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I've made so many changes I don't dare continue until I check the cur…
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…rent stuff in.

/test/testatomic.c performs absolutely basic tests to show that the function work as expected. Need a second test to do more detailed tests.

/include/SDL_atomic.h provides declarations for all included functions.

/src/atomic/linux/SDL_atomic.c provided all the functions. On a generic built the 64 bit functions work, but they are emulated. On a build for -march=pentium and above the 64 bit functions use native instructions
/src/atomic/dummy/SDL_atomic.c emulates all the operations using SDL_mutex.h.
/src/atomic/win32/SDL_atomic.c is a copy of dummy
/src/atomic/macosx/SDL_atomic.s is a copy of dummy

These versions of SDL_atomic.c provide a frame work for building the library with a mixture of native and emulated functions. This allows the whole library to be provided on all platforms. (I hope.)
I hope this fits with the SDL philosophy of either providing a common subset or emulating when the platform is missing a feature.

I have not added dummy, macosx, or win32 to the build. They are there as place holders for future work.

I have modified congifure.in to compile sources in /src/atomic/linux. (The SDL configure.in file is an amazing piece of work and I hope I didn't mess it up. :-)
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@pendletonrc
pendletonrc committed Jun 29, 2009
1 parent 4283990 commit 0de4bbe
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Showing 6 changed files with 3,774 additions and 158 deletions.
101 changes: 40 additions & 61 deletions include/SDL_atomic.h
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Expand Up @@ -29,7 +29,6 @@
#ifndef _SDL_atomic_h_
#define _SDL_atomic_h_


#include "SDL_stdinc.h"
#include "SDL_platform.h"

Expand All @@ -42,71 +41,50 @@ extern "C" {
/* *INDENT-ON* */
#endif

/* *INDENT-OFF* */
/**
* \def SDL_AtomicBusyWait32 (ptr)
*
* \brief Implements a simple busy wait for use with
* SDL_AtomicTestThenSet and SDL_AtomicClear.
*
* Note: This can be an infinite loop.
*
* 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
* available atomic operations. In rare cases they may be implemented
* using SDL's mutex fuctions.
*/
#define SDL_AtomicBusyWait32(ptr) \
{ \
while (!SDL_AtomicTestThenSet32(ptr) \
{ \
}; \
};

/**
* \def SDL_AtomicWait32(ptr)
*
* \brief A safer way to wait for a test-then-set lock to be cleared.
*
* This assumes that the SDL_Sleep(0) call acts as a thread_yeild
* operation.
*
*/
#define SDL_AtomicWait32(ptr) \
{ \
while (!SDL_AtomicTestThenSet32(ptr) \
{ \
SDL_Sleep(0); \
}; \
};
/* Function prototypes */

/**
* \def SDL_AtomicBusyWait64(ptr)
*
* \brief 64 bit version of busy wait
*
* \sa SDL_AtomicBusyWait32
*/
#define SDL_AtomicBusyWait64(ptr) \
{ \
while (!SDL_AtomicTestThenSet64(ptr) \
{ \
}; \
};
/* 8 bit atomic operations */

/**
* \def SDL_AtomicWait64(ptr)
*
* \brief 64 bit version of SDL_AtomicWait32
*
* \sa SDL_AtomicWait32
*/
#define SDL_AtomicWait64(ptr) \
{ \
while (!SDL_AtomicTestThenSet64(ptr) \
{ \
SDL_Sleep(0); \
}; \
};
/* *INDENT-ON* */
extern DECLSPEC Uint8 SDLCALL SDL_AtomicExchange8(Uint8 * ptr, Uint8 value);
extern DECLSPEC SDL_bool SDLCALL SDL_AtomicCompareThenSet8(Uint8 * ptr,
Uint8 oldvalue, Uint8 newvalue);
extern DECLSPEC SDL_bool SDLCALL SDL_AtomicTestThenSet8(Uint8 * ptr);
extern DECLSPEC void SDLCALL SDL_AtomicClear8(Uint8 * ptr);
extern DECLSPEC Uint8 SDLCALL SDL_AtomicFetchThenIncrement8(Uint8 * ptr);
extern DECLSPEC Uint8 SDLCALL SDL_AtomicFetchThenDecrement8(Uint8 * ptr);
extern DECLSPEC Uint8 SDLCALL SDL_AtomicFetchThenAdd8(Uint8 * ptr, Uint8 value);
extern DECLSPEC Uint8 SDLCALL SDL_AtomicFetchThenSubtract8(Uint8 * ptr, Uint8 value);
extern DECLSPEC Uint8 SDLCALL SDL_AtomicIncrementThenFetch8(Uint8 * ptr);
extern DECLSPEC Uint8 SDLCALL SDL_AtomicDecrementThenFetch8(Uint8 * ptr);
extern DECLSPEC Uint8 SDLCALL SDL_AtomicAddThenFetch8(Uint8 * ptr, Uint8 value);
extern DECLSPEC Uint8 SDLCALL SDL_AtomicSubtractThenFetch8(Uint8 * ptr, Uint8 value);

