/*

SDL - Simple DirectMedia Layer

Copyright (C) 1997-2009 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

*/

#include "SDL_stdinc.h"

#include "SDL_atomic.h"

#include <atomic.h>

/*

This file provides 8, 16, 32, and 64 bit atomic operations. If the

operations are provided by the native hardware and operating system

they are used. If they are not then the operations are emulated

using the SDL mutex operations.

*/

/*

First, detect whether the operations are supported and create

#defines that indicate that they do exist. The goal is to have all

the system dependent code in the top part of the file so that the

bottom can be use unchanged across all platforms.

Second, #define all the operations in each size class that are

supported. Doing this allows supported operations to be used along

side of emulated operations.

*/

/*

Emmulated version.

Assume there is no support for atomic operations. All such

operations are implemented using SDL mutex operations.

*/

#ifdef EMULATED_ATOMIC_OPERATIONS

#undef EMULATED_ATOMIC_OPERATIONS

#endif

#ifdef EMULATED_ATOMIC_OPERATIONS

#define HAVE_ALL_8_BIT_OPS

#define nativeExchange8(ptr, value) ()

#define nativeCompareThenSet8(ptr, oldvalue, newvalue) ()

#define nativeTestThenSet8(ptr) ()

#define nativeClear8(ptr) ()

#define nativeFetchThenIncrement8(ptr) ()

#define nativeFetchThenDecrement8(ptr) ()

#define nativeFetchThenAdd8(ptr, value) ()

#define nativeFetchThenSubtract8(ptr, value) ()

#define nativeIncrementThenFetch8(ptr) ()

#define nativeDecrementThenFetch8(ptr) ()

#define nativeAddThenFetch8(ptr, value) ()

#define nativeSubtractThenFetch8(ptr, value) ()

#endif

#ifdef EMULATED_ATOMIC_OPERATIONS

#define HAVE_ALL_16_BIT_OPS

#define nativeExchange16(ptr, value) ()

#define nativeCompareThenSet16(ptr, oldvalue, newvalue) ()

#define nativeTestThenSet16(ptr) ()

#define nativeClear16(ptr) ()

#define nativeFetchThenIncrement16(ptr) ()

#define nativeFetchThenDecrement16(ptr) ()

#define nativeFetchThenAdd16(ptr, value) ()

#define nativeFetchThenSubtract16(ptr, value) ()

#define nativeIncrementThenFetch16(ptr) ()

#define nativeDecrementThenFetch16(ptr) ()

#define nativeAddThenFetch16(ptr, value) ()

#define nativeSubtractThenFetch16(ptr, value) ()

#endif

#ifdef EMULATED_ATOMIC_OPERATIONS

#define HAVE_ALL_64_BIT_OPS

#define nativeExchange64(ptr, value) ()

#define nativeCompareThenSet64(ptr, oldvalue, newvalue) ()

#define nativeTestThenSet64(ptr) ()

#define nativeClear64(ptr) ()

#define nativeFetchThenIncrement64(ptr) ()

#define nativeFetchThenDecrement64(ptr) ()

#define nativeFetchThenAdd64(ptr, value) ()

#define nativeFetchThenSubtract64(ptr, value) ()

#define nativeIncrementThenFetch64(ptr) ()

#define nativeDecrementThenFetch64(ptr) ()

#define nativeAddThenFetch64(ptr, value) ()

#define nativeSubtractThenFetch64(ptr, value) ()

#endif

/*

If any of the operations are not provided then we must emulate some of

them.

