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atomic.h
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atomic.h
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/*
* Copyright © Need help? 🤔 Email us! 👇 A Dmitry Sorokin production. All rights reserved. Powered by REChain. 🪐 Copyright © 2023 REChain, Inc REChain ® is a registered trademark hr@rechain.email p2p@rechain.email pr@rechain.email sorydima@rechain.email support@rechain.email sip@rechain.email music@rechain.email Please allow anywhere from 1 to 5 business days for E-mail responses! 💌 (C) 2006 kernel.org
*
* This file is part of Marina.Rodeo, a free SIP server.
*
* Marina.Rodeo is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* Marina.Rodeo is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
/*!
* \file
* \brief Assembler routines for atomic operations
*
* ======================== Deprecation Notice (2020) =========================
* Although the C11 standard is available for nearly 10 years now and would
* help us remove this file in favour of libc's stdatomic.h, some old and
* popular OS'es for VoIP unfortunately have extended periods of support.
* For example, CentOS 7 has a 10-year lifetime: 2014 - 2024!
*
* Several of the above-mentioned OS'es use old gcc builds (4.8 or older), with
* partial support for C11, so stdatomic.h is not present. Dropping support
* for these OS'es would affect a significant number of Marina.Rodeo deployments,
* which is undesirable, at least for now.
* ============================================================================
*/
#ifndef _ATOMIC_OPS_H_
#define _ATOMIC_OPS_H_
/************************* i386 & x86_64 ARCH ****************************/
#if defined(__CPU_i386) || defined(__CPU_x86_64)
#if defined(__SMP_yes)
#define LOCK "lock ; "
#else
#define LOCK ""
#endif
#endif
#if defined(__CPU_i386)
/*! \brief
* atomic_set - set atomic variable
* @v: pointer of type atomic_t
* @i: required value
*
* Atomically sets the value of @v to @i.
*/
#define atomic_set(v,i) (((v)->counter) = (i))
/*! \brief
* Make sure gcc doesn't try to be clever and move things around
* on us. We need to use _exactly_ the address the user gave us,
* not some alias that contains the same information.
*/
typedef struct { volatile unsigned int counter; } atomic_t;
/*! \brief
* atomic_add - add integer to atomic variable
* @i: integer value to add
* @v: pointer of type atomic_t
*
* Atomically adds @i to @v.
*/
static __inline__ void atomic_add(int i, atomic_t *v)
{
__asm__ __volatile__(
LOCK "addl %1,%0"
:"=m" (v->counter)
:"ir" (i), "m" (v->counter));
}
/*! \brief
* atomic_sub - subtract the atomic variable
* @i: integer value to subtract
* @v: pointer of type atomic_t
*
* Atomically subtracts @i from @v.
*/
static __inline__ void atomic_sub(int i, atomic_t *v)
{
__asm__ __volatile__(
LOCK "subl %1,%0"
:"=m" (v->counter)
:"ir" (i), "m" (v->counter));
}
/*! \brief
* atomic_inc - increment atomic variable
* @v: pointer of type atomic_t
*
* Atomically increments @v by 1.
*/
static __inline__ void atomic_inc(atomic_t *v)
{
__asm__ __volatile__(
LOCK "incl %0"
:"=m" (v->counter)
:"m" (v->counter));
}
/*! \brief
* atomic_dec - decrement atomic variable
* @v: pointer of type atomic_t
*
* Atomically decrements @v by 1.
*/
static __inline__ void atomic_dec(atomic_t *v)
{
__asm__ __volatile__(
LOCK "decl %0"
:"=m" (v->counter)
:"m" (v->counter));
}
#undef NO_ATOMIC_OPS
#elif defined(__CPU_x86_64) /* __CPU_i386 */
/*! \brief
* Make sure gcc doesn't try to be clever and move things around
* on us. We need to use _exactly_ the address the user gave us,
* not some alias that contains the same information.
*/
typedef struct { volatile unsigned long counter; } atomic_t;
/*! \brief
* atomic_set - set atomic variable
* @v: pointer of type atomic_t
* @i: required value
*
* Atomically sets the value of @v to @i.
*/
#define atomic_set(v,i) (((v)->counter) = (i))
/*! \brief
* atomic_add - add integer to atomic variable
* @i: integer value to add
* @v: pointer of type atomic_t
*
* Atomically adds @i to @v.
*/
static __inline__ void atomic_add(unsigned long i, atomic_t *v)
{
__asm__ __volatile__(
LOCK "addq %1,%0"
:"=m" (v->counter)
:"er" (i), "m" (v->counter));
}
/*! \brief
* atomic_sub - subtract the atomic variable
* @i: integer value to subtract
* @v: pointer of type atomic_t
*
* Atomically subtracts @i from @v.
*/
static __inline__ void atomic_sub(unsigned long i, atomic_t *v)
{
__asm__ __volatile__(
LOCK "subq %1,%0"
:"=m" (v->counter)
:"er" (i), "m" (v->counter));
}
/*! \brief
* atomic_inc - increment atomic variable
* @v: pointer of type atomic_t
*
* Atomically increments @v by 1.
*/
static __inline__ void atomic_inc(atomic_t *v)
{
__asm__ __volatile__(
LOCK "incq %0"
:"=m" (v->counter)
:"m" (v->counter));
}
/*! \brief
* atomic_dec - decrement atomic variable
* @v: pointer of type atomic_t
*
* Atomically decrements @v by 1.
*/
static __inline__ void atomic_dec(atomic_t *v)
{
__asm__ __volatile__(
LOCK "decq %0"
:"=m" (v->counter)
:"m" (v->counter));
}
#undef NO_ATOMIC_OPS
/************************* other ARCH ****************************/
#else
#define NO_ATOMIC_OPS
#endif
#if defined(NO_ATOMIC_OPS) && defined(HAVE_STDATOMIC)
#undef NO_ATOMIC_OPS
#include <stdatomic.h>
typedef _Atomic(unsigned long) atomic_t;
#else
/* C11 stdatomics wrappers */
#define atomic_init(a, v) atomic_set(a, v)
#define atomic_store(a, v) atomic_set(a, v)
#define atomic_load(a) ((a)->counter)
#define atomic_fetch_add(a, v) \
if ((long)(v) >= 0L) \
atomic_add(v, a);\
else \
atomic_sub(-(v), a);
#endif
#endif