which are built into the kernel.
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* This allows kernel modules to be portable between UP and SMP systems.
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*/
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#if defined(KLD_MODULE) || !(defined(__GNUCLIKE_ASM) && defined(__CC_SUPPORTS___INLINE))
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#define ATOMIC_ASM(NAME, TYPE, OP, CONS, V) \
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void atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v)
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int atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src);
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int atomic_cmpset_long(volatile u_long *dst, u_long exp, u_long src);
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u_int atomic_fetchadd_int(volatile u_int *p, u_int v);
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#define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \
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u_##TYPE atomic_load_acq_##TYPE(volatile u_##TYPE *p); \
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void atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)
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#else /* !KLD_MODULE && __GNUCLIKE_ASM && __CC_SUPPORTS___INLINE */
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/*
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* For userland, assume the SMP case and use lock prefixes so that
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* the binaries will run on both types of systems.
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*/
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#if defined(SMP) || !defined(_KERNEL)
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#define MPLOCKED lock ;
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#else
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#define MPLOCKED
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#endif
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/*
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* The assembly is volatilized to demark potential before-and-after side
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* effects if an interrupt or SMP collision were to occur.
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*/
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#define ATOMIC_ASM(NAME, TYPE, OP, CONS, V) \
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static __inline void \
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atomic_##NAME##_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\
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{ \
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__asm __volatile(__XSTRING(MPLOCKED) OP \
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: "=m" (*p) \
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: CONS (V), "m" (*p)); \
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} \
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struct __hack
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/*
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* Atomic compare and set, used by the mutex functions
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*
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* if (*dst == exp) *dst = src (all 32 bit words)
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*
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* Returns 0 on failure, non-zero on success
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*/
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static __inline int
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atomic_cmpset_int(volatile u_int *dst, u_int exp, u_int src)
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{
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int res = exp;
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__asm __volatile (
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" " __XSTRING(MPLOCKED) " "
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" cmpxchgl %2,%1 ; "
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" setz %%al ; "
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" movzbl %%al,%0 ; "
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"1: "
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"# atomic_cmpset_int"
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: "+a" (res), /* 0 (result) */
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"=m" (*dst) /* 1 */
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: "r" (src), /* 2 */
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"m" (*dst) /* 3 */
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: "memory");
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return (res);
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}
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static __inline int
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atomic_cmpset_long(volatile u_long *dst, u_long exp, u_long src)
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{
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long res = exp;
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__asm __volatile (
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" " __XSTRING(MPLOCKED) " "
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" cmpxchgq %2,%1 ; "
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" setz %%al ; "
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" movzbq %%al,%0 ; "
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"1: "
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"# atomic_cmpset_long"
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: "+a" (res), /* 0 (result) */
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"=m" (*dst) /* 1 */
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: "r" (src), /* 2 */
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"m" (*dst) /* 3 */
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: "memory");
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return (res);
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}
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/*
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* Atomically add the value of v to the integer pointed to by p and return
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* the previous value of *p.
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*/
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static __inline u_int
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atomic_fetchadd_int(volatile u_int *p, u_int v)
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{
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__asm __volatile (
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" " __XSTRING(MPLOCKED) " "
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" xaddl %0, %1 ; "
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"# atomic_fetchadd_int"
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: "+r" (v), /* 0 (result) */
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"=m" (*p) /* 1 */
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: "m" (*p)); /* 2 */
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return (v);
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}
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#if defined(_KERNEL) && !defined(SMP)
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/*
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* We assume that a = b will do atomic loads and stores. However, on a
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* PentiumPro or higher, reads may pass writes, so for that case we have
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* to use a serializing instruction (i.e. with LOCK) to do the load in
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* SMP kernels. For UP kernels, however, the cache of the single processor
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* is always consistent, so we don't need any memory barriers.
