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SDL_atomic.h
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/*
SDL - Simple DirectMedia Layer
Copyright (C) 1997-2006 Sam Lantinga
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
This library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
Sam Lantinga
slouken@libsdl.org
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Contributed by Bob Pendleton, bob@pendleton.com
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*/
/**
* \file SDL_atomic.h
*
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* Atomic operations.
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*/
#ifndef _SDL_atomic_h_
#define _SDL_atomic_h_
#include "SDL_stdinc.h"
#include "SDL_platform.h"
#include "begin_code.h"
/* Set up for C function definitions, even when using C++ */
#ifdef __cplusplus
/* *INDENT-OFF* */
extern "C" {
/* *INDENT-ON* */
#endif
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* These operations may, or may not, actually be implemented using
* processor specific atomic operations. When possible they are
* implemented as true processor specific atomic operations. When that
* is not possible the are implemented using locks that *do* use the
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* available atomic operations.
*
* At the very minimum spin locks must be implemented. Without spin
* locks it is not possible (AFAICT) to emulate the rest of the atomic
* operations.
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/* Function prototypes */
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/**
* SDL AtomicLock.
*
* The spin lock functions and type are required and can not be
* emulated because they are used in the emulation code.
*/
typedef volatile Uint32 SDL_SpinLock;
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* \fn void SDL_AtomicLock(SDL_SpinLock *lock);
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* \brief Lock a spin lock by setting it to a none zero value.
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* \param lock points to the lock.
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extern DECLSPEC void SDLCALL SDL_AtomicLock(SDL_SpinLock *lock);
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* \fn void SDL_AtomicUnlock(SDL_SpinLock *lock);
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* \brief Unlock a spin lock by setting it to 0. Always returns immediately
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* \param lock points to the lock.
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extern DECLSPEC void SDLCALL SDL_AtomicUnlock(SDL_SpinLock *lock);
/* 32 bit atomic operations */
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* \fn SDL_bool SDL_AtomicTestThenSet32(volatile Uint32 * ptr);
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* \brief Check to see if *ptr == 0 and set it to 1.
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*
* \return SDL_True if the value pointed to by ptr was zero and
* SDL_False if it was not zero
*
* \param ptr points to the value to be tested and set.
*
*/
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extern DECLSPEC SDL_bool SDLCALL SDL_AtomicTestThenSet32(volatile Uint32 * ptr);
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* \fn void SDL_AtomicClear32(volatile Uint32 * ptr);
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*
* \brief set the value pointed to by ptr to be zero.
*
* \param ptr address of the value to be set to zero
*
*/
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extern DECLSPEC void SDLCALL SDL_AtomicClear32(volatile Uint32 * ptr);
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* \fn Uint32 SDL_AtomicFetchThenIncrement32(volatile Uint32 * ptr);
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*
* \brief fetch the current value of *ptr and then increment that
* value in place.
*
* \return the value before it was incremented.
*
* \param ptr address of the value to fetch and increment
*
*/
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extern DECLSPEC Uint32 SDLCALL SDL_AtomicFetchThenIncrement32(volatile Uint32 * ptr);
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* \fn Uint32 SDL_AtomicFetchThenDecrement32(volatile Uint32 * ptr);
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*
* \brief fetch *ptr and then decrement the value in place.
*
* \return the value before it was decremented.
*
* \param ptr address of the value to fetch and drement
*
*/
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extern DECLSPEC Uint32 SDLCALL SDL_AtomicFetchThenDecrement32(volatile Uint32 * ptr);
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* \fn Uint32 SDL_AtomicFetchThenAdd32(volatile Uint32 * ptr, Uint32 value);
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*
* \brief fetch the current value at ptr and then add value to *ptr.
*
* \return *ptr before the addition took place.
*
* \param ptr the address of data we are changing.
* \param value the value to add to *ptr.
*
*/
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extern DECLSPEC Uint32 SDLCALL SDL_AtomicFetchThenAdd32(volatile Uint32 * ptr, Uint32 value);
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* \fn Uint32 SDL_AtomicFetchThenSubtract32(volatile Uint32 * ptr, Uint32 value);
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*
* \brief Fetch *ptr and then subtract value from it.