*/

#if !defined(HAVE_ALL_8_BIT_OPS) || !defined(HAVE_ALL_16_BIT_OPS) || !defined(HAVE_ALL_64_BIT_OPS)

#include "SDL_mutex.h"

#include "SDL_error.h"

static SDL_mutex * lock = NULL;

static __inline__ void

privateWaitLock()

{

if(NULL == lock)

{

lock = SDL_CreateMutex();

if (NULL == lock)

{

SDL_SetError("SDL_atomic.c: can't create a mutex");

return;

}

}

if (-1 == SDL_LockMutex(lock))

{

SDL_SetError("SDL_atomic.c: can't lock mutex");

}

}

static __inline__ void

privateUnlock()

{

if (-1 == SDL_UnlockMutex(lock))

{

SDL_SetError("SDL_atomic.c: can't unlock mutex");

}

}

#endif

/* 8 bit atomic operations */

Uint8

SDL_AtomicExchange8(volatile Uint8 * ptr, Uint8 value)

{

#ifdef nativeExchange8

return nativeExchange8(ptr, value);

#else

Uint8 tmp = 0;

privateWaitLock();

tmp = *ptr;

*ptr = value;

privateUnlock();

return tmp;

#endif

}

SDL_bool

SDL_AtomicCompareThenSet8(volatile Uint8 * ptr, Uint8 oldvalue, Uint8 newvalue)

{

#ifdef nativeCompareThenSet8

return (SDL_bool)nativeCompareThenSet8(ptr, oldvalue, newvalue);

#else

SDL_bool result = SDL_FALSE;

privateWaitLock();

result = (*ptr == oldvalue);

if (result)

{

*ptr = newvalue;

}

privateUnlock();

return result;

#endif

}

SDL_bool

SDL_AtomicTestThenSet8(volatile Uint8 * ptr)

{

#ifdef nativeTestThenSet8

return (SDL_bool)nativeTestThenSet8(ptr);

#else

SDL_bool result = SDL_FALSE;

privateWaitLock();

result = (*ptr == 0);

if (result)

{

*ptr = 1;

}

privateUnlock();

return result;

#endif

}

void

SDL_AtomicClear8(volatile Uint8 * ptr)

{

#ifdef nativeClear8

nativeClear8(ptr);

#else

privateWaitLock();

*ptr = 0;

privateUnlock();

return;

#endif

}

Uint8

SDL_AtomicFetchThenIncrement8(volatile Uint8 * ptr)

{

#ifdef nativeFetchThenIncrement8

return nativeFetchThenIncrement8(ptr);

#else

Uint8 tmp = 0;

privateWaitLock();

tmp = *ptr;

(*ptr)+= 1;

privateUnlock();

return tmp;

#endif

}

Uint8

SDL_AtomicFetchThenDecrement8(volatile Uint8 * ptr)

{

#ifdef nativeFetchThenDecrement8

return nativeFetchThenDecrement8(ptr);

#else

Uint8 tmp = 0;

privateWaitLock();

tmp = *ptr;

(*ptr) -= 1;

privateUnlock();

return tmp;

#endif

}

Uint8

SDL_AtomicFetchThenAdd8(volatile Uint8 * ptr, Uint8 value)

{

#ifdef nativeFetchThenAdd8

return nativeFetchThenAdd8(ptr, value);

#else

Uint8 tmp = 0;

privateWaitLock();

tmp = *ptr;

(*ptr)+= value;

privateUnlock();

return tmp;

#endif

}

Uint8

SDL_AtomicFetchThenSubtract8(volatile Uint8 * ptr, Uint8 value)

{

#ifdef nativeFetchThenSubtract8

return nativeFetchThenSubtract8(ptr, value);

#else

Uint8 tmp = 0;

privateWaitLock();

tmp = *ptr;

(*ptr)-= value;

privateUnlock();

return tmp;

#endif

}

Uint8

SDL_AtomicIncrementThenFetch8(volatile Uint8 * ptr)

{

#ifdef nativeIncrementThenFetch8

return nativeIncrementThenFetch8(ptr);

#else

Uint8 tmp = 0;

privateWaitLock();

(*ptr)+= 1;

tmp = *ptr;

privateUnlock();

return tmp;

#endif

}

Uint8

SDL_AtomicDecrementThenFetch8(volatile Uint8 * ptr)

{

#ifdef nativeDecrementThenFetch8

return nativeDecrementThenFetch8(ptr);

#else

Uint8 tmp = 0;

privateWaitLock();

(*ptr)-= 1;

tmp = *ptr;

privateUnlock();

return tmp;

#endif

}

Uint8

SDL_AtomicAddThenFetch8(volatile Uint8 * ptr, Uint8 value)