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*/
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#define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \
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static __inline u_##TYPE \
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atomic_load_acq_##TYPE(volatile u_##TYPE *p) \
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{ \
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return (*p); \
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} \
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\
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static __inline void \
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atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\
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{ \
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*p = v; \
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} \
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struct __hack
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#else /* defined(SMP) */
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#define ATOMIC_STORE_LOAD(TYPE, LOP, SOP) \
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static __inline u_##TYPE \
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atomic_load_acq_##TYPE(volatile u_##TYPE *p) \
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{ \
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u_##TYPE res; \
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\
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__asm __volatile(__XSTRING(MPLOCKED) LOP \
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: "=a" (res), /* 0 (result) */\
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"=m" (*p) /* 1 */ \
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: "m" (*p) /* 2 */ \
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: "memory"); \
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\
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return (res); \
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} \
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\
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/* \
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* The XCHG instruction asserts LOCK automagically. \
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*/ \
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static __inline void \
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atomic_store_rel_##TYPE(volatile u_##TYPE *p, u_##TYPE v)\
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{ \
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__asm __volatile(SOP \
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: "=m" (*p), /* 0 */ \
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"+r" (v) /* 1 */ \
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: "m" (*p)); /* 2 */ \
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} \
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struct __hack
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#endif /* SMP */
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#endif /* KLD_MODULE || !(__GNUCLIKE_ASM && __CC_SUPPORTS___INLINE) */
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ATOMIC_ASM(set, char, "orb %b1,%0", "iq", v);
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ATOMIC_ASM(clear, char, "andb %b1,%0", "iq", ~v);
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ATOMIC_ASM(add, char, "addb %b1,%0", "iq", v);
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ATOMIC_ASM(subtract, char, "subb %b1,%0", "iq", v);
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ATOMIC_ASM(set, short, "orw %w1,%0", "ir", v);
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ATOMIC_ASM(clear, short, "andw %w1,%0", "ir", ~v);
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ATOMIC_ASM(add, short, "addw %w1,%0", "ir", v);
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ATOMIC_ASM(subtract, short, "subw %w1,%0", "ir", v);
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ATOMIC_ASM(set, int, "orl %1,%0", "ir", v);
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ATOMIC_ASM(clear, int, "andl %1,%0", "ir", ~v);
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ATOMIC_ASM(add, int, "addl %1,%0", "ir", v);
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ATOMIC_ASM(subtract, int, "subl %1,%0", "ir", v);
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ATOMIC_ASM(set, long, "orq %1,%0", "ir", v);
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ATOMIC_ASM(clear, long, "andq %1,%0", "ir", ~v);
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ATOMIC_ASM(add, long, "addq %1,%0", "ir", v);
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ATOMIC_ASM(subtract, long, "subq %1,%0", "ir", v);
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ATOMIC_STORE_LOAD(char, "cmpxchgb %b0,%1", "xchgb %b1,%0");
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ATOMIC_STORE_LOAD(short,"cmpxchgw %w0,%1", "xchgw %w1,%0");
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ATOMIC_STORE_LOAD(int, "cmpxchgl %0,%1", "xchgl %1,%0");
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ATOMIC_STORE_LOAD(long, "cmpxchgq %0,%1", "xchgq %1,%0");
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#undef ATOMIC_ASM
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#undef ATOMIC_STORE_LOAD
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#if !defined(WANT_FUNCTIONS)
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/* Read the current value and store a zero in the destination. */
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#if defined(__GNUCLIKE_ASM) && defined(__CC_SUPPORTS___INLINE)
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static __inline u_int
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atomic_readandclear_int(volatile u_int *addr)
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{
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u_int result;
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result = 0;
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__asm __volatile (
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" xchgl %1,%0 ; "
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"# atomic_readandclear_int"
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: "+r" (result), /* 0 (result) */
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"=m" (*addr) /* 1 (addr) */
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: "m" (*addr));
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return (result);
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}
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static __inline u_long
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atomic_readandclear_long(volatile u_long *addr)
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{