*
* \return *ptr before the subtraction took place.
*
* \param ptr the address of the data being changed.
* \param value the value to subtract from *ptr.
*
*/
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extern DECLSPEC Uint32 SDLCALL SDL_AtomicFetchThenSubtract32(volatile Uint32 * ptr, Uint32 value);
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* \fn Uint32 SDL_AtomicIncrementThenFetch32(volatile Uint32 * ptr);
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*
* \brief Add one to the data pointed to by ptr and return that value.
*
* \return the incremented value.
*
* \param ptr address of the data to increment.
*
*/
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extern DECLSPEC Uint32 SDLCALL SDL_AtomicIncrementThenFetch32(volatile Uint32 * ptr);
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* \fn Uint32 SDL_AtomicDecrementThenFetch32(volatile Uint32 * ptr);
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*
* \brief Subtract one from data pointed to by ptr and return the new value.
*
* \return The decremented value.
*
* \param ptr The address of the data to decrement.
*
*/
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extern DECLSPEC Uint32 SDLCALL SDL_AtomicDecrementThenFetch32(volatile Uint32 * ptr);
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* \fn Uint32 SDL_AtomicAddThenFetch32(volatile Uint32 * ptr, Uint32 value);
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*
* \brief Add value to the data pointed to by ptr and return result.
*
* \return The sum of *ptr and value.
*
* \param ptr The address of the data to be modified.
* \param value The value to be added.
*
*/
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extern DECLSPEC Uint32 SDLCALL SDL_AtomicAddThenFetch32(volatile Uint32 * ptr, Uint32 value);
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* \fn Uint32 SDL_AtomicSubtractThenFetch32(volatile Uint32 * ptr, Uint32 value);
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*
* \brief Subtract value from the data pointed to by ptr and return the result.
*
* \return the difference between *ptr and value.
*
* \param ptr The address of the data to be modified.
* \param value The value to be subtracted.
*
*/
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extern DECLSPEC Uint32 SDLCALL SDL_AtomicSubtractThenFetch32(volatile Uint32 * ptr, Uint32 value);
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/* 64 bit atomic operations */
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#ifdef SDL_HAS_64BIT_TYPE
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extern DECLSPEC SDL_bool SDLCALL SDL_AtomicTestThenSet64(volatile Uint64 * ptr);
extern DECLSPEC void SDLCALL SDL_AtomicClear64(volatile Uint64 * ptr);
extern DECLSPEC Uint64 SDLCALL SDL_AtomicFetchThenIncrement64(volatile Uint64 * ptr);
extern DECLSPEC Uint64 SDLCALL SDL_AtomicFetchThenDecrement64(volatile Uint64 * ptr);
extern DECLSPEC Uint64 SDLCALL SDL_AtomicFetchThenAdd64(volatile Uint64 * ptr, Uint64 value);
extern DECLSPEC Uint64 SDLCALL SDL_AtomicFetchThenSubtract64(volatile Uint64 * ptr, Uint64 value);
extern DECLSPEC Uint64 SDLCALL SDL_AtomicIncrementThenFetch64(volatile Uint64 * ptr);
extern DECLSPEC Uint64 SDLCALL SDL_AtomicDecrementThenFetch64(volatile Uint64 * ptr);
extern DECLSPEC Uint64 SDLCALL SDL_AtomicAddThenFetch64(volatile Uint64 * ptr, Uint64 value);
extern DECLSPEC Uint64 SDLCALL SDL_AtomicSubtractThenFetch64(volatile Uint64 * ptr, Uint64 value);
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#endif /* SDL_HAS_64BIT_TYPE */
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/* Ends C function definitions when using C++ */
#ifdef __cplusplus
/* *INDENT-OFF* */
}
/* *INDENT-ON* */
#endif
#include "close_code.h"
#endif /* _SDL_atomic_h_ */
/* vi: set ts=4 sw=4 expandtab: */