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The new, cleaner, version of the atomic operations. The dummy code is…

… what you should start working with to port atomic ops.

The linux code appears to be complete and *should* be the base of all Unix and GCC based versions. The macosx and win32 versions
are currently just copies of the dummy code. I will begin working on the windows version as soon as this check in is done. I
need someone to work on the Mac OS X version.

I'm afraid that this check in will break QNX (Sorry!)
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pendletonrc committed Sep 17, 2009
1 parent 1c0e4e0 commit 7b808fcab731759c6880d554f69bc73f7fd5387f
Showing with 656 additions and 2,748 deletions.
  1. +27 −26 include/SDL_atomic.h
  2. +144 −677 src/atomic/dummy/SDL_atomic.c
  3. +168 −647 src/atomic/linux/SDL_atomic.c
  4. +144 −677 src/atomic/macosx/SDL_atomic.c
  5. +164 −697 src/atomic/win32/SDL_atomic.c
  6. +9 −24 test/testatomic.c
@@ -18,6 +18,8 @@
Sam Lantinga
Contributed by Bob Pendleton,

@@ -46,48 +48,50 @@ extern "C" {
* 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.
* 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.

/* Function prototypes */

/* 32 bit atomic operations */
* 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;

* \fn int SDL_AtomicExchange32(volatile Uint32 * ptr, Uint32 value)
* \fn void SDL_AtomicLock(SDL_SpinLock *lock);
* \brief Atomically exchange two 32 bit values.
* \brief Lock a spin lock by setting it to a none zero value.
* \return the value point to by ptr.
* \param ptr points to the value to be fetched from *ptr.
* \param value is value to be stored at *ptr.
* The current value stored at *ptr is returned and it is replaced
* with value. This function can be used to implement SDL_TestThenSet.
* \param lock points to the lock.
extern DECLSPEC Uint32 SDLCALL SDL_AtomicExchange32(volatile Uint32 * ptr, Uint32 value);
extern DECLSPEC void SDLCALL SDL_AtomicLock(SDL_SpinLock *lock);

* \fn int SDL_AtomicCompareThenSet32(volatile Uint32 * ptr, Uint32 oldvalue, Uint32 newvalue)
* \brief If *ptr == oldvalue then replace the contents of *ptr by new value.
* \fn void SDL_AtomicUnlock(SDL_SpinLock *lock);
* \return true if the newvalue was stored.
* \brief Unlock a spin lock by setting it to 0. Always returns immediately
* \param *ptr is the value to be compared and replaced.
* \param oldvalue is value to be compared to *ptr.
* \param newvalue is value to be stored at *ptr.
* \param lock points to the lock.
extern DECLSPEC SDL_bool SDLCALL SDL_AtomicCompareThenSet32(volatile Uint32 * ptr,
Uint32 oldvalue, Uint32 newvalue);
extern DECLSPEC void SDLCALL SDL_AtomicUnlock(SDL_SpinLock *lock);

/* 32 bit atomic operations */

* \fn SDL_bool SDL_AtomicTestThenSet32(volatile Uint32 * ptr);
* \brief Check to see if *ptr == 0 and set it to non-zero.
* \brief Check to see if *ptr == 0 and set it to 1.
* \return SDL_True if the value pointed to by ptr was zero and
* SDL_False if it was not zero
@@ -211,9 +215,6 @@ extern DECLSPEC Uint32 SDLCALL SDL_AtomicSubtractThenFetch32(volatile Uint32 * p
/* 64 bit atomic operations */

extern DECLSPEC Uint64 SDLCALL SDL_AtomicExchange64(volatile Uint64 * ptr, Uint64 value);
extern DECLSPEC SDL_bool SDLCALL SDL_AtomicCompareThenSet64(volatile Uint64 * ptr,
Uint64 oldvalue, Uint64 newvalue);
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);

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