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Added native atomic operations for Windows, Mac OS X, and gcc compiler intrinsics.

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Changed the CAS return value to bool, so it's efficient with OSAtomicCompareAndSwap32Barrier()
Added an atomic test adapted from code by Michael Davidsaver
This commit is contained in:
Sam Lantinga 2011-01-16 15:16:39 -08:00
parent 1bc8fe69ce
commit b0e0f61c7e
8 changed files with 301 additions and 62 deletions
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61
src/atomic/SDL_atomic.c
View file

@ -23,6 +23,12 @@
#include "SDL_atomic.h"
/* Note that we undefine the atomic operations here, in case they are
defined as compiler intrinsics while building SDL but the library user
doesn't have that compiler. That way we always have a working set of
atomic operations built into the library.
*/
/*
If any of the operations are not provided then we must emulate some
of them. That means we need a nice implementation of spin locks
@ -51,20 +57,20 @@ static SDL_SpinLock locks[32];
static __inline__ void
enterLock(void *a)
{
uintptr_t index = ((((uintptr_t)a) >> 3) & 0x1f);
uintptr_t index = ((((uintptr_t)a) >> 3) & 0x1f);
SDL_AtomicLock(&locks[index]);
SDL_AtomicLock(&locks[index]);
}
static __inline__ void
leaveLock(void *a)
{
uintptr_t index = ((((uintptr_t)a) >> 3) & 0x1f);
uintptr_t index = ((((uintptr_t)a) >> 3) & 0x1f);
SDL_AtomicUnlock(&locks[index]);
SDL_AtomicUnlock(&locks[index]);
}
#ifndef SDL_AtomicSet
#undef SDL_AtomicSet
int
SDL_AtomicSet(SDL_atomic_t *a, int value)
{
@ -77,9 +83,8 @@ SDL_AtomicSet(SDL_atomic_t *a, int value)
return oldvalue;
}
#endif
#ifndef SDL_AtomicGet
#undef SDL_AtomicGet
int
SDL_AtomicGet(SDL_atomic_t *a)
{
@ -88,9 +93,8 @@ SDL_AtomicGet(SDL_atomic_t *a)
*/
return a->value;
}
#endif
#ifndef SDL_AtomicAdd
#undef SDL_AtomicAdd
int
SDL_AtomicAdd(SDL_atomic_t *a, int value)
{
@ -103,53 +107,48 @@ SDL_AtomicAdd(SDL_atomic_t *a, int value)
return oldvalue;
}
#endif
#ifndef SDL_AtomicIncRef
#undef SDL_AtomicIncRef
void
SDL_AtomicIncRef(SDL_atomic_t *a)
{
SDL_AtomicAdd(a, 1);
}
#endif
#ifndef SDL_AtomicDecRef
#undef SDL_AtomicDecRef
SDL_bool
SDL_AtomicDecRef(SDL_atomic_t *a)
{
return SDL_AtomicAdd(a, -1) == 1;
}
#endif
#ifndef SDL_AtomicCAS
int
#undef SDL_AtomicCAS
SDL_bool
SDL_AtomicCAS(SDL_atomic_t *a, int oldval, int newval)
{
int prevval;
SDL_bool retval = SDL_FALSE;
enterLock(a);
prevval = a->value;
if (prevval == oldval) {
if (a->value == oldval) {
a->value = newval;
retval = SDL_TRUE;
}
leaveLock(a);
return prevval;
return retval;
}
#endif
#ifndef SDL_AtomicSetPtr
#undef SDL_AtomicSetPtr
void
SDL_AtomicSetPtr(void** a, void* value)
{
void *prevval;
do {
prevval = *a;
} while (SDL_AtomicCASPtr(a, prevval, value) != prevval);
} while (!SDL_AtomicCASPtr(a, prevval, value));
}
#endif
#ifndef SDL_AtomicGetPtr
#undef SDL_AtomicGetPtr
void*
SDL_AtomicGetPtr(void** a)
{
@ -158,22 +157,20 @@ SDL_AtomicGetPtr(void** a)
*/
return *a;
}
#endif
#ifndef SDL_AtomicCASPtr
void* SDL_AtomicCASPtr(void **a, void *oldval, void *newval)
#undef SDL_AtomicCASPtr
SDL_bool SDL_AtomicCASPtr(void **a, void *oldval, void *newval)
{
void *prevval;
SDL_bool retval = SDL_FALSE;
enterLock(a);
prevval = *a;
if (*a == oldval) {
*a = newval;
retval = SDL_TRUE;
}
leaveLock(a);
return prevval;
return retval;
}
#endif
/* vi: set ts=4 sw=4 expandtab: */