{

#ifdef nativeAddThenFetch8

return nativeAddThenFetch8(ptr, value);

#else

Uint8 tmp = 0;

privateWaitLock();

(*ptr)+= value;

tmp = *ptr;

privateUnlock();

return tmp;

#endif

}

Uint8

SDL_AtomicSubtractThenFetch8(volatile Uint8 * ptr, Uint8 value)

{

#ifdef nativeSubtractThenFetch8

return nativeSubtractThenFetch8(ptr, value);

#else

Uint8 tmp = 0;

privateWaitLock();

(*ptr)-= value;

tmp = *ptr;

privateUnlock();

return tmp;

#endif

}

/* 16 bit atomic operations */

Uint16

SDL_AtomicExchange16(volatile Uint16 * ptr, Uint16 value)

{

#ifdef nativeExchange16

return nativeExchange16(ptr, value);

#else

Uint16 tmp = 0;

privateWaitLock();

tmp = *ptr;

*ptr = value;

privateUnlock();

return tmp;

#endif

}

SDL_bool

SDL_AtomicCompareThenSet16(volatile Uint16 * ptr, Uint16 oldvalue, Uint16 newvalue)

{

#ifdef nativeCompareThenSet16

return (SDL_bool)nativeCompareThenSet16(ptr, oldvalue, newvalue);

#else

SDL_bool result = SDL_FALSE;

privateWaitLock();

result = (*ptr == oldvalue);

if (result)

{

*ptr = newvalue;

}

privateUnlock();

return result;

#endif

}

SDL_bool

SDL_AtomicTestThenSet16(volatile Uint16 * ptr)

{

#ifdef nativeTestThenSet16

return (SDL_bool)nativeTestThenSet16(ptr);

#else

SDL_bool result = SDL_FALSE;

privateWaitLock();

result = (*ptr == 0);

if (result)

{

*ptr = 1;

}

privateUnlock();

return result;

#endif

}

void

SDL_AtomicClear16(volatile Uint16 * ptr)

{

#ifdef nativeClear16

nativeClear16(ptr);

#else

privateWaitLock();

*ptr = 0;

privateUnlock();

return;

#endif

}

Uint16

SDL_AtomicFetchThenIncrement16(volatile Uint16 * ptr)

{

#ifdef nativeFetchThenIncrement16

return nativeFetchThenIncrement16(ptr);

#else

Uint16 tmp = 0;

privateWaitLock();

tmp = *ptr;

(*ptr)+= 1;

privateUnlock();

return tmp;

#endif

}

Uint16

SDL_AtomicFetchThenDecrement16(volatile Uint16 * ptr)

{

#ifdef nativeFetchThenDecrement16

return nativeFetchThenDecrement16(ptr);

#else

Uint16 tmp = 0;

privateWaitLock();

tmp = *ptr;

(*ptr) -= 1;

privateUnlock();

return tmp;

#endif

}

Uint16

SDL_AtomicFetchThenAdd16(volatile Uint16 * ptr, Uint16 value)

{

#ifdef nativeFetchThenAdd16

return nativeFetchThenAdd16(ptr, value);

#else

Uint16 tmp = 0;

privateWaitLock();

tmp = *ptr;

(*ptr)+= value;

privateUnlock();

return tmp;

#endif

}

Uint16

SDL_AtomicFetchThenSubtract16(volatile Uint16 * ptr, Uint16 value)

{

#ifdef nativeFetchThenSubtract16

return nativeFetchThenSubtract16(ptr, value);

#else

Uint16 tmp = 0;

privateWaitLock();

tmp = *ptr;

(*ptr)-= value;

privateUnlock();

return tmp;

#endif

}

Uint16

SDL_AtomicIncrementThenFetch16(volatile Uint16 * ptr)

{

#ifdef nativeIncrementThenFetch16

return nativeIncrementThenFetch16(ptr);

#else

Uint16 tmp = 0;

privateWaitLock();

(*ptr)+= 1;

tmp = *ptr;

privateUnlock();

return tmp;

#endif

}

Uint16

SDL_AtomicDecrementThenFetch16(volatile Uint16 * ptr)