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u_long result;
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result = 0;
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__asm __volatile (
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" xchgq %1,%0 ; "
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"# atomic_readandclear_long"
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: "+r" (result), /* 0 (result) */
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"=m" (*addr) /* 1 (addr) */
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: "m" (*addr));
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return (result);
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}
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#else /* !(__GNUCLIKE_ASM && __CC_SUPPORTS___INLINE) */
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u_int atomic_readandclear_int(volatile u_int *);
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u_long atomic_readandclear_long(volatile u_long *);
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#endif /* __GNUCLIKE_ASM && __CC_SUPPORTS___INLINE */
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/* Acquire and release variants are identical to the normal ones. */
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#define atomic_set_acq_char atomic_set_char
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#define atomic_set_rel_char atomic_set_char
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#define atomic_clear_acq_char atomic_clear_char
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#define atomic_clear_rel_char atomic_clear_char
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#define atomic_add_acq_char atomic_add_char
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#define atomic_add_rel_char atomic_add_char
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#define atomic_subtract_acq_char atomic_subtract_char
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#define atomic_subtract_rel_char atomic_subtract_char
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#define atomic_set_acq_short atomic_set_short
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#define atomic_set_rel_short atomic_set_short
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#define atomic_clear_acq_short atomic_clear_short
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#define atomic_clear_rel_short atomic_clear_short
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#define atomic_add_acq_short atomic_add_short
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#define atomic_add_rel_short atomic_add_short
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#define atomic_subtract_acq_short atomic_subtract_short
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#define atomic_subtract_rel_short atomic_subtract_short
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#define atomic_set_acq_int atomic_set_int
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#define atomic_set_rel_int atomic_set_int
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#define atomic_clear_acq_int atomic_clear_int
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#define atomic_clear_rel_int atomic_clear_int
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#define atomic_add_acq_int atomic_add_int
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#define atomic_add_rel_int atomic_add_int
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#define atomic_subtract_acq_int atomic_subtract_int
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#define atomic_subtract_rel_int atomic_subtract_int
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#define atomic_cmpset_acq_int atomic_cmpset_int
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#define atomic_cmpset_rel_int atomic_cmpset_int
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#define atomic_set_acq_long atomic_set_long
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#define atomic_set_rel_long atomic_set_long
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#define atomic_clear_acq_long atomic_clear_long
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#define atomic_clear_rel_long atomic_clear_long
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#define atomic_add_acq_long atomic_add_long
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#define atomic_add_rel_long atomic_add_long
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#define atomic_subtract_acq_long atomic_subtract_long
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#define atomic_subtract_rel_long atomic_subtract_long
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#define atomic_cmpset_acq_long atomic_cmpset_long
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#define atomic_cmpset_rel_long atomic_cmpset_long
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/* Operations on 8-bit bytes. */
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#define atomic_set_8 atomic_set_char
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#define atomic_set_acq_8 atomic_set_acq_char
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#define atomic_set_rel_8 atomic_set_rel_char
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#define atomic_clear_8 atomic_clear_char
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#define atomic_clear_acq_8 atomic_clear_acq_char
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#define atomic_clear_rel_8 atomic_clear_rel_char
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#define atomic_add_8 atomic_add_char
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#define atomic_add_acq_8 atomic_add_acq_char
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#define atomic_add_rel_8 atomic_add_rel_char
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#define atomic_subtract_8 atomic_subtract_char
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#define atomic_subtract_acq_8 atomic_subtract_acq_char
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#define atomic_subtract_rel_8 atomic_subtract_rel_char
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#define atomic_load_acq_8 atomic_load_acq_char
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#define atomic_store_rel_8 atomic_store_rel_char
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/* Operations on 16-bit words. */
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#define atomic_set_16 atomic_set_short
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#define atomic_set_acq_16 atomic_set_acq_short
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#define atomic_set_rel_16 atomic_set_rel_short
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#define atomic_clear_16 atomic_clear_short
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#define atomic_clear_acq_16 atomic_clear_acq_short