/* Function prototypes */
/* 16 bit atomic operations */

extern DECLSPEC Uint16 SDLCALL SDL_AtomicExchange16(Uint16 * ptr, Uint16 value);
extern DECLSPEC SDL_bool SDLCALL SDL_AtomicCompareThenSet16(Uint16 * ptr,
Uint16 oldvalue, Uint16 newvalue);
extern DECLSPEC SDL_bool SDLCALL SDL_AtomicTestThenSet16(Uint16 * ptr);
extern DECLSPEC void SDLCALL SDL_AtomicClear16(Uint16 * ptr);
extern DECLSPEC Uint16 SDLCALL SDL_AtomicFetchThenIncrement16(Uint16 * ptr);
extern DECLSPEC Uint16 SDLCALL SDL_AtomicFetchThenDecrement16(Uint16 * ptr);
extern DECLSPEC Uint16 SDLCALL SDL_AtomicFetchThenAdd16(Uint16 * ptr, Uint16 value);
extern DECLSPEC Uint16 SDLCALL SDL_AtomicFetchThenSubtract16(Uint16 * ptr, Uint16 value);
extern DECLSPEC Uint16 SDLCALL SDL_AtomicIncrementThenFetch16(Uint16 * ptr);
extern DECLSPEC Uint16 SDLCALL SDL_AtomicDecrementThenFetch16(Uint16 * ptr);
extern DECLSPEC Uint16 SDLCALL SDL_AtomicAddThenFetch16(Uint16 * ptr, Uint16 value);
extern DECLSPEC Uint16 SDLCALL SDL_AtomicSubtractThenFetch16(Uint16 * ptr, Uint16 value);

/* 32 bit atomic operations */

/**
* \fn int SDL_AtomicExchange32(Uint32 * ptr, Uint32 value)
Expand Down Expand Up @@ -252,6 +230,7 @@ extern DECLSPEC Uint32 SDLCALL SDL_AtomicAddThenFetch32(Uint32 * ptr, Uint32 val
*/
extern DECLSPEC Uint32 SDLCALL SDL_AtomicSubtractThenFetch32(Uint32 * ptr, Uint32 value);

/* 64 bit atomic operations */
#ifdef SDL_HAS_64BIT_TYPE

extern DECLSPEC Uint64 SDLCALL SDL_AtomicExchange64(Uint64 * ptr, Uint64 value);
Expand All @@ -267,7 +246,7 @@ extern DECLSPEC Uint64 SDLCALL SDL_AtomicIncrementThenFetch64(Uint64 * ptr);
extern DECLSPEC Uint64 SDLCALL SDL_AtomicDecrementThenFetch64(Uint64 * ptr);
extern DECLSPEC Uint64 SDLCALL SDL_AtomicAddThenFetch64(Uint64 * ptr, Uint64 value);
extern DECLSPEC Uint64 SDLCALL SDL_AtomicSubtractThenFetch64(Uint64 * ptr, Uint64 value);
#endif
#endif /* SDL_HAS_64BIT_TYPE */

/* Ends C function definitions when using C++ */
#ifdef __cplusplus
Expand Down

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