{

#ifdef nativeDecrementThenFetch16

return nativeDecrementThenFetch16(ptr);

#else

Uint16 tmp = 0;

privateWaitLock();

(*ptr)-= 1;

tmp = *ptr;

privateUnlock();

return tmp;

#endif

}

Uint16

SDL_AtomicAddThenFetch16(volatile Uint16 * ptr, Uint16 value)

{

#ifdef nativeAddThenFetch16

return nativeAddThenFetch16(ptr, value);

#else

Uint16 tmp = 0;

privateWaitLock();

(*ptr)+= value;

tmp = *ptr;

privateUnlock();

return tmp;

#endif

}

Uint16

SDL_AtomicSubtractThenFetch16(volatile Uint16 * ptr, Uint16 value)

{

#ifdef nativeSubtractThenFetch16

return nativeSubtractThenFetch16(ptr, value);

#else

Uint16 tmp = 0;

privateWaitLock();

(*ptr)-= value;

tmp = *ptr;

privateUnlock();

return tmp;

#endif

}

/* 64 bit atomic operations */

#ifdef SDL_HAS_64BIT_TYPE

Uint64

SDL_AtomicExchange64(volatile Uint64 * ptr, Uint64 value)

{

#ifdef nativeExchange64

return nativeExchange64(ptr, value);

#else

Uint64 tmp = 0;

privateWaitLock();

tmp = *ptr;

*ptr = value;

privateUnlock();

return tmp;

#endif

}

SDL_bool

SDL_AtomicCompareThenSet64(volatile Uint64 * ptr, Uint64 oldvalue, Uint64 newvalue)

{

#ifdef nativeCompareThenSet64

return (SDL_bool)nativeCompareThenSet64(ptr, oldvalue, newvalue);

#else

SDL_bool result = SDL_FALSE;

privateWaitLock();

result = (*ptr == oldvalue);

if (result)

{

*ptr = newvalue;

}

privateUnlock();

return result;

#endif

}

SDL_bool

SDL_AtomicTestThenSet64(volatile Uint64 * ptr)

{

#ifdef nativeTestThenSet64

return (SDL_bool)nativeTestThenSet64(ptr);

#else

SDL_bool result = SDL_FALSE;

privateWaitLock();

result = (*ptr == 0);

if (result)

{

*ptr = 1;

}

privateUnlock();

return result;

#endif

}

void

SDL_AtomicClear64(volatile Uint64 * ptr)

{

#ifdef nativeClear64

nativeClear64(ptr);

#else

privateWaitLock();

*ptr = 0;

privateUnlock();

return;

#endif

}

Uint64

SDL_AtomicFetchThenIncrement64(volatile Uint64 * ptr)

{

#ifdef nativeFetchThenIncrement64

return nativeFetchThenIncrement64(ptr);

#else

Uint64 tmp = 0;

privateWaitLock();

tmp = *ptr;

(*ptr)+= 1;

privateUnlock();

return tmp;

#endif

}

Uint64

SDL_AtomicFetchThenDecrement64(volatile Uint64 * ptr)

{

#ifdef nativeFetchThenDecrement64

return nativeFetchThenDecrement64(ptr);

#else

Uint64 tmp = 0;

privateWaitLock();

tmp = *ptr;

(*ptr) -= 1;

privateUnlock();

return tmp;

#endif

}

Uint64

SDL_AtomicFetchThenAdd64(volatile Uint64 * ptr, Uint64 value)

{

#ifdef nativeFetchThenAdd64

return nativeFetchThenAdd64(ptr, value);

#else

Uint64 tmp = 0;

privateWaitLock();

tmp = *ptr;

(*ptr)+= value;

privateUnlock();

return tmp;

#endif

}

Uint64

SDL_AtomicFetchThenSubtract64(volatile Uint64 * ptr, Uint64 value)

{

#ifdef nativeFetchThenSubtract64

return nativeFetchThenSubtract64(ptr, value);

#else

Uint64 tmp = 0;

privateWaitLock();

tmp = *ptr;