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#define atomic_clear_rel_16 atomic_clear_rel_short
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#define atomic_add_16 atomic_add_short
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#define atomic_add_acq_16 atomic_add_acq_short
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#define atomic_add_rel_16 atomic_add_rel_short
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#define atomic_subtract_16 atomic_subtract_short
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#define atomic_subtract_acq_16 atomic_subtract_acq_short
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#define atomic_subtract_rel_16 atomic_subtract_rel_short
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#define atomic_load_acq_16 atomic_load_acq_short
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#define atomic_store_rel_16 atomic_store_rel_short
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/* Operations on 32-bit double words. */
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#define atomic_set_32 atomic_set_int
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#define atomic_set_acq_32 atomic_set_acq_int
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#define atomic_set_rel_32 atomic_set_rel_int
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#define atomic_clear_32 atomic_clear_int
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#define atomic_clear_acq_32 atomic_clear_acq_int
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#define atomic_clear_rel_32 atomic_clear_rel_int
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#define atomic_add_32 atomic_add_int
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#define atomic_add_acq_32 atomic_add_acq_int
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#define atomic_add_rel_32 atomic_add_rel_int
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#define atomic_subtract_32 atomic_subtract_int
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#define atomic_subtract_acq_32 atomic_subtract_acq_int
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#define atomic_subtract_rel_32 atomic_subtract_rel_int
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#define atomic_load_acq_32 atomic_load_acq_int
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#define atomic_store_rel_32 atomic_store_rel_int
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#define atomic_cmpset_32 atomic_cmpset_int
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#define atomic_cmpset_acq_32 atomic_cmpset_acq_int
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#define atomic_cmpset_rel_32 atomic_cmpset_rel_int
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#define atomic_readandclear_32 atomic_readandclear_int
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#define atomic_fetchadd_32 atomic_fetchadd_int
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/* Operations on 64-bit quad words. */
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#define atomic_set_64 atomic_set_long
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#define atomic_set_acq_64 atomic_set_acq_long
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#define atomic_set_rel_64 atomic_set_rel_long
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#define atomic_clear_64 atomic_clear_long
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#define atomic_clear_acq_64 atomic_clear_acq_long
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#define atomic_clear_rel_64 atomic_clear_rel_long
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#define atomic_add_64 atomic_add_long
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#define atomic_add_acq_64 atomic_add_acq_long
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#define atomic_add_rel_64 atomic_add_rel_long
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#define atomic_subtract_64 atomic_subtract_long
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#define atomic_subtract_acq_64 atomic_subtract_acq_long
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#define atomic_subtract_rel_64 atomic_subtract_rel_long
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#define atomic_load_acq_64 atomic_load_acq_long
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#define atomic_store_rel_64 atomic_store_rel_long
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#define atomic_cmpset_64 atomic_cmpset_long
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#define atomic_cmpset_acq_64 atomic_cmpset_acq_long
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#define atomic_cmpset_rel_64 atomic_cmpset_rel_long
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#define atomic_readandclear_64 atomic_readandclear_long
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/* Operations on pointers. */
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#define atomic_set_ptr atomic_set_long
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#define atomic_set_acq_ptr atomic_set_acq_long
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#define atomic_set_rel_ptr atomic_set_rel_long
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#define atomic_clear_ptr atomic_clear_long
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#define atomic_clear_acq_ptr atomic_clear_acq_long
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#define atomic_clear_rel_ptr atomic_clear_rel_long
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#define atomic_add_ptr atomic_add_long
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#define atomic_add_acq_ptr atomic_add_acq_long
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#define atomic_add_rel_ptr atomic_add_rel_long
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#define atomic_subtract_ptr atomic_subtract_long
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#define atomic_subtract_acq_ptr atomic_subtract_acq_long
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#define atomic_subtract_rel_ptr atomic_subtract_rel_long
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#define atomic_load_acq_ptr atomic_load_acq_long
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#define atomic_store_rel_ptr atomic_store_rel_long
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#define atomic_cmpset_ptr atomic_cmpset_long
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#define atomic_cmpset_acq_ptr atomic_cmpset_acq_long
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#define atomic_cmpset_rel_ptr atomic_cmpset_rel_long
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#define atomic_readandclear_ptr atomic_readandclear_long
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#endif /* !defined(WANT_FUNCTIONS) */
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#endif /* ! _MACHINE_ATOMIC_H_ */
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