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Provide atomic load and store functions for int and long.  FreeBSD
also uses these names.  This implements a complete interface for
atomic operations, such functions can be used for every access.
They provide compiler barriers, but no CPU memory barriers.  This
is consistent with our other atomic operations.
OK mvs@ visa@

.\" $OpenBSD: atomic_load_int.9,v 1.1 2022/03/10 14:12:40 bluhm Exp $
.\"
.\" Copyright (c) 2014 David Gwynne <dlg@openbsd.org>
.\" Copyright (c) 2022 Alexander Bluhm <bluhm@openbsd.org>
.\" All rights reserved.
.\"
.\" Permission to use, copy, modify, and 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.
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.\" THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
.\" WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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.\" WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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.\"
.Dd $Mdocdate: March 10 2022 $
.Dt ATOMIC_LOAD_INT 9
.Os
.Sh NAME
.Nm atomic_load_int ,
.Nm atomic_load_long ,
.Nm atomic_store_long ,
.Nm atomic_store_int
.Nd atomic read and write memory operations
.Sh SYNOPSIS
.In sys/atomic.h
.Ft unsigned int
.Fn atomic_load_int "volatile unsigned int *p"
.Ft unsigned long
.Fn atomic_load_long "volatile unsigned long *p"
.Ft void
.Fn atomic_store_int "volatile unsigned int *p" "unsigned int v"
.Ft void
.Fn atomic_store_long "volatile unsigned long *p" "unsigned long v"
.Sh DESCRIPTION
The atomic_load and atomic_store set of functions provide an interface
for atomically performing read or write memory operations with
respect to interrupts and multiple processors in the system.
.Pp
The atomic_store functions change the value referenced by the pointer
.Fa p
to the value
.Fa v .
.Sh CONTEXT
.Fn atomic_load_int ,
.Fn atomic_load_long ,
.Fn atomic_store_int ,
and
.Fn atomic_store_long
can all be called during autoconf, from process context, or from
interrupt context.
.Sh RETURN VALUES
.Nm atomic_load_int
and
.Nm atomic_load_long
return the value at
.Fa p .
.Sh SEE ALSO
.Xr atomic_add_int 9 ,
.Xr atomic_add_long 9 ,
.Xr atomic_sub_int 9 ,
.Xr atomic_sub_long 9
.Sh HISTORY
The atomic_load and atomic_store functions first appeared in
.Ox 7.1 .