(*ptr)-= value;

privateUnlock();

return tmp;

#endif

}

Uint64

SDL_AtomicIncrementThenFetch64(volatile Uint64 * ptr)

{

#ifdef nativeIncrementThenFetch64

return nativeIncrementThenFetch64(ptr);

#else

Uint64 tmp = 0;

privateWaitLock();

(*ptr)+= 1;

tmp = *ptr;

privateUnlock();

return tmp;

#endif

}

Uint64

SDL_AtomicDecrementThenFetch64(volatile Uint64 * ptr)

{

#ifdef nativeDecrementThenFetch64

return nativeDecrementThenFetch64(ptr);

#else

Uint64 tmp = 0;

privateWaitLock();

(*ptr)-= 1;

tmp = *ptr;

privateUnlock();

return tmp;

#endif

}

Uint64

SDL_AtomicAddThenFetch64(volatile Uint64 * ptr, Uint64 value)

{

#ifdef nativeAddThenFetch64

return nativeAddThenFetch64(ptr, value);

#else

Uint64 tmp = 0;

privateWaitLock();

(*ptr)+= value;

tmp = *ptr;

privateUnlock();

return tmp;

#endif

}

Uint64

SDL_AtomicSubtractThenFetch64(volatile Uint64 * ptr, Uint64 value)

{

#ifdef nativeSubtractThenFetch64

return nativeSubtractThenFetch64(ptr, value);

#else

Uint64 tmp = 0;

privateWaitLock();

(*ptr)-= value;

tmp = *ptr;

privateUnlock();

return tmp;

#endif

}

#endif

/* QNX native 32 bit atomic operations */

Uint32

SDL_AtomicExchange32(volatile Uint32 * ptr, Uint32 value)

{

Uint32 tmp = 0;

privateWaitLock();

tmp = *ptr;

*ptr = value;

privateUnlock();

return tmp;

}

SDL_bool

SDL_AtomicCompareThenSet32(volatile Uint32 * ptr, Uint32 oldvalue, Uint32 newvalue)

{

SDL_bool result = SDL_FALSE;

privateWaitLock();

result = (*ptr == oldvalue);

if (result)

{

*ptr = newvalue;

}

privateUnlock();

return result;

}

SDL_bool

SDL_AtomicTestThenSet32(volatile Uint32 * ptr)

{

SDL_bool result = SDL_FALSE;

privateWaitLock();

result = (*ptr == 0);

if (result)

{

*ptr = 1;

}

privateUnlock();

return result;

}

void

SDL_AtomicClear32(volatile Uint32 * ptr)

{

atomic_clr(ptr, 0xFFFFFFFF);

}

Uint32

SDL_AtomicFetchThenIncrement32(volatile Uint32 * ptr)

{

return atomic_add_value(ptr, 0x00000001);

}

Uint32

SDL_AtomicFetchThenDecrement32(volatile Uint32 * ptr)

{

return atomic_sub_value(ptr, 0x00000001);

}

Uint32

SDL_AtomicFetchThenAdd32(volatile Uint32 * ptr, Uint32 value)

{

return atomic_add_value(ptr, value);

}

Uint32

SDL_AtomicFetchThenSubtract32(volatile Uint32 * ptr, Uint32 value)

{

return atomic_sub_value(ptr, value);

}

Uint32

SDL_AtomicIncrementThenFetch32(volatile Uint32 * ptr)

{

atomic_add(ptr, 0x00000001);

return atomic_add_value(ptr, 0x00000000);

}

Uint32

SDL_AtomicDecrementThenFetch32(volatile Uint32 * ptr)

{

atomic_sub(ptr, 0x00000001);

return atomic_sub_value(ptr, 0x00000000);

}

Uint32

SDL_AtomicAddThenFetch32(volatile Uint32 * ptr, Uint32 value)

{

atomic_add(ptr, value);

return atomic_add_value(ptr, 0x00000000);

}

Uint32

SDL_AtomicSubtractThenFetch32(volatile Uint32 * ptr, Uint32 value)

{

atomic_sub(ptr, value);

return atomic_sub_value(ptr, 0x00000000